Longitudinal associations between exclusive, dual and polytobacco use and respiratory illness among youth

Longitudinal associations between exclusive, dual and polytobacco use and respiratory illness among youth | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Longitudinal associations between exclusive, dual and polytobacco use and respiratory illness among youth Luis Zavala-Arciniega, Steven Cook, Jana Hirschtick, Yanmei Xie, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3793149/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 08 Aug, 2024 Read the published version in BMC Public Health → Version 1 posted 12 You are reading this latest preprint version Abstract Background The health consequences of polytobacco use are still well not understand. We evaluated prospective associations between exclusive, dual, and polytobacco use and diagnosed bronchitis, pneumonia, or chronic cough among US youth. Methods Data came from Waves 1–5 of the Population Assessment of Tobacco and Health Study. We categorized time-varying past 30-day tobacco use into seven categories: ( 1 ) non-current use; exclusive use of 2) cigarettes, 3) electronic nicotine delivery systems (ENDS), or 4) other combustible products (OC; pipes, hookah, and cigars); dual use of 5) ENDS + cigarettes or ENDS + OC 6) cigarettes + OC; or 7) polyuse of all three products. The outcome was incident diagnosis of bronchitis, pneumonia, or chronic cough. We conducted weighted multilevel Poisson models (person n = 17,517, 43,290 observations) to examine the longitudinal exposure-outcome relationship, adjusting for covariates: sex, age, race and ethnicity, parental education, body mass index, secondhand smoke exposure, and household use of combustible products Results Compared to nonuse, exclusive cigarette use (Incidence Rate Ratio (IRR) = 1.83, 95% CI 1.25–2.68), exclusive ENDS use (IRR = 1.53, 95% CI 1.08–2.15), combustible product + ENDS dual use (IRR = 1.90, 95% CI 1.18–3.04), cigarettes + OC dual use (IRR = 1.96, 95% CI 1.11–3.48), and polytobacco use (IRR = 3.06 95% CI 1.67–5.63) were associated with a higher incidence of bronchitis, pneumonia, or chronic cough. Conclusion We found that exclusive, dual, and poly tobacco use was associated with higher incidence of bronchitis, pneumonia, or chronic cough; Moreover, the incidence rate ratio for polytobacco use was higher than the incidence rate ratio for exclusive use compared to non-current use. polytobacco use respiratory illness epidemiology Figures Figure 1 Figure 2 Introduction Tobacco use is an important cause of morbidity among youth. 1 For example, combustible tobacco product use has been identified as a risk factor for acute respiratory diseases. 2,3 However, little is known about the respiratory health consequences of exclusive, dual (use of two products), and polyuse (three or more products) of tobacco products, which is important due to the continued introduction of new tobacco products. 4,5 Exclusive, dual, and poly tobacco use patterns are evolving for youth. A recent study using data from 2014 to 2019 found that, among youth, exclusive e-cigarette use increased (from 3.2–12.8%), while exclusive cigarette use and dual/polyuse without e-cigarettes decreased. 6 Given the rapidly changing tobacco product landscape, it is critical to understand the relationship between exclusive, dual, and polytobacco use and respiratory health outcomes among youth and young adults. Previous studies have found that cigarette use is associated with increased risk of acute respiratory health outcomes among youth and young adults. 7,8 For example, clinical and population studies have reported that current cigarette use (vs. never cigarette use) is associated with bronchitis and acute pneumonia among youth and young adults. 7,9–11 Clinical studies suggested that ENDS use is associated with lipoid pneumonia among young adults. 12–14 However, population-based studies that have evaluated the association between ENDS use and respiratory diseases among youth have produced mixed results. One longitudinal study in California among high schools students found that current, e-cigarette use (vs. nonuse) was associated with a higher risk of respiratory symptoms. 15 Results from the Population Assessment of Tobacco and Health (PATH) study reported that current e-cigarette use was not associated with wheezing episodes among youth. 16 Moreover, results from PATH studies reported that dual use combustible tobacco products was associated with a higher incidence of asthma at follow-up compared to non-use of tobacco products. 17 In contrast dual use of cigarettes and e-cigarettes cigarettes at baseline was not associated with higher asthma incidence. 17,18 While asthma association has been prospectively evaluated at national level, there is a need to evaluate the link between exclusive, dual and polytobacco use with short term respiratory outcomes such as acute bronchitis or pneumonia. One recent study of our team found that the exclusive cigarette, exclusive e-cigarette use and dual use of cigarettes and e-cigarettes was associated with bronchitis, pneumonia and chronic cough. 19 However, no studies have evaluated the link between polytobacco use the risk of bronchitis, pneumonia. We aim to fill this gap by studying this association using data from six waves of the PATH survey, a longitudinal nationally representative study, providing additional insights about the short-term health consequences of polyuse of tobacco products among youth. We hypothesize that the risk of bronchitis, pneumonia or chronic cough will be higher among those who cigarettes, e-cigarettes and other combustible products together. Methods We used restricted youth data from waves 1 to 5 of the PATH Study, including wave 4.5. The analytic sample consisted of youth between 12 to 17 years who completed at least one follow-up survey. We also included participants who aged up into the youth sample during W2 to W4.5 (shadow youth) and the replenishment sample in W4. Baseline data for each respondent referred to their first interview, which could occur between W1 to W4.5 (See Fig. 1). Data were collected using audio computer self-interviews (ACASI) in English and Spanish in the following periods: Wave 1 from September 2013 to December 2014; Wave 2 from October 2014 to October 2015; Wave 3 from October 2015 to October 2016; Wave 4 from December 2016 to January 2018; Wave 4.5 from December 2017 to November 2018; and Wave 5 from December 2018 to November 2019. A detailed description of the methodology of the PATH study has been published elsewhere. 2021 Given the use of de-identified datasets, the University of Michigan Institutional Review Board deemed this project not regulated as human subject’s research. Parent-reported bronchitis, pneumonia, or chronic cough incidence We evaluated the incidence of parent-reported bronchitis, pneumonia, or chronic cough among youth participants. Parents of the youth participants were queried, “In the past 12 months, has (Child's first name) been told by a doctor, nurse, or other health professional that (he/she) has bronchitis, pneumonia, or chronic cough?” The study outcome was measured at each wave, starting in wave 2 and could occur more than once. Exclusive, dual, and poly tobacco use as time-dependent exposure variable For exposure, we categorized time-varying past 30-day tobacco use into 7 mutually exclusive categories: ( 1 ) non-current/never tobacco use; exclusive use of ( 2 ) cigarettes, ( 3 ) electronic nicotine delivery systems (ENDS), and ( 4 ) other combustibles (OC; pipes, hookah, and cigars); dual use of ( 5 ) ENDS + combustible tobacco (cigarettes or OC), and ( 6 ) cigarettes + OC; and ( 7 ) polyuse of all three tobacco product groups. The ENDS + combustible tobacco dual use category was created as a combined ENDS + cigarettes and ENDS + OC category due to (a) small sample sizes for ENDS + cigarettes and ENDS + OC, and (b) the hypothesized similar health effect for ENDS plus any combustible product. Current tobacco product use was defined as smoked cigarettes/cigars or use e-cigarettes in the past 30 days. We lagged the exposure variable by one wave (t-1) to ensure that the tobacco variable exposure preceded the bronchitis outcome (i.e., if exposure was measured at W1, the outcome was measured at W2). Covariates We included sex (female, male), race and or ethnicity (Non-Hispanic (NH) White, NH Black, Hispanic, and Another Race/Ethnicity (including multiracial)), parental education (less than high school, high school, some college and bachelor’s degree or higher), body mass index (normal/underweight, overweight, obese), and household use of combustibles products (no, yes) as baseline covariates at the time of respondent’s first interview. Secondhand smoke exposure was measured in number of hours exposed in the past 7 days, cannabis use (yes/no), asthma (yes/no). Age was included as a categorical variable (12–14 and 15–17 years). Analysis First, we created a person-period data set containing multiple responses per participant (n = 17,517; 43,290 observations). We then calculated descriptive statistics for the sociodemographic characteristics and risk factor distributions at baseline for our analytic sample. We also calculated the time-varying prevalence of past 30-day exclusive, dual, and polyuse tobacco exposure variable by wave and the cigarette smoking intensity pattern by wave. Finally, we conducted unadjusted and adjusted weighted, multilevel Poisson models to examine the longitudinal exposure-outcome relationship across five different periods (W1-W2, W2-W3, W3-W4, W4-W4.5, and W4.5-W5). Multilevel models were used because the outcome could occur more than once, and these models adjusted for the lack of independence of the repeated observations. Adjusted models included the covariates described above. All estimates adjusted for the sample design by recalibrating the PATH weights into two-level weights to accommodate the study longitudinal hierarchy of the data set. 22 Briefly, Level-1 weights were the conditional wave-specific weights that were scaled, and their sum is equal to the number of data points available for each participant in the study. Level-2 weights were the baseline weights. In other words, Level-2 weights were the cross-sectional weights in which individuals begin in the study (i.e., Wave 1 for most participants, Waves 2-4.5 for aged-up youth, and Wave 4 for youth recruited for the replenishment sample). 22 We conducted the statistical analysis using Stata 18.1. Results Table 1 shows the baseline sociodemographic characteristics and covariate distribution for participants in our analytic sample at their baseline year (n=17,517). The baseline year corresponds to the wave that the participant entered the study. Just over half the participants were male (51.5%). More than half of respondents (53%) were NH White, 13% were NH Black, 24% were Hispanic, and 10% were from another race/ethnicity. About 40% of participants reported having a parent with a bachelor’s degree or higher. Approximately 27% of the participants reported that someone in their household used tobacco products . A total of 7.4% of the sample reported bronchitis, pneumonia, or chronic cough across the study period. Among respondents who reported the outcome (N=1,309), about 20% (n=264) reported the outcome more than once over the study period. Table 2 describes the changes in the tobacco exposure variable across waves. The prevalence of exclusive use of cigarettes and OC decreased from W1 to W5 (from 1.5% to 0.8%), while exclusive e-cigarette use increased (from 1.1% to 3.8%). Dual use of ENDS with cigarettes or OC did not change from W1 to W5, but cigarette + OC use decreased. Polyuse of tobacco products remained at about 0.3% over the study period. Table 3 shows the cigarette smoking intensity pattern by wave. Cigarette smoking intensity was not statistically different among the exclusive cigarette use, dual use, and polytobacco use categories over time. The results from the multilevel Poisson regression models can be found in Figure 2 and Supplementary table 1. There were 43,290 observations in the models corresponding to n=17,517 respondents. In the adjusted models, compared to non-current use of tobacco products, exclusive cigarette use (Incidence Rate Ratio [IRR]=1.83, 95% CI 1.25-2.68) and exclusive ENDS use (IRR=1.53, 95% CI 1.08-2.15) were associated with a higher incidence of diagnosed bronchitis, pneumonia, or chronic cough. The risk of diagnosed bronchitis, pneumonia, or chronic cough was also higher for dual use of ENDS + combustible tobacco (IRR=1.90, 95% CI 1.18-3.04), dual use of cigarettes + OC (IRR=1.96, 95% CI 1.11-3.48), and polytobacco use (IRR=3.06 95% CI 1.67-5.63), compared to non-current use of tobacco products. The only tobacco use category that was not statistically different from non-current use was exclusive OC (IRR=1.29, 95% CI 0.67-2.49). Discussion Using data from a large and nationally representative longitudinal sample, we found associations between exclusive, dual, and polyuse of tobacco products and the incidence of acute bronchitis, pneumonia, or chronic cough among youth. Exclusive cigarette use, exclusive ENDS use, dual use of ENDS with combustible tobacco, dual use of cigarettes and OC, and polyuse of cigarettes, ENDS, and OC were all associated with higher risk of acute bronchitis, pneumonia, or chronic cough, with the strongest association for polytobacco use. The current changing landscape of the tobacco market has led to increased exclusive ENDS use and decreased cigarette use and dual use with cigarettes among youth during the years of our study. However, polytobacco use remained stable during the study period. In this context of availability of multiple tobacco products, we found that adolescents using cigarettes, ENDS, or cigars exclusively or concurrently were at higher risk of developing short-term respiratory outcomes than adolescents who did not use tobacco. Moreover, our findings suggest that polyuse of tobacco products results in greater incidence of bronchitis, pneumonia, or chronic cough. Therefore, policymakers should reinforce measures that restrict access to all tobacco products, including ENDS, for adolescents to reduce their disease risk. Our finding that exclusive ENDS use and ENDS use with combustible tobacco (dual and poly) were both associated with the incidence of acute bronchitis, pneumonia, or chronic cough suggests that ENDS use among youth affects acute respiratory health. Our finding is generally consistent with findings from clinical studies, which report that e-cigarette use it is related to acute respiratory infections. 23–26 One potential explanation of the association between exclusive e-cigarette use and acute respiratory infections such as bronchitis and pneumonia is that adolescents frequently share e-cigarette devices with friends and other persons. 27 Sharing e-cigarette devices potentially could lead to an increase in respiratory infections through the exchange of saliva. Future national surveys on tobacco use should incorporate questions of sharing behaviors of e-cigarettes and other tobacco products. Consistent with our finding that exclusive cigarette use was associated with acute bronchitis, pneumonia, or chronic cough, previous studies have found that individual combustible tobacco use was associated with bronchitis and pneumonia. 9,10 By examining dual and polytobacco use, we were further able to demonstrate that the use of two or more tobacco products is associated with bronchitis, pneumonia, and chronic cough. Interestingly, the incidence rate ratio for polytobacco use compared to non-current use was higher than that for exclusive use of any individual product. This association was not explained by differences in cigarette smoking intensity patterns. Of note, cigarette smoking intensity was not statistically different among adolescents who used two or more tobacco products, compared to those who used cigarettes exclusively (Table 3 ). Therefore, our finding suggests that using two or more tobacco products may further increase the risk of adverse acute respiratory health outcomes relative to exclusive cigarette use. In contrast, we found that exclusive OC tobacco product use was not statistically associated with an increased risk of incident bronchitis, pneumonia, and chronic cough, but OC use was associated with an increased incident risk when used in combination with other tobacco products. The lack of a statistically significant association of exclusive OC use with the respiratory outcomes could be explained by the smaller sample size for the exclusive OC use category, even though the IRR was above 1. Future research is warranted to examine the independent risk of each product (i.e., hookah, cigars, and pipes) in the OC use category. This study has several limitations. First, parents were asked about bronchitis, chronic cough, and pneumonia as part of a single question in the PATH survey, so that it was not possible to separately examine these respiratory outcomes. Future longitudinal studies incorporating specific questions for each respiratory health outcome are warranted. Second, diagnosis of the respiratory outcomes were self-reported by the parents and not confirmed clinically, which might introduce information bias. Third, we cannot rule out residual confounding in our analyses. For example, PATH study assessed urbanicity of residence only at W1, so we were unable to adjust for it given the inclusion of youth shadow samples (i.e., youth who began participating in the study in W2 or after). Fourth, the outcome survey question was only assessed for youth but not adults, limiting our ability to follow participants when they aged up into the adult sample. Despite these limitations, to our knowledge, this study is important because provide new evidence of the relationship between specific tobacco products used alone or in combination and acute respiratory health effects among youth. Conclusion In the context of the rapidly changing tobacco use patterns among youth, we found that, compared to non-current use, the exclusive use of cigarettes, the exclusive use of ENDS, and the use of two or more tobacco products were strongly associated with incident bronchitis, pneumonia, and chronic cough. Policymakers should carefully consider reinforcing measures that restrict youth access to all tobacco products, including ENDS, to protect the health of the youth population in the U.S. Declarations Ethics approval and consent to participate The PATH Study was conducted by Westat and the study procedures and materials were approved by the Westat Institutional Review Board. All PATH Study respondents ages 18 and older provided informed consent, with youth respondents ages 12 to 17 providing assent while each one’s parent/legal guardian provided consent. This study used was a secondary analysis of de-identified data. Consent for publication Not applicable Availability of data and materials The dataset generated and analyzed in the current study used restricted use data from the Population Assessment of Tobacco and Health (PATH) study. Details on how to access restricted use data from the PATH Study is described in the PATH Study Restricted Use Files User Guide: https://doi.org/10.3886/ICPSR36231.v37. Researchers interested in obtaining these data from the Inter-university Consortium for Political and Social Research (ICPSR) at the University of Michigan must complete a Restricted Data Use Agreement. For additional information, please reference: https://www.icpsr.umich.edu/web/pages/NAHDAP/vde/index.html. For questions related to the study results or queries from this study please contact the correspondent author [Luis Zavala-Arciniega/ [email protected] ] Competing interests Not applicable Funding Research reported here was supported by the National Cancer Institute of the National Institutes of Health under Award Number U54- CA229974. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Author’s contributions Conceptualization, LZ-A, NF, SC, JH, DA; Methodology, YX, LZ-A.,SC.; formal analysis, LZ-A, RM; Resources, NLF, RM, DL.; Writing-review and editing, LZ-A, SC, RM, YX, NF, RM, DT, DA, GB, JH. Supervision, NF. All authors have read and agreed to publish this version of the manuscript. References U.S. Department of Health and Human Services. The Health Consequences of Smoking—50 Years of Progress: A Report of the Surgeon General. ; 2014. doi:NBK179276. Arcavi L, Benowitz NL. Cigarette smoking and infection. Arch Intern Med. 2004;164(20):2206–16. 10.1001/archinte.164.20.2206 . Aronson MD, Weiss ST, Ben RL, Komaroff AL. Association Between Cigarette Smoking and Acute Respiratory Tract Illness in Young Adults. JAMA: The Journal of the American Medical Association. 1982;248(2):181–3. 10.1001/jama.1982.03330020025023 . Barnoya J, Monzon D, Pinetta J, Grilo G, Cohen JE. New tobacco products, old advertising strategies : point- of- sale advertising in Guatemala. Published online 2021:591–3. 10.1136/tobaccocontrol-2020-055681 . Ling PM, Kim M, Egbe CO, Patanavanich R, Pinho M, Hendlin Y. Moving targets: how the rapidly changing tobacco and nicotine landscape creates advertising and promotion policy challenges. Published online 2022:222–8. 10.1136/tobaccocontrol-2021-056552 . Cook S, Ortiz Chavez S, Zavala-Arciniega L, Hirschtick JL, Fleischer NL. Trends of Single, Dual, and Polytobacco Use Among School-Based Students in the United States: An Analysis of the National Youth Tobacco Survey. Am J Health Promotion. 2023;37(8):1078–90. 10.1177/08901171231191557 . Tanski S, Halenar MJ, Edwards KC, et al. Tobacco Product Use and Functionally Important Respiratory Symptoms Among US Adolescents/Young Adults. Acad Pediatr. 2022;000. 10.1016/j.acap.2022.03.001 . Genuneit J, Weinmayr G, Radon K et al. Smoking and the incidence of asthma during adolescence: results of a large cohort study in Germany. Published online 2006:572–8. 10.1136/thx.2005.051227 . Almirall J, Bolõ I, Balanzo X, Gonza CA. Risk factors for community-acquired pneumonia in adults: a population-based case ± control study. Eur Respir J Published online 1999:349–55. Almirall J, Gonza CA. Proportion of Community-Acquired Pneumonia Cases Attributable to Tobacco Smoking *. Chest Published online 1999:375–9. 10.1378/chest.116.2.375 . Vadsala B, Murray RL, Hunter A, Lim WS, Mckeever M. Effect of tobacco smoking on the risk of developing community acquired pneumonia: A systematic review and meta-analysis. PLoS One Published online 2019:1–18. Kooragayalu S, El-zarif S, Jariwala S. Respiratory Medicine Case Reports Vaping Associated Pulmonary Injury (VAPI) with superimposed Mycoplasma pneumoniae infection. Respir Med Case Rep. 2020;29:100997. 10.1016/j.rmcr.2020.100997 . Viswam D, Trotter S, Burge PS, Walters GI. Respiratory failure caused by lipoid pneumonia from vaping e-cigarettes. BMJ Case. 2018;1:1–4. 10.1136/bcr-2018-224350 . Davidson K, Brancato A, Heetderks P, et al. Outbreak of Electronic-Cigarette–Associated Acute Lipoid Pneumonia — North Carolina, July–August 2019. Morb Mortal Wkly Rep. 2019;68(36):784–6. Tackett AP, Urman R, Barrington-Trimis J et al. Prospective study of e-cigarette use and respiratory symptoms in adolescents and young adults. 10.1136/thoraxjnl-2022-218670 . Tackett AP, Keller-Hamilton B, Smith CE, et al. Evaluation of Respiratory Symptoms Among Youth e-Cigarette Users. JAMA Netw Open. 2020;3(10):e2020671. 10.1001/jamanetworkopen.2020.20671 . Mattingly DT, Cook S, Hirschtick JL, et al. Longitudinal associations between exclusive, dual, and polytobacco use and asthma among US youth. Prev Med (Baltim). 2023;171. 10.1016/j.ypmed.2023.107512 . Patel A, Cook S, Mattingly DT, et al. Longitudinal Association Between Exclusive and Dual Use of Cigarettes and Electronic Nicotine Delivery Systems and Asthma Among U.S. Adolescents. J Adolesc Health. 2023;73(3):437–44. 10.1016/j.jadohealth.2023.04.009 . Mukerjee R, Hirschtick JL, Arciniega LZ et al. December. ENDS, cigarettes, and respiratory illness: Longitudinal associations among US youth. Am J Prev Med . Published online 2023. 10.1016/j.amepre.2023.12.005 . Hyland A, Ambrose BK, Conway KP, et al. Design and methods of the Population Assessment of Tobacco and Health (PATH) Study. Tob Control. 2017;26(4):371–8. 10.1136/tobaccocontrol-2016-052934 . Abuse USD. of H and HServicesNI of HealthNI on D, Products USD of H and HServicesF and DAdministrationC for T. Population Assessment of Tobacco and Health (PATH) Study [United States] Public-Use Files. Published online 2020. Heering S, West B, Berglund P. Analysis of Longitudinal Comples Sample Survey Data. In: CRS Press, ed. Applied Survey Data Analysis . 2nd ed.; 2017:568. Kimball A, Layer M, Tenforde MW et al. Pulmonary Illness Related to E-Cigarette Use in Illinois and Wisconsin — Final Report. New Engl J Med Published online 2020:903–16. 10.1056/NEJMoa1911614 . Mukhopadhyay S, Mehrad M, Dammert P, et al. Lung biopsy findings in severe pulmonary illness associated with E-Cigarette use (Vaping): A report of eight cases. Am J Clin Pathol. 2020;153(1):30–9. 10.1093/ajcp/aqz182 . Ansari-Gilani K, Petraszko AM, Teba CV, et al. E-cigarette use related lung disease, review of clinical and imaging findings in 3 cases. Heart Lung. 2020;49(2):139–43. 10.1016/j.hrtlng.2020.01.005 . Jonas AM, Raj R. Vaping-Related Acute Parenchymal Lung Injury: A Systematic Review. Chest. 2020;158(4):1555–65. 10.1016/j.chest.2020.03.085 . Seitz CM, Staley ME, Kearley J, et al. E-cigarette sharing behavior among college students: An exploratory study. J Am Coll Health. 2022;70(5):1297–300. 10.1080/07448481.2020.1800710 . Tables Table 1. Baseline sociodemographic characteristics and smoking behavior, Population Assessment of Tobacco & Health Study (Wave 1, 2013, 2014) among youth (n=17,517) % 95% CI n Sex Male 51.5 [50.7, 52.2] 9098 Female 48.5 [47.7, 49.3] 8416 Age* 12-14 years 60.5 [59.4,61.6] 5437 15-17 years 39.5 [38.4,40.6] 3525 Race/ethnicity NH White 53.0 [40.2,53.8] 8390 NH Black 12.9 [12.4,13.5] 2280 Hispanic 24.1 [23.4,24.7] 5160 Another Race/Ethnicity 10.0 [9.5,10.5] 1678 Parental education Less than high school 13.0 [12.5,13.5] 2686 High school 20.7 [20.1,21.4] 3853 Some college 27.0 [26.2,27.7] 4730 Bachelor's degree or higher 39.2 [38.5,40.5] 6248 Baseline risk factors Second hand smoke exposure (10 hours) 0.3 [0.3,0.3] 17,517 Ever marijuana use No 93.6 [92.2,94.0] 16289 Yes 6.4 [6.0,8.8] 1228 Ever asthma diagnosis No 81.9 [81.3,82.5] 14288 Yes 18.1 [17.5,18.7] 3229 Household use of combustible products No 73.5 [72.7,74.1] 12667 Yes 26.5 [25.9,27.3] 4850 BMI - obesity Normal/underweight 64.8 [64,0,65.4] 11064 Overweight 18.3 [17.7,18.9] 3290 Obese 17.0 [16.3,17.6] 3163 Bronchitis, Pneumonia or Chronic cough episodes** None 92.6 [92.2,93.0] 16208 One 5.9 [5.5,6.2] 1045 Two or more 1.5 [1.3,1.7] 264 *Table 1 only includes the distribution of age at W1. Age was included as time-variant in the models **Bronchitis, pneumonia and Chronic cough episodes over the study period. From W2 to W5 Table 2. Time-Dependent tobacco exposure variable by wave (n=43,290 observations) Wave 1 (n=8928) Time varying poly tobacco use variable % 95% CI n Non use 95.1 [94.6, 95.5] 8485 Exclusive cigarette use 1.5 [1.2, 1.8] 132 Exclusive e-cigarette use 1.1 [0.9, 1.3] 91 Exclusive other combustible use 0.7 [0.5, 0.9] 66 Dual use of cigarettes + ENDS/ Dual use of ENDS + OC 0.7 [0.6, 0.9] 64 Dual use of cigarettes + other combustibles 0.5 [0.4, 0.7] 48 Poly use of cigarettes+ ENDS + OC 0.4 [0.3, 0.6] 43 Wave 2 (n=8,271) Non use 95.0 [94.5, 95.5] 7855 Exclusive cigarette use 1.3 [1.1, 1.6] 113 Exclusive e-cigarette use 1.4 [1.2, 1.7] 114 Exclusive other combustible use 0.8 [0.6, 1.0] 68 Dual use of cigarettes + ENDS/ Dual use of ENDS + OC 0.7 [0.5, 0.9] 59 Dual use of cigarettes + other combustibles 0.5 [0.3, 0.6] 40 Poly use of cigarettes+ ENDS + OC 0.3 [0.2, 0.4] 22 Wave 3 (n=7,825) Non use 95.6 [95.1, 96.1] 7469 Exclusive cigarette use 0.9 [0.7, 1.2] 70 Exclusive e-cigarette use 1.9 [1.6, 2.2] 151 Exclusive other combustible use 0.4 [0.3, 0.6] 38 Dual use of cigarettes + ENDS/ Dual use of ENDS + OC 0.6 [0.5, 0.9] 54 Dual use of cigarettes + other combustibles 0.3 [0.2, 0.5] 27 Poly use of cigarettes+ ENDS + OC 0.2 [0.1, 0.3] 16 Wave 4 (n=9,614) Non use 95.6 [95.1, 96.0] 9192 Exclusive cigarette use 1.0 [0.8, 1.2] 99 Exclusive e-cigarette use 2.0 [1.7, 2.4] 178 Exclusive other combustible use 0.4 [0.3, 0.6] 41 Dual use of cigarettes + ENDS/ Dual use of ENDS + OC 0.6 [0.5, 0.8] 64 Dual use of cigarettes + other combustibles 0.2 [0.1, 0.3] 19 Poly use of cigarettes+ ENDS + OC 0.2 [0.1, 0.3] 21 Wave 4.5 (n=8,652) % 95% CI n Non use 93.8 [93.3, 94.4] 8108 Exclusive cigarette use 0.8 [0.6, 1.0] 75 Exclusive e-cigarette use 3.8 [3.4, 4.3] 328 Exclusive other combustible use 0.3 [0.2, 0.4] 26 Dual use of cigarettes + ENDS/ Dual use of ENDS + OC 0.8 [0.6, 1.0] 72 Dual use of cigarettes + other combustibles 0.2 [0.1, 0.3] 18 Poly use of cigarettes+ ENDS + OC 0.3 [0.2, 0.4] 25 Table 3. Time-Dependent smoking intensity variable (cigarettes smoked per day=CPD) by wave Wave 1 Mean cigarettes per day (CPD) 95% CI n Exclusive cigarette use 1.73 [1.15, 2.32] 132 Dual use of cigarettes + ENDS or ENDS+ OC 1.85 [0.87, 2.82] 64 Dual use of cigarettes + OC 1.62 [0.87, 2.38] 48 Polyuse of cigarettes + ENDS + OC 2.38 [1.12, 3.64] 43 Wave 2 Exclusive cigarette use 1.86 [1.04, 2.69] 111 Dual use of cigarettes + ENDS or ENDS+ OC 1.62 [0.76, 2.49] 59 Dual use of cigarettes + OC 3.71 [2.30, 5.12] 40 Polyuse of cigarettes + ENDS + OC 0.96 [0.30, 1.62] 22 Wave 3 Exclusive cigarette use 1.61 [0.86, 2.36] 70 Dual use of cigarettes + ENDS or ENDS+ OC 2.19 [0.84, 3.54] 54 Dual use of cigarettes + OC 2.49 [1.12, 3.86] 27 Polyuse of cigarettes + ENDS + OC 2.43 [0.88, 3.99] 16 Wave 4 Exclusive cigarette use 1.20 [0.68, 1.72] 99 Dual use of cigarettes + ENDS or ENDS+ OC 0.52 [0.21, 0.82] 64 Dual use of cigarettes + OC 2.68 [0.08, 5.28] 19 Polyuse of cigarettes + ENDS + OC 1.32 [0.69, 1.95] 21 Wave 4.5 Exclusive cigarette use 1.11 [0.53, 1.69] 75 Dual use of cigarettes + ENDS or ENDS+ OC 0.74 [0.20, 1.29] 72 Dual use of cigarettes + OC 3.30 [0.83, 5.76] 19 Polyuse of cigarettes + ENDS + OC 1.60 [0.24, 2.96] 25 Additional Declarations No competing interests reported. Supplementary Files SupplementaryTable1.12.21.23.docx Cite Share Download PDF Status: Published Journal Publication published 08 Aug, 2024 Read the published version in BMC Public Health → Version 1 posted Editorial decision: Revision requested 18 Apr, 2024 Reviews received at journal 16 Apr, 2024 Reviewers agreed at journal 16 Apr, 2024 Reviewers agreed at journal 01 Apr, 2024 Reviews received at journal 29 Jan, 2024 Reviewers agreed at journal 19 Jan, 2024 Reviewers agreed at journal 19 Jan, 2024 Reviewers invited by journal 19 Jan, 2024 Editor assigned by journal 19 Jan, 2024 Editor invited by journal 19 Jan, 2024 Submission checks completed at journal 19 Jan, 2024 First submitted to journal 22 Dec, 2023 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Levy","email":"","orcid":"","institution":"Georgetown University","correspondingAuthor":false,"prefix":"","firstName":"David","middleName":"T.","lastName":"Levy","suffix":""},{"id":268249729,"identity":"b1131dda-e76f-41fb-970e-971067714ef4","order_by":8,"name":"Rafael Meza","email":"","orcid":"","institution":"BC Cancer Research Institute","correspondingAuthor":false,"prefix":"","firstName":"Rafael","middleName":"","lastName":"Meza","suffix":""},{"id":268249730,"identity":"78c40eb9-89cf-4dcc-bafc-7084fbb8c2e5","order_by":9,"name":"Nancy Fleischer","email":"","orcid":"","institution":"University of Michigan School of Public Health","correspondingAuthor":false,"prefix":"","firstName":"Nancy","middleName":"","lastName":"Fleischer","suffix":""}],"badges":[],"createdAt":"2023-12-22 16:59:18","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3793149/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3793149/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12889-024-19582-8","type":"published","date":"2024-08-08T15:57:12+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":49987945,"identity":"022e8662-7531-4287-8d84-5258698960c8","added_by":"auto","created_at":"2024-01-22 17:46:08","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":351064,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend.\u003c/p\u003e","description":"","filename":"Figureanalyticsample.12.21.23.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3793149/v1/93333e9ecc2d2c9baed41144.jpg"},{"id":49987946,"identity":"1c7fd0d2-1a2c-418d-b546-497ceff686e8","added_by":"auto","created_at":"2024-01-22 17:46:08","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":182014,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend.\u003c/p\u003e","description":"","filename":"Figure2..png","url":"https://assets-eu.researchsquare.com/files/rs-3793149/v1/c7220877dfdce5e896bd8cb4.png"},{"id":62298267,"identity":"66283f05-b6a7-4f2c-bab8-0d9cae86560c","added_by":"auto","created_at":"2024-08-12 16:11:26","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1398606,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3793149/v1/66b9b82f-dc3d-46f2-8516-8ebdbc77ec93.pdf"},{"id":49987947,"identity":"278636d1-3e59-4103-8e83-85ba5cd4e86f","added_by":"auto","created_at":"2024-01-22 17:46:08","extension":"docx","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":21672,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryTable1.12.21.23.docx","url":"https://assets-eu.researchsquare.com/files/rs-3793149/v1/b6bf1e2897ecb0c81632963a.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Longitudinal associations between exclusive, dual and polytobacco use and respiratory illness among youth","fulltext":[{"header":"Introduction","content":"\u003cp\u003eTobacco use is an important cause of morbidity among youth.\u003csup\u003e1\u003c/sup\u003e For example, combustible tobacco product use has been identified as a risk factor for acute respiratory diseases.\u003csup\u003e2,3\u003c/sup\u003e However, little is known about the respiratory health consequences of exclusive, dual (use of two products), and polyuse (three or more products) of tobacco products, which is important due to the continued introduction of new tobacco products.\u003csup\u003e4,5\u003c/sup\u003e Exclusive, dual, and poly tobacco use patterns are evolving for youth. A recent study using data from 2014 to 2019 found that, among youth, exclusive e-cigarette use increased (from 3.2\u0026ndash;12.8%), while exclusive cigarette use and dual/polyuse without e-cigarettes decreased.\u003csup\u003e6\u003c/sup\u003e Given the rapidly changing tobacco product landscape, it is critical to understand the relationship between exclusive, dual, and polytobacco use and respiratory health outcomes among youth and young adults.\u003c/p\u003e \u003cp\u003ePrevious studies have found that cigarette use is associated with increased risk of acute respiratory health outcomes among youth and young adults.\u003csup\u003e7,8\u003c/sup\u003e For example, clinical and population studies have reported that current cigarette use (vs. never cigarette use) is associated with bronchitis and acute pneumonia among youth and young adults.\u003csup\u003e7,9\u0026ndash;11\u003c/sup\u003e Clinical studies suggested that ENDS use is associated with lipoid pneumonia among young adults.\u003csup\u003e12\u0026ndash;14\u003c/sup\u003e However, population-based studies that have evaluated the association between ENDS use and respiratory diseases among youth have produced mixed results. One longitudinal study in California among high schools students found that current, e-cigarette use (vs. nonuse) was associated with a higher risk of respiratory symptoms.\u003csup\u003e15\u003c/sup\u003e Results from the Population Assessment of Tobacco and Health (PATH) study reported that current e-cigarette use was not associated with wheezing episodes among youth.\u003csup\u003e16\u003c/sup\u003e Moreover, results from PATH studies reported that dual use combustible tobacco products was associated with a higher incidence of asthma at follow-up compared to non-use of tobacco products.\u003csup\u003e17\u003c/sup\u003e In contrast dual use of cigarettes and e-cigarettes cigarettes at baseline was not associated with higher asthma incidence.\u003csup\u003e17,18\u003c/sup\u003e While asthma association has been prospectively evaluated at national level, there is a need to evaluate the link between exclusive, dual and polytobacco use with short term respiratory outcomes such as acute bronchitis or pneumonia. One recent study of our team found that the exclusive cigarette, exclusive e-cigarette use and dual use of cigarettes and e-cigarettes was associated with bronchitis, pneumonia and chronic cough.\u003csup\u003e19\u003c/sup\u003e However, no studies have evaluated the link between polytobacco use the risk of bronchitis, pneumonia. We aim to fill this gap by studying this association using data from six waves of the PATH survey, a longitudinal nationally representative study, providing additional insights about the short-term health consequences of polyuse of tobacco products among youth. We hypothesize that the risk of bronchitis, pneumonia or chronic cough will be higher among those who cigarettes, e-cigarettes and other combustible products together.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eWe used restricted youth data from waves 1 to 5 of the PATH Study, including wave 4.5. The analytic sample consisted of youth between 12 to 17 years who completed at least one follow-up survey. We also included participants who aged up into the youth sample during W2 to W4.5 (shadow youth) and the replenishment sample in W4. Baseline data for each respondent referred to their first interview, which could occur between W1 to W4.5 (See Fig.\u0026nbsp;1). Data were collected using audio computer self-interviews (ACASI) in English and Spanish in the following periods: Wave 1 from September 2013 to December 2014; Wave 2 from October 2014 to October 2015; Wave 3 from October 2015 to October 2016; Wave 4 from December 2016 to January 2018; Wave 4.5 from December 2017 to November 2018; and Wave 5 from December 2018 to November 2019. A detailed description of the methodology of the PATH study has been published elsewhere.\u003csup\u003e2021\u003c/sup\u003e Given the use of de-identified datasets, the University of Michigan Institutional Review Board deemed this project not regulated as human subject\u0026rsquo;s research.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eParent-reported bronchitis, pneumonia, or chronic cough incidence\u003c/h2\u003e \u003cp\u003eWe evaluated the incidence of parent-reported bronchitis, pneumonia, or chronic cough among youth participants. Parents of the youth participants were queried, \u003cem\u003e\u0026ldquo;In the past 12 months, has (Child's first name) been told by a doctor, nurse, or other health professional that (he/she) has bronchitis, pneumonia, or chronic cough?\u0026rdquo;\u003c/em\u003e The study outcome was measured at each wave, starting in wave 2 and could occur more than once.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eExclusive, dual, and poly tobacco use as time-dependent exposure variable\u003c/h2\u003e \u003cp\u003eFor exposure, we categorized time-varying past 30-day tobacco use into 7 mutually exclusive categories: (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) non-current/never tobacco use; exclusive use of (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) cigarettes, (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) electronic nicotine delivery systems (ENDS), and (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e) other combustibles (OC; pipes, hookah, and cigars); dual use of (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e) ENDS\u0026thinsp;+\u0026thinsp;combustible tobacco (cigarettes or OC), and (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e) cigarettes\u0026thinsp;+\u0026thinsp;OC; and (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e) polyuse of all three tobacco product groups. The ENDS\u0026thinsp;+\u0026thinsp;combustible tobacco dual use category was created as a combined ENDS\u0026thinsp;+\u0026thinsp;cigarettes and ENDS\u0026thinsp;+\u0026thinsp;OC category due to (a) small sample sizes for ENDS\u0026thinsp;+\u0026thinsp;cigarettes and ENDS\u0026thinsp;+\u0026thinsp;OC, and (b) the hypothesized similar health effect for ENDS plus any combustible product. Current tobacco product use was defined as smoked cigarettes/cigars or use e-cigarettes in the past 30 days. We lagged the exposure variable by one wave (t-1) to ensure that the tobacco variable exposure preceded the bronchitis outcome (i.e., if exposure was measured at W1, the outcome was measured at W2).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eCovariates\u003c/h3\u003e\n\u003cp\u003eWe included sex (female, male), race and or ethnicity (Non-Hispanic (NH) White, NH Black, Hispanic, and Another Race/Ethnicity (including multiracial)), parental education (less than high school, high school, some college and bachelor\u0026rsquo;s degree or higher), body mass index (normal/underweight, overweight, obese), and household use of combustibles products (no, yes) as baseline covariates at the time of respondent\u0026rsquo;s first interview. Secondhand smoke exposure was measured in number of hours exposed in the past 7 days, cannabis use (yes/no), asthma (yes/no). Age was included as a categorical variable (12\u0026ndash;14 and 15\u0026ndash;17 years).\u003c/p\u003e\n\u003ch3\u003eAnalysis\u003c/h3\u003e\n\u003cp\u003eFirst, we created a person-period data set containing multiple responses per participant (n\u0026thinsp;=\u0026thinsp;17,517; 43,290 observations). We then calculated descriptive statistics for the sociodemographic characteristics and risk factor distributions at baseline for our analytic sample. We also calculated the time-varying prevalence of past 30-day exclusive, dual, and polyuse tobacco exposure variable by wave and the cigarette smoking intensity pattern by wave. Finally, we conducted unadjusted and adjusted weighted, multilevel Poisson models to examine the longitudinal exposure-outcome relationship across five different periods (W1-W2, W2-W3, W3-W4, W4-W4.5, and W4.5-W5). Multilevel models were used because the outcome could occur more than once, and these models adjusted for the lack of independence of the repeated observations. Adjusted models included the covariates described above.\u003c/p\u003e \u003cp\u003eAll estimates adjusted for the sample design by recalibrating the PATH weights into two-level weights to accommodate the study longitudinal hierarchy of the data set.\u003csup\u003e22\u003c/sup\u003e Briefly, Level-1 weights were the conditional wave-specific weights that were scaled, and their sum is equal to the number of data points available for each participant in the study. Level-2 weights were the baseline weights. In other words, Level-2 weights were the cross-sectional weights in which individuals begin in the study (i.e., Wave 1 for most participants, Waves 2-4.5 for aged-up youth, and Wave 4 for youth recruited for the replenishment sample).\u003csup\u003e22\u003c/sup\u003e We conducted the statistical analysis using Stata 18.1.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eTable 1 shows the baseline sociodemographic characteristics and covariate distribution for participants in our analytic sample at their baseline year (n=17,517). The baseline year corresponds to the wave that the participant entered the study. Just over half the participants were male (51.5%). More than half of respondents (53%) were NH White, 13% were NH Black, 24% were Hispanic, and 10% were from another race/ethnicity. About 40% of participants reported having a parent with a bachelor\u0026rsquo;s degree or higher. Approximately 27% of the participants reported that someone in their household used tobacco products\u003cs\u003e.\u003c/s\u003e A total of 7.4% of the sample reported bronchitis, pneumonia, or chronic cough across the study period. Among respondents who reported the outcome (N=1,309), about 20% (n=264) reported the outcome more than once over the study period. Table 2 describes the changes in the tobacco exposure variable across waves. The prevalence of exclusive use of cigarettes and OC decreased from W1 to W5 (from 1.5% to 0.8%), while exclusive e-cigarette use increased (from 1.1% to 3.8%). Dual use of ENDS with cigarettes or OC did not change from W1 to W5, but cigarette + OC use decreased. \u0026nbsp;Polyuse of tobacco products remained at about 0.3% over the study period. Table 3 shows the cigarette smoking intensity pattern by wave. Cigarette smoking intensity was not statistically different among the exclusive cigarette use, dual use, and polytobacco use categories over time.\u003c/p\u003e\n\u003cp\u003eThe results from the multilevel Poisson regression models can be found in Figure 2 and Supplementary table 1. There were 43,290 observations in the models corresponding to n=17,517 respondents. In the adjusted models, compared to non-current use of tobacco products, exclusive cigarette use (Incidence Rate Ratio [IRR]=1.83, 95% CI 1.25-2.68) and exclusive ENDS use (IRR=1.53, 95% CI 1.08-2.15) were associated with a higher incidence of diagnosed bronchitis, pneumonia, or chronic cough. \u0026nbsp;The risk of diagnosed bronchitis, pneumonia, or chronic cough was also higher for dual use of ENDS + combustible tobacco (IRR=1.90, 95% CI 1.18-3.04), dual use of cigarettes + OC (IRR=1.96, 95% CI 1.11-3.48), and polytobacco use (IRR=3.06 95% CI 1.67-5.63), compared to non-current use of tobacco products. The only tobacco use category that was not statistically different from non-current use was exclusive OC (IRR=1.29, 95% CI 0.67-2.49).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eUsing data from a large and nationally representative longitudinal sample, we found associations between exclusive, dual, and polyuse of tobacco products and the incidence of acute bronchitis, pneumonia, or chronic cough among youth. Exclusive cigarette use, exclusive ENDS use, dual use of ENDS with combustible tobacco, dual use of cigarettes and OC, and polyuse of cigarettes, ENDS, and OC were all associated with higher risk of acute bronchitis, pneumonia, or chronic cough, with the strongest association for polytobacco use.\u003c/p\u003e \u003cp\u003eThe current changing landscape of the tobacco market has led to increased exclusive ENDS use and decreased cigarette use and dual use with cigarettes among youth during the years of our study. However, polytobacco use remained stable during the study period. In this context of availability of multiple tobacco products, we found that adolescents using cigarettes, ENDS, or cigars exclusively or concurrently were at higher risk of developing short-term respiratory outcomes than adolescents who did not use tobacco. Moreover, our findings suggest that polyuse of tobacco products results in greater incidence of bronchitis, pneumonia, or chronic cough. Therefore, policymakers should reinforce measures that restrict access to all tobacco products, including ENDS, for adolescents to reduce their disease risk.\u003c/p\u003e \u003cp\u003eOur finding that exclusive ENDS use and ENDS use with combustible tobacco (dual and poly) were both associated with the incidence of acute bronchitis, pneumonia, or chronic cough suggests that ENDS use among youth affects acute respiratory health. Our finding is generally consistent with findings from clinical studies, which report that e-cigarette use it is related to acute respiratory infections.\u003csup\u003e23\u0026ndash;26\u003c/sup\u003e One potential explanation of the association between exclusive e-cigarette use and acute respiratory infections such as bronchitis and pneumonia is that adolescents frequently share e-cigarette devices with friends and other persons.\u003csup\u003e27\u003c/sup\u003e Sharing e-cigarette devices potentially could lead to an increase in respiratory infections through the exchange of saliva. Future national surveys on tobacco use should incorporate questions of sharing behaviors of e-cigarettes and other tobacco products.\u003c/p\u003e \u003cp\u003eConsistent with our finding that exclusive cigarette use was associated with acute bronchitis, pneumonia, or chronic cough, previous studies have found that individual combustible tobacco use was associated with bronchitis and pneumonia.\u003csup\u003e9,10\u003c/sup\u003e By examining dual and polytobacco use, we were further able to demonstrate that the use of two or more tobacco products is associated with bronchitis, pneumonia, and chronic cough. Interestingly, the incidence rate ratio for polytobacco use compared to non-current use was higher than that for exclusive use of any individual product. This association was not explained by differences in cigarette smoking intensity patterns. Of note, cigarette smoking intensity was not statistically different among adolescents who used two or more tobacco products, compared to those who used cigarettes exclusively (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Therefore, our finding suggests that using two or more tobacco products may further increase the risk of adverse acute respiratory health outcomes relative to exclusive cigarette use.\u003c/p\u003e \u003cp\u003eIn contrast, we found that exclusive OC tobacco product use was not statistically associated with an increased risk of incident bronchitis, pneumonia, and chronic cough, but OC use was associated with an increased incident risk when used in combination with other tobacco products. The lack of a statistically significant association of exclusive OC use with the respiratory outcomes could be explained by the smaller sample size for the exclusive OC use category, even though the IRR was above 1. Future research is warranted to examine the independent risk of each product (i.e., hookah, cigars, and pipes) in the OC use category.\u003c/p\u003e \u003cp\u003eThis study has several limitations. First, parents were asked about bronchitis, chronic cough, and pneumonia as part of a single question in the PATH survey, so that it was not possible to separately examine these respiratory outcomes. Future longitudinal studies incorporating specific questions for each respiratory health outcome are warranted. Second, diagnosis of the respiratory outcomes were self-reported by the parents and not confirmed clinically, which might introduce information bias. Third, we cannot rule out residual confounding in our analyses. For example, PATH study assessed urbanicity of residence only at W1, so we were unable to adjust for it given the inclusion of youth shadow samples (i.e., youth who began participating in the study in W2 or after). Fourth, the outcome survey question was only assessed for youth but not adults, limiting our ability to follow participants when they aged up into the adult sample. Despite these limitations, to our knowledge, this study is important because provide new evidence of the relationship between specific tobacco products used alone or in combination and acute respiratory health effects among youth.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn the context of the rapidly changing tobacco use patterns among youth, we found that, compared to non-current use, the exclusive use of cigarettes, the exclusive use of ENDS, and the use of two or more tobacco products were strongly associated with incident bronchitis, pneumonia, and chronic cough. Policymakers should carefully consider reinforcing measures that restrict youth access to all tobacco products, including ENDS, to protect the health of the youth population in the U.S.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe PATH Study was conducted by Westat and the study procedures and materials were approved by the Westat Institutional Review Board. All PATH Study respondents ages 18 and older provided informed consent, with youth respondents ages 12 to 17 providing assent while each one\u0026rsquo;s parent/legal guardian provided consent. This study used was a secondary analysis of de-identified data.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials \u0026nbsp; \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe dataset generated and analyzed in the current study used restricted use data from the Population Assessment of Tobacco and Health (PATH) study. Details on how to access restricted use data from the PATH Study is described in the PATH Study Restricted Use Files User Guide: https://doi.org/10.3886/ICPSR36231.v37. Researchers interested in obtaining these data from the Inter-university Consortium for Political and Social Research (ICPSR) at the University of Michigan must complete a Restricted Data Use Agreement. For additional information, please reference: https://www.icpsr.umich.edu/web/pages/NAHDAP/vde/index.html. For questions related to the study results or queries from this study please contact the correspondent author [Luis Zavala-Arciniega/[email protected]]\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eResearch reported here was supported by the National Cancer Institute of the National Institutes of Health under Award Number U54-\u0026nbsp;CA229974. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor\u0026rsquo;s contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization, LZ-A, NF, SC, JH, DA; Methodology, YX, LZ-A.,SC.; formal analysis, LZ-A, RM; Resources, NLF, RM, DL.; Writing-review and editing, LZ-A, SC, RM, YX, NF, RM, DT, DA, GB, JH. Supervision, NF. All authors have read and agreed to publish this version of the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eU.S. Department of Health and Human Services. The Health Consequences of Smoking\u0026mdash;50 Years of Progress: A Report of the Surgeon General. ; 2014. doi:NBK179276.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eArcavi L, Benowitz NL. Cigarette smoking and infection. Arch Intern Med. 2004;164(20):2206\u0026ndash;16. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1001/archinte.164.20.2206\u003c/span\u003e\u003cspan address=\"10.1001/archinte.164.20.2206\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAronson MD, Weiss ST, Ben RL, Komaroff AL. Association Between Cigarette Smoking and Acute Respiratory Tract Illness in Young Adults. JAMA: The Journal of the American Medical Association. 1982;248(2):181\u0026ndash;3. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1001/jama.1982.03330020025023\u003c/span\u003e\u003cspan address=\"10.1001/jama.1982.03330020025023\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarnoya J, Monzon D, Pinetta J, Grilo G, Cohen JE. New tobacco products, old advertising strategies : point- of- sale advertising in Guatemala. Published online 2021:591\u0026ndash;3. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1136/tobaccocontrol-2020-055681\u003c/span\u003e\u003cspan address=\"10.1136/tobaccocontrol-2020-055681\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLing PM, Kim M, Egbe CO, Patanavanich R, Pinho M, Hendlin Y. Moving targets: how the rapidly changing tobacco and nicotine landscape creates advertising and promotion policy challenges. Published online 2022:222\u0026ndash;8. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1136/tobaccocontrol-2021-056552\u003c/span\u003e\u003cspan address=\"10.1136/tobaccocontrol-2021-056552\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCook S, Ortiz Chavez S, Zavala-Arciniega L, Hirschtick JL, Fleischer NL. Trends of Single, Dual, and Polytobacco Use Among School-Based Students in the United States: An Analysis of the National Youth Tobacco Survey. Am J Health Promotion. 2023;37(8):1078\u0026ndash;90. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1177/08901171231191557\u003c/span\u003e\u003cspan address=\"10.1177/08901171231191557\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTanski S, Halenar MJ, Edwards KC, et al. Tobacco Product Use and Functionally Important Respiratory Symptoms Among US Adolescents/Young Adults. Acad Pediatr. 2022;000. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.acap.2022.03.001\u003c/span\u003e\u003cspan address=\"10.1016/j.acap.2022.03.001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGenuneit J, Weinmayr G, Radon K et al. Smoking and the incidence of asthma during adolescence: results of a large cohort study in Germany. Published online 2006:572\u0026ndash;8. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1136/thx.2005.051227\u003c/span\u003e\u003cspan address=\"10.1136/thx.2005.051227\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlmirall J, Bol\u0026otilde; I, Balanzo X, Gonza CA. Risk factors for community-acquired pneumonia in adults: a population-based case\u0026thinsp;\u0026plusmn;\u0026thinsp;control study. Eur Respir J Published online 1999:349\u0026ndash;55.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlmirall J, Gonza CA. Proportion of Community-Acquired Pneumonia Cases Attributable to Tobacco Smoking *. Chest Published online 1999:375\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1378/chest.116.2.375\u003c/span\u003e\u003cspan address=\"10.1378/chest.116.2.375\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVadsala B, Murray RL, Hunter A, Lim WS, Mckeever M. Effect of tobacco smoking on the risk of developing community acquired pneumonia: A systematic review and meta-analysis. PLoS One Published online 2019:1\u0026ndash;18.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKooragayalu S, El-zarif S, Jariwala S. Respiratory Medicine Case Reports Vaping Associated Pulmonary Injury (VAPI) with superimposed Mycoplasma pneumoniae infection. Respir Med Case Rep. 2020;29:100997. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.rmcr.2020.100997\u003c/span\u003e\u003cspan address=\"10.1016/j.rmcr.2020.100997\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eViswam D, Trotter S, Burge PS, Walters GI. Respiratory failure caused by lipoid pneumonia from vaping e-cigarettes. BMJ Case. 2018;1:1\u0026ndash;4. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1136/bcr-2018-224350\u003c/span\u003e\u003cspan address=\"10.1136/bcr-2018-224350\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDavidson K, Brancato A, Heetderks P, et al. Outbreak of Electronic-Cigarette\u0026ndash;Associated Acute Lipoid Pneumonia \u0026mdash; North Carolina, July\u0026ndash;August 2019. Morb Mortal Wkly Rep. 2019;68(36):784\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTackett AP, Urman R, Barrington-Trimis J et al. Prospective study of e-cigarette use and respiratory symptoms in adolescents and young adults. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1136/thoraxjnl-2022-218670\u003c/span\u003e\u003cspan address=\"10.1136/thoraxjnl-2022-218670\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTackett AP, Keller-Hamilton B, Smith CE, et al. Evaluation of Respiratory Symptoms Among Youth e-Cigarette Users. JAMA Netw Open. 2020;3(10):e2020671. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1001/jamanetworkopen.2020.20671\u003c/span\u003e\u003cspan address=\"10.1001/jamanetworkopen.2020.20671\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMattingly DT, Cook S, Hirschtick JL, et al. Longitudinal associations between exclusive, dual, and polytobacco use and asthma among US youth. Prev Med (Baltim). 2023;171. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.ypmed.2023.107512\u003c/span\u003e\u003cspan address=\"10.1016/j.ypmed.2023.107512\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePatel A, Cook S, Mattingly DT, et al. Longitudinal Association Between Exclusive and Dual Use of Cigarettes and Electronic Nicotine Delivery Systems and Asthma Among U.S. Adolescents. J Adolesc Health. 2023;73(3):437\u0026ndash;44. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jadohealth.2023.04.009\u003c/span\u003e\u003cspan address=\"10.1016/j.jadohealth.2023.04.009\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMukerjee R, Hirschtick JL, Arciniega LZ et al. December. ENDS, cigarettes, and respiratory illness: Longitudinal associations among US youth. \u003cem\u003eAm J Prev Med\u003c/em\u003e. Published online 2023. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.amepre.2023.12.005\u003c/span\u003e\u003cspan address=\"10.1016/j.amepre.2023.12.005\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHyland A, Ambrose BK, Conway KP, et al. Design and methods of the Population Assessment of Tobacco and Health (PATH) Study. Tob Control. 2017;26(4):371\u0026ndash;8. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1136/tobaccocontrol-2016-052934\u003c/span\u003e\u003cspan address=\"10.1136/tobaccocontrol-2016-052934\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbuse USD. of H and HServicesNI of HealthNI on D, Products USD of H and HServicesF and DAdministrationC for T. Population Assessment of Tobacco and Health (PATH) Study [United States] Public-Use Files. Published online 2020.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHeering S, West B, Berglund P. Analysis of Longitudinal Comples Sample Survey Data. In: CRS Press, ed. \u003cem\u003eApplied Survey Data Analysis\u003c/em\u003e. 2nd ed.; 2017:568.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKimball A, Layer M, Tenforde MW et al. Pulmonary Illness Related to E-Cigarette Use in Illinois and Wisconsin \u0026mdash; Final Report. New Engl J Med Published online 2020:903\u0026ndash;16. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1056/NEJMoa1911614\u003c/span\u003e\u003cspan address=\"10.1056/NEJMoa1911614\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMukhopadhyay S, Mehrad M, Dammert P, et al. Lung biopsy findings in severe pulmonary illness associated with E-Cigarette use (Vaping): A report of eight cases. Am J Clin Pathol. 2020;153(1):30\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/ajcp/aqz182\u003c/span\u003e\u003cspan address=\"10.1093/ajcp/aqz182\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAnsari-Gilani K, Petraszko AM, Teba CV, et al. E-cigarette use related lung disease, review of clinical and imaging findings in 3 cases. Heart Lung. 2020;49(2):139\u0026ndash;43. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.hrtlng.2020.01.005\u003c/span\u003e\u003cspan address=\"10.1016/j.hrtlng.2020.01.005\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJonas AM, Raj R. Vaping-Related Acute Parenchymal Lung Injury: A Systematic Review. Chest. 2020;158(4):1555\u0026ndash;65. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.chest.2020.03.085\u003c/span\u003e\u003cspan address=\"10.1016/j.chest.2020.03.085\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSeitz CM, Staley ME, Kearley J, et al. E-cigarette sharing behavior among college students: An exploratory study. J Am Coll Health. 2022;70(5):1297\u0026ndash;300. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1080/07448481.2020.1800710\u003c/span\u003e\u003cspan address=\"10.1080/07448481.2020.1800710\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 1. Baseline sociodemographic characteristics and smoking behavior, Population Assessment of Tobacco \u0026amp; Health Study (Wave 1, 2013, 2014) among youth (n=17,517)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003en\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eSex\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; Male\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e51.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[50.7, 52.2]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e9098\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; Female\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e48.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[47.7, 49.3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e8416\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e12-14 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e60.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[59.4,61.6]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e5437\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e15-17 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e39.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[38.4,40.6]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e3525\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eRace/ethnicity\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; NH White\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e53.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[40.2,53.8]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e8390\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; NH Black\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e12.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[12.4,13.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e2280\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; Hispanic\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e24.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[23.4,24.7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e5160\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; Another Race/Ethnicity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e10.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[9.5,10.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e1678\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eParental education\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; Less than high school\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e13.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[12.5,13.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e2686\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; High school\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e20.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[20.1,21.4]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e3853\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; Some college\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e27.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[26.2,27.7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e4730\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; Bachelor\u0026apos;s degree or higher\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e39.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[38.5,40.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e6248\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eBaseline risk factors\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eSecond hand smoke exposure (10 hours)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[0.3,0.3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e17,517\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eEver marijuana use\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; No\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e93.6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[92.2,94.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e16289\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; Yes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e6.4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[6.0,8.8]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e1228\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eEver asthma diagnosis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;No\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e81.9\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[81.3,82.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e14288\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;Yes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e18.1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[17.5,18.7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e3229\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eHousehold use of combustible products\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; No\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e73.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[72.7,74.1]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e12667\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; Yes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e26.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[25.9,27.3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e4850\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eBMI - obesity\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003eNormal/underweight\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e64.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[64,0,65.4]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e11064\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003eOverweight\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e18.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[17.7,18.9]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e3290\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003eObese\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e17.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[16.3,17.6]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e3163\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eBronchitis, Pneumonia or Chronic cough episodes**\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003eNone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e92.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[92.2,93.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e16208\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003eOne\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e5.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[5.5,6.2]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e1045\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"54.8780487804878%\" valign=\"top\"\u003e\n \u003cp\u003eTwo or more\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.634146341463415%\" valign=\"top\"\u003e\n \u003cp\u003e1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.51219512195122%\" valign=\"top\"\u003e\n \u003cp\u003e[1.3,1.7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.975609756097562%\" valign=\"top\"\u003e\n \u003cp\u003e264\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e*Table 1 only includes the distribution of age at W1. Age was included as time-variant in the models\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e**Bronchitis, pneumonia and Chronic cough episodes over the study period. From W2 to W5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"546\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 2. Time-Dependent tobacco exposure variable by wave (n=43,290 observations)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"43.956043956043956%\" colspan=\"3\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eWave 1 (n=8928)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eTime varying poly tobacco use variable\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003en\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Non use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e95.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[94.6, 95.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e8485\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[1.2, 1.8]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e132\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive e-cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.9, 1.3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e91\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive other combustible use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.5, 0.9]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e66\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + ENDS/ Dual use of ENDS \u0026nbsp;+ OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.6, 0.9]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e64\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + other combustibles\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.4, 0.7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e48\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003ePoly use of cigarettes+ ENDS + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.3, 0.6]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e43\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"43.956043956043956%\" colspan=\"3\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eWave 2 (n=8,271)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Non use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e95.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[94.5, 95.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e7855\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[1.1, 1.6]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e113\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive e-cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[1.2, 1.7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e114\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive other combustible use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.6, 1.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e68\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + ENDS/ Dual use of ENDS \u0026nbsp;+ OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.5, 0.9]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e59\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + other combustibles\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.3, 0.6]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003ePoly use of cigarettes+ ENDS + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.2, 0.4]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"43.956043956043956%\" colspan=\"3\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eWave 3 (n=7,825)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Non use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e95.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[95.1, 96.1]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e7469\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.7, 1.2]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e70\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive e-cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[1.6, 2.2]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e151\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive other combustible use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.3, 0.6]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e38\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + ENDS/ Dual use of ENDS \u0026nbsp;+ OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.5, 0.9]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + other combustibles\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.2, 0.5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003ePoly use of cigarettes+ ENDS + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.1, 0.3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"43.956043956043956%\" colspan=\"3\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eWave 4 (n=9,614)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Non use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e95.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[95.1, 96.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e9192\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.8, 1.2]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e99\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive e-cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[1.7, 2.4]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e178\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive other combustible use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.3, 0.6]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e41\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + ENDS/ Dual use of ENDS \u0026nbsp;+ OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.5, 0.8]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e64\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + other combustibles\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.1, 0.3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003ePoly use of cigarettes+ ENDS + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.1, 0.3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"43.956043956043956%\" colspan=\"3\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eWave 4.5 (n=8,652)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003en\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Non use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e93.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[93.3, 94.4]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e8108\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.6, 1.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e75\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive e-cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e3.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[3.4, 4.3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e328\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive other combustible use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.2, 0.4]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + ENDS/ Dual use of ENDS \u0026nbsp;+ OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.6, 1.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e72\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + other combustibles\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.1, 0.3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"56.043956043956044%\" valign=\"bottom\"\u003e\n \u003cp\u003ePoly use of cigarettes+ ENDS + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.087912087912088%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.2, 0.4]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.582417582417584%\" valign=\"bottom\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"432\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 3. Time-Dependent smoking intensity variable (cigarettes smoked per day=CPD) by wave\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"47.22222222222222%\" colspan=\"3\" valign=\"bottom\"\u003e\n \u003cp\u003eWave 1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003eMean cigarettes per day (CPD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003en\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[1.15, 2.32]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e132\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of \u0026nbsp;cigarettes + ENDS or ENDS+ OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.85\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.87, 2.82]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e64\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.87, 2.38]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e48\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003ePolyuse of cigarettes + ENDS + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e2.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[1.12, 3.64]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e43\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"47.22222222222222%\" colspan=\"3\" valign=\"bottom\"\u003e\n \u003cp\u003eWave 2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[1.04, 2.69]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e111\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of \u0026nbsp;cigarettes + ENDS or ENDS+ OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.76, 2.49]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e59\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e3.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[2.30, 5.12]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003ePolyuse of cigarettes + ENDS + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.30, 1.62]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"47.22222222222222%\" colspan=\"3\" valign=\"bottom\"\u003e\n \u003cp\u003eWave 3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.86, 2.36]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e70\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of \u0026nbsp;cigarettes + ENDS or ENDS+ OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e2.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.84, 3.54]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e2.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[1.12, 3.86]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003ePolyuse of cigarettes + ENDS + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e2.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.88, 3.99]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"47.22222222222222%\" colspan=\"3\" valign=\"bottom\"\u003e\n \u003cp\u003eWave 4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.68, 1.72]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e99\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of \u0026nbsp;cigarettes + ENDS or ENDS+ OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.21, 0.82]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e64\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e2.68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.08, 5.28]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003ePolyuse of cigarettes + ENDS + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.69, 1.95]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd width=\"47.22222222222222%\" colspan=\"3\" valign=\"bottom\"\u003e\n \u003cp\u003eWave 4.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eExclusive cigarette use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.53, 1.69]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e75\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of \u0026nbsp;cigarettes + ENDS or ENDS+ OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.20, 1.29]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e72\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003eDual use of cigarettes + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e3.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.83, 5.76]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"52.77777777777778%\" valign=\"bottom\"\u003e\n \u003cp\u003ePolyuse of cigarettes + ENDS + OC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.055555555555557%\" valign=\"bottom\"\u003e\n \u003cp\u003e1.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.666666666666668%\" valign=\"bottom\"\u003e\n \u003cp\u003e[0.24, 2.96]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.5%\" valign=\"bottom\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-public-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pubh","sideBox":"Learn more about [BMC Public Health](http://bmcpublichealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pubh/default.aspx","title":"BMC Public Health","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"polytobacco use, respiratory illness, epidemiology","lastPublishedDoi":"10.21203/rs.3.rs-3793149/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3793149/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eThe health consequences of polytobacco use are still well not understand. We evaluated prospective associations between exclusive, dual, and polytobacco use and diagnosed bronchitis, pneumonia, or chronic cough among US youth.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eData came from Waves 1\u0026ndash;5 of the Population Assessment of Tobacco and Health Study. We categorized time-varying past 30-day tobacco use into seven categories: (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) non-current use; exclusive use of 2) cigarettes, 3) electronic nicotine delivery systems (ENDS), or 4) other combustible products (OC; pipes, hookah, and cigars); dual use of 5) ENDS\u0026thinsp;+\u0026thinsp;cigarettes or ENDS\u0026thinsp;+\u0026thinsp;OC 6) cigarettes\u0026thinsp;+\u0026thinsp;OC; or 7) polyuse of all three products. The outcome was incident diagnosis of bronchitis, pneumonia, or chronic cough. We conducted weighted multilevel Poisson models (person n\u0026thinsp;=\u0026thinsp;17,517, 43,290 observations) to examine the longitudinal exposure-outcome relationship, adjusting for covariates: sex, age, race and ethnicity, parental education, body mass index, secondhand smoke exposure, and household use of combustible products\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eCompared to nonuse, exclusive cigarette use (Incidence Rate Ratio (IRR)\u0026thinsp;=\u0026thinsp;1.83, 95% CI 1.25\u0026ndash;2.68), exclusive ENDS use (IRR\u0026thinsp;=\u0026thinsp;1.53, 95% CI 1.08\u0026ndash;2.15), combustible product\u0026thinsp;+\u0026thinsp;ENDS dual use (IRR\u0026thinsp;=\u0026thinsp;1.90, 95% CI 1.18\u0026ndash;3.04), cigarettes\u0026thinsp;+\u0026thinsp;OC dual use (IRR\u0026thinsp;=\u0026thinsp;1.96, 95% CI 1.11\u0026ndash;3.48), and polytobacco use (IRR\u0026thinsp;=\u0026thinsp;3.06 95% CI 1.67\u0026ndash;5.63) were associated with a higher incidence of bronchitis, pneumonia, or chronic cough.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eWe found that exclusive, dual, and poly tobacco use was associated with higher incidence of bronchitis, pneumonia, or chronic cough; Moreover, the incidence rate ratio for polytobacco use was higher than the incidence rate ratio for exclusive use compared to non-current use.\u003c/p\u003e","manuscriptTitle":"Longitudinal associations between exclusive, dual and polytobacco use and respiratory illness among youth","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-01-22 17:46:03","doi":"10.21203/rs.3.rs-3793149/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-04-18T05:19:37+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-04-16T22:59:51+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"a70a8749-ed0d-4e94-ab6e-ea2ec2c6624e","date":"2024-04-16T15:28:59+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"360a5ce1-f596-4864-bc4c-a90a85dded05","date":"2024-04-01T11:41:17+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-01-29T19:11:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"502fe030-d272-47e9-a29c-9ca36b481ea2","date":"2024-01-19T11:52:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"e0e09b0c-6fd9-4150-a71b-4a48ee2fbdec","date":"2024-01-19T10:17:43+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-01-19T09:37:56+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-01-19T09:33:44+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-01-19T07:49:13+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-01-19T07:43:28+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Public Health","date":"2023-12-22T16:54:45+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-public-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pubh","sideBox":"Learn more about [BMC Public Health](http://bmcpublichealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/pubh/default.aspx","title":"BMC Public Health","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"bf107e79-51dd-491b-8b4a-30cf257ca2fc","owner":[],"postedDate":"January 22nd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-08-12T16:00:36+00:00","versionOfRecord":{"articleIdentity":"rs-3793149","link":"https://doi.org/10.1186/s12889-024-19582-8","journal":{"identity":"bmc-public-health","isVorOnly":false,"title":"BMC Public Health"},"publishedOn":"2024-08-08 15:57:12","publishedOnDateReadable":"August 8th, 2024"},"versionCreatedAt":"2024-01-22 17:46:03","video":"","vorDoi":"10.1186/s12889-024-19582-8","vorDoiUrl":"https://doi.org/10.1186/s12889-024-19582-8","workflowStages":[]},"version":"v1","identity":"rs-3793149","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3793149","identity":"rs-3793149","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}