A study of the effect of smoking on vocal cord structure and function evaluated by narrow band imaging and stroboscopy

A study of the effect of smoking on vocal cord structure and function evaluated by narrow band imaging and stroboscopy | 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 A study of the effect of smoking on vocal cord structure and function evaluated by narrow band imaging and stroboscopy Krutika Yadav, Prasun Mishra, Chethana R This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7379371/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract Background : Inhaling tobacco smoke leads to inflammation of airways. Previous studies have focused on effect of smoking through cadaveric study of vocal cords and study of acoustic parameters. However, literature search did not reveal any study on evaluating effect of smoking on structure and function of vocal cords both. This study was designed with purpose to evaluate effects of smoking on the vocal cord structure and function in adult patients. This study involves 100 participants who came to ENT OPD with complaints related to throat and history of smoking for more than 5 years with at least 5 cigarettes/day. These participants were evaluated for vocal cord function and structure by Stroboscopic evaluation and Narrow band imaging(NBI) with Fibre-optic laryngoscopy . Results : This study included 100 subjects with mean age of 46.65 ±11.58 years and showed male predominance. Fundamental Frequency(Fo) of vocal cords in males was between range of 110-110 Hz in 47 subjects(73.4% of males) and between 111- 120 in 17 cases(26.6% of males). In females, Fundamental Frequency was in range of 200-210 in 31 subjects(86.1% of females) and in 5 subjects(13.9% of females) in range of 220-220 Hz. Among functional findings seen on stroboscopy, 10 subjects had incomplete glottic closure, 14 subjects had asymmetrical and 8 subjects had aperiodic vocal cord vibrations. In terms of mucosal waves, reduced(20.0%), increased(2.0%), and absent(1.0%) mucosal waves were seen in subjects with abnormal mucosal waves with rest of subjects having normal findings. While reduced(21.0%) and increased(2.0%) amplitude was seen in subjects with abnormal amplitudes and rest of subjects having normal findings. Narrow band imaging findings showed a predominance of Type II(63.0%), followed by Type I(22.0%), Type III(13.0%), and Type Vc(2.0%). In this study, various structural pathologies were seen in subjects including bilateral keratosis(5.0%), increased vascularity(3.0%), unilateral keratosis(3.0%), ulcerative growth(3.0%), edematous cord(3%), and few other findings in few subjects. Conclusions : Smoking has effect on function of vocal cords depicted by lower fundamental frequency. Other functional parameters were abnormal only in few subjects. Organic voice disorders were found in only few smokers. Smoking stroboscopy narrow band imaging vocal cords larynx Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Background Cigarette smoking causes negative effects on various systems of our body. Inhaling tobacco smoke leads to inflammation of the airways, resulting in increased mucus production and irritation.[ 1 ] Smoking also has a harmful effect on the environment as it degrades ecosystem and increases air pollution. Many people follow this negative habit, not understanding the intensity of damage to not only their health, financial standing, and health of their immediate family members.[ 1 ] A literature review indicates that smoking has detrimental impacts on the structure of the vocal cords, as demonstrated in a study by Kelleher et al which examined the histology of cadaveric vocal cord specimens, revealing that collagen fibers were more dispersed in mid-membranous part in smokers as compared to non-smokers.[ 2 ] A study conducted in 2004, shows the effect of smoking on acoustic parameters which showed that vocal Tremor Parameters (FTRI, ATRI) had significantly increased and Frequency Perturbation Parameters (jitter, vFo, SPPQ) were higher in smokers.[ 3 ] Though studies showing the effect of smoking through cadaveric study of vocal cords or through acoustic parameters have been done, literature search did not reveal any study on evaluating effect of smoking on structure and function of vocal cords both. This study was designed with the purpose to evaluate the effects of smoking on the vocal cord structure and function in adult patients with stroboscopy and narrow band imaging (NBI) in a tertiary care centre and it will help in early detection of development of structural changes in vocal cords. This will aid to prevent complications and development of malignancies and if possible to generate awareness among the population regarding the harmful effects of smoking on vocal health and encourage people in eliminating this habit. Methods This is a descriptive cross-sectional study conducted in ENT OPD and Voice clinic in a tertiary care centre. It involves 100 participants who came to ENT OPD with complaints related to throat and history of smoking for more than 5 years with at least 5 cigarettes/day.[ 4 ] Exclusion criteria of the study being participants with upper respiratory tract infections, allergic rhinitis, asthma, reflux laryngitis and lesions of the nasopharynx and oropharynx. Participants not willing to be a part of this study were excluded from the study. Written informed consent was taken from each participant. A detailed history regarding smoking of the participants was taken including number of cigarettes smoked in a day, form of tobacco in which it was smoked and smoking duration. Thorough ENT examination of participants was done. Participants were evaluated for vocal cord function and structure by Stroboscopic evaluation and Narrow band imaging with Fibre-optic laryngoscopy. Statistical Analysis The distribution of variables across the two study groups was compared using various statistical tests, including the Chi-Square test or Fisher's exact probability test for categorical variables, independent sample t-test for normally distributed continuous variables. A p-value of less than 0.05 was considered statistically significant throughout the study. The entire dataset was analyzed using Statistical Package for Social Sciences (SPSS version 22.0, IBM Corporation, NY; USA) for MS Windows. Results In this study out of 100 subjects, majority of subjects (46.0%) were between 31-40 years old. The mean age was 46.65 ±11.58 years. The study population showed a predominance of males, accounting for 64 subjects (64.0%), while females comprised 36 subjects (36.0%), indicating a male preponderance with a male-to-female ratio of approximately 1.78:1. Fundamental Frequency of vocal cords in males found on stroboscopy was between the range of 110-110 Hz in 47 subjects (73.4% of males) and between 111- 120 in 17 cases (26.6% of males). In females, Fundamental Frequency was in the range of 200-210 in 31 subjects (86.1% of females) and 5 subjects (13.9% of females) had fundamental frequency in the range of 220-220 Hz as shown in Table 1. Tables Table 1: Distribution of Fundamental frequency of subjects studied. Fundamental frequency Range (Hz) No. of subjects % of subjects Male (n=64) 100 – 110 47 73.4 111 – 120 17 26.6 Female (n=36) 200 – 210 31 86.1 211 – 220 5 13.9 The majority of cases (90.0%) had complete glottic closure, indicating normal vocal cord function, while a smaller proportion (10.0%) had incomplete closure, suggesting potential vocal cord dysfunction as shown in Table 2. On stroboscopy, most cases (86.0%) had symmetrical vocal cord vibration, indicating normal anatomy, whereas a minority (14.0%) had asymmetrical vocal cord vibration, which could be indicative of underlying pathology as shown in Table 2. Periodic vocal cord vibration was observed in the majority of cases (92.0%), suggesting normal vocal cord function, while a small proportion (8.0%) had aperiodic vibration, indicating potential vocal cord dysfunction as shown in Table 2. The mucosal waves were normal in most cases (77.0%), while alterations in the wave pattern were observed in some cases, including reduced (20.0%), increased (2.0%), and absent (1.0%) mucosal waves as shown in Table 2. The amplitude of vocal cord vibration was normal in most cases (77.0%), while some cases had reduced (21.0%) or increased (2.0%) amplitude, indicating potential variations in vocal cord function as shown in Table 2. The Narrow band imaging findings showed a predominance of Type II (63.0%), followed by Type I (22.0%), Type III (13.0%), and Type Vc (2.0%). Type Vc [Figure 1]is suggestive of malignancy as shown in Table 2. Table 2: Distribution of structural changes of vocal cords in subjects of smoking No. of cases % of cases Glottic closure pattern Complete 90 90.0 Incomplete 10 10.0 Symmetry Asymmetrical 14 14.0 Symmetrical 86 86.0 Periodicity Aperiodic 8 8.0 Periodic 92 92.0 Mucosal wave Normal 77 77.0 Reduced 20 20.0 Increased 2 2.0 Absent 1 1.0 Amplitude Normal 77 77.0 Reduced 21 21.0 Increased 2 2.0 Narrow band imaging type Type I 22 22.0 Type II 63 63.0 Type III 13 13.0 Vc 2 2.0 In this study, various structural pathologies were seen in the subjects including bilateral keratosis (5.0%) [Figure 2], increased vascularity (3.0%), unilateral keratosis (3.0%), ulcerative growth (3.0%) [Figure 3], edematous cord (3%), and other findings such as vocal cord nodules[Figure 4], sulcus vocalis [Figure 5], leukoplakia, and Reinke's edema, each occurring in a smaller proportion of subjects. While 76.0% of subjects had normal vocal cords without any pathology. Among males, the distribution of structural findings of vocal cords was compared across two fundamental frequency ranges (100-110 and 111-120), and the results showed no statistically significant association between lower fundamental frequency and vocal cord findings (p-value = 0.410). The majority of cases in both frequency groups had normal vocal cords, with 72.3% in the 100-110 group and 82.4% in the 111-120 group. Among females, the distribution of structural findings of vocal cords was compared across two fundamental frequency ranges (200-210 and 211-220), and the results showed no statistically significant association between lower fundamental frequency and vocal cord findings (p-value = 0.291). The majority of female cases had normal vocal cords, with 77.4% in the 200-210 frequency group and 80.0% in the 211-220 group. Discussion Cigarette smoking causes negative effects on various systems of our body. Inhaling tobacco smoke leads to inflammation of the airways, resulting in increased mucus production and irritation.[ 1 ] Previously studies showing the effect of smoking through cadaveric study of vocal cords or through acoustic parameters have been done, but literature search did not reveal any study on evaluating effect of smoking on structure and function of vocal cords both. This study was designed with the purpose to evaluate the effects of smoking on the vocal cord structure and function in adult patients in a tertiary care centre. In this study, Fundamental Frequency of vocal cords in males found on stroboscopy was between the range of 110–110 Hz in 47 subjects (73.4% of males) and between 111–120 in 17 cases (26.6% of males). In females, Fundamental Frequency was in the range of 200–210 in 31 subjects (86.1% of females) and 5 subjects (13.9% of females) had fundamental frequency in the range of 220–220 Hz. More subjects had fundamental frequencies on the lower range. In the study conducted by Ayoub M et al , it shows that mean fundamental frequency was low in cigarette smokers ( M = 104.47, SD = 14.03) than nonsmokers ( M = 119.43, SD = 17.19) (HSD: P < 0.001).[ 5 ] The study by Gonzalez et al , states that smokers had mean fundamental frequency (Fo) lower than non-smokers. P value in men was < 0.10 and in women was < 0.01.[ 6 ] Tuhanioglu et al in his study stated that there was no significant difference between the fundamental frequency in conventional cigarettes, e- cigarettes and control group.[ 7 ] In the Meta-analysis by Byeon et al , there was a significant difference in the ‘intermediate’ level of effect size of fundamental frequency (p < 0.001).[ 8 ] In terms of functional changes in the vocal cords, fundamental frequency was seen to be lower in smokers in this study. Other functional changes were seen in few subjects involving 10% subjects had incomplete glottic closure, 14% subjects showed asymmetrical vocal cord vibration and 8% subjects had aperiodic vocal cord vibrations, 33% subjects showed abnormal mucosal waves and abnormal amplitude. Byeon H et al in his study stated that there was no association between functional voice disorders and smokers.[ 9 ] The study by Gonzalez et al , involved a combination of voice parameters of jitter, shimmer and noise to harmonic ratio, to evaluate the effect of smoking on vocal cords. These parameters showed possible neurological effects on voice by smoking.[ 6 ] Tuhanioglu et al , in his study evaluated subjective and objective voice analysis to detect functional changes in vocal cords. His study shows jitter, F0 and shimmer percentage values shows no significant difference between the smokers and non-smokers. However, significant difference was seen in shimmer dB and HNR depicting functional voice changes. [ 7 ] In the meta-analysis by Byeon et al , it is stated that smoking had moderate and significant effects on the VHI, F0 of voice, MPT, and physical functions of vocal cords.[ 8 ] In this study, various structural pathologies were seen in the subjects including bilateral keratosis (5.0%), increased vascularity (3.0%), unilateral keratosis (3.0%), ulcerative growth (3.0%), edematous cord (3%), and other findings such as vocal cord nodules, sulcus vocalis, leukoplakia, and Reinke's edema occurred in a smaller proportion. 24% of subjects had abnormal vocal cords with organic voice disorders, while 76.0% of subjects had normal vocal cords without any pathology. In the study by Byeon H et al , correlation of organic voice disorders with past smokers was 3-times higher than nonsmokers (P < 0.05), and was 3.2-times higher in current smokers as compared to non-smokers (P < 0.05).[ 9 ] Study by Kelleher et al , is a postmortem study of microstructure of vocal cords which shows smoker subjects had less fibers in mid-membranous region than at the anterior/posterior regions but non-smokers had normalized fiber density depicting influence of smoking on direction and degree of microstructure heterogeneity in vocal fold ligament.[ 10 ] Hirabayashi et al conducted a postmortem study on vocal cords to detect structural changes in smokers and drinkers which depicted significant difference in the thickness of the epithelium of vocal cords and supraglottic region in smoking and drinking patients, as compared to non-smokers and non-drinkers.[ 11 ] Among both males and females, the distribution of structural findings of vocal cords was compared across two fundamental frequency ranges, and the results showed no statistically significant association between lower fundamental frequency and vocal cord findings. This correlation was done as lower fundamental frequency in smokers was found in various previous articles[ 6 ][ 8 ][ 5 ] and considering it as a constant in smokers, organic voice disorders in smokers were studied but no correlation was found between them. The Narrow band imaging findings showed a predominance of Type II (63.0%), followed by Type I (22.0%), Type III (13.0%), and Type Vc (2.0%). Type Vc is suggestive of malignancy. This suggests that organic voice disorders were seen in very few subjects of smoking. In the study by Shibuya et al , Narrow band imaging was used to detect angiogenic squamous dysplasia in lungs in smokers.[ 12 ] Though previous studies showing the effect of smoking through cadaveric study of vocal cords or through acoustic parameters have been done, no study was conducted on evaluating effect of smoking on structure and function of vocal cords both. Use of stroboscopy to evaluate the functional changes in vocal cords was done for the first time, in previous studies functional changes were evaluated by acoustic parameters. Stroboscopy helps in detecting the vibratory characteristics of vocal cords depicting function and also detects organic lesions by mucosal wave characteristics.[ 13 ] Narrow band imaging detects neo-vascularisation which is feature of squamous cell carcinoma by using optical filter filtering white light into wavelengths of blue and green. It helps in detecting premalignant and malignant lesions.[ 14 ] Narrow band imaging to detect lesions in larynx in smokers was not studied previously. In this pilot study, stroboscopy and NBI is used to study structural and functional changes in vocal cords due to smoking. This study helps in early detection of development of changes in vocal cords. It aids to prevent complications and development of malignancies and if possible generate awareness among the population regarding the harmful effects of smoking on vocal health and encourage people in eliminating this habit. Few limitations of the study are that, sample size is small, confounding factors such as laryngopharyngeal reflux disease, stress and consumption of spicy food were not taken into consideration in this study and one time testing was done without further follow up. It was an cross-sectional study, hence comment on a direct cause and effect between smoking and voice disorders cannot be done. In future studies, combined study involving acoustic voice analysis along with stroboscopy and NBI can be done. Enrolling large number of subjects with bigger sample size, study comparing smokers and non-smokers by using a control group can be considered. Randomised control trials involving interventions such as Point-of-care ultrasound (POCUS) can be used for future studies. Conclusion In this study, our results show that smoking has an effect on the function of vocal cords by lower fundamental frequency in majority of the subjects. But other functional parameters were abnormal only in few subjects. Causality of organic voice disorders and smoking was not established. Declarations Ethics approval and consent to participate- Taken. Ethical Approval Reference Number: BVDUMC/IEC/15/25-26 Consent for publication- Taken Availability of data and material- Available Competing interests- No competing interests Funding- No Funding required Acknowledgements- The authors thank all the participants in the research. Author Contribution Dr. Krutika Yadav: study design, definition of intellectual content, literature search, data acquisition, statistical analysis, manuscript preparation, guarantorDr. Prasun Mishra: Editing data, Proof reading and revision of data. Concept, manuscript editingDr. Chethana R: data analysis, manuscript review References Gupta S, Kumar V, Gupta P. A comprehensive study on the harmful effects of the smoking on human beings. In: Challenges in Information, Communication and Computing Technology [Internet]. London: CRC Press; 2024. p. 577–82. Available from: https://www.taylorfrancis.com/books/9781003559085/chapters/10.1201/9781003559085-99 Kelleher JE, Siegmund T, Chan RW. Collagen microstructure in the vocal ligament: Initial results on the potential effects of smoking. Laryngoscope. 2014;124(9). Gonzalezabcdeg J, Carpibcdef A. Early effects of smoking on the voice: A multidimensional study [Internet]. Available from: http://www.MedSciMonit.com/pub/vol_10/no_12/4738.pdf Chethana R, Mishra P, Kaushik M, Jadhav R, Dehadaray A. Effect of Smoking on Nasal Mucociliary Clearance. Indian Journal of Otolaryngology and Head and Neck Surgery. 2022 Oct 1;74:956–9. Ayoub MR, Larrouy-Maestri P, Morsomme D. The Effect of Smoking on the Fundamental Frequency of the Speaking Voice. Journal of Voice. 2019 Sep 1;33(5):802.e11-802.e16. Gonzalezabcdeg J, Carpibcdef A. Early effects of smoking on the voice: A multidimensional study [Internet]. Available from: http://www.MedSciMonit.com/pub/vol_10/no_12/4738.pdf Tuhanioğlu B, Erkan SO, Özdaş T, Derici Ç, Tüzün K, Şenkal ÖA. The Effect of Electronic Cigarettes on Voice Quality. Journal of Voice. 2019 Sep 1;33(5):811.e13-811.e17. Byeon H, Cha S. Evaluating the effects of smoking on the voice and subjective voice problems using a meta-analysis approach. Sci Rep. 2020 Dec 1;10(1). Byeon H. Relationships among smoking, organic, and functional voice disorders in korean general population. Journal of Voice. 2015 May 1;29(3):312–6. Kelleher JE, Siegmund T, Chan RW. Collagen microstructure in the vocal ligament: Initial results on the potential effects of smoking. Laryngoscope. 2014;124(9). Hirabayashi H, Koshii K, Uno K, Ohgaki H, Nakasone Y, Fujisawa T, et al. Laryngeal Epithelial Changes on Effects of Smoking and Drinking. Auris Nasus Larynx. 1990;17(2):105–14. Shibuya K, Hoshino H, Chiyo M, Iyoda A, Yoshida S, Sekine Y, et al. High magnification bronchovideoscopy combined with narrow band imaging could detect capillary loops of angiogenic squamous dysplasia in heavy smokers at high risk for lung cancer [Internet]. Available from: www.thoraxjnl.com Mehta DD, Hillman RE. Current role of stroboscopy in laryngeal imaging. Curr Opin Otolaryngol Head Neck Surg. 2012 Dec;6(20):429–36. Sargunaraj JJE, Mathews SS, Paul RR, Michael RC, Thomas M, Gowri M, et al. Role of Narrow Band Imaging in Laryngeal Lesions: A Prospective Study from Southern India. Indian Journal of Otolaryngology and Head and Neck Surgery. 2022 Dec 1;74:5127–33. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 19 Sep, 2025 Reviews received at journal 17 Sep, 2025 Reviews received at journal 13 Sep, 2025 Reviewers agreed at journal 07 Sep, 2025 Reviewers agreed at journal 07 Sep, 2025 Reviewers invited by journal 05 Sep, 2025 Submission checks completed at journal 01 Sep, 2025 First submitted to journal 30 Aug, 2025 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7379371","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":514521342,"identity":"edcd9ea8-5cc8-4ccf-9fee-d25b25ab7d0e","order_by":0,"name":"Krutika 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on vocal cords showing type Vc pattern.\u003c/p\u003e","description":"","filename":"NBIVc.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7379371/v1/69edf02fa26f53460526d9fb.jpg"},{"id":91328002,"identity":"fb8d9821-0d39-4afd-9ad6-e379ec75e183","added_by":"auto","created_at":"2025-09-15 10:23:08","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":150579,"visible":true,"origin":"","legend":"\u003cp\u003eThick Keratosis on Bilateral Vocal cords\u003c/p\u003e","description":"","filename":"BilateralKeratosis.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7379371/v1/01498e81e598d18323edb5c5.jpg"},{"id":91329066,"identity":"6a044ba1-30a8-4ea7-b77e-16833c7f5b3e","added_by":"auto","created_at":"2025-09-15 10:31:08","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":111737,"visible":true,"origin":"","legend":"\u003cp\u003eUlcerative growth seen on Bilateral Vocal Cords\u003c/p\u003e","description":"","filename":"UlcerativeGrowth.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7379371/v1/1d1925c89c44e6c40b07a605.jpg"},{"id":91327999,"identity":"36bc314e-7a11-4876-a3e4-da41854476de","added_by":"auto","created_at":"2025-09-15 10:23:08","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":59813,"visible":true,"origin":"","legend":"\u003cp\u003eBilateral Vocal Cord Nodule\u003c/p\u003e","description":"","filename":"BilateralVocalNodule.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7379371/v1/0768a2e605924b820ef691f9.jpg"},{"id":91328009,"identity":"c57114b1-ba8d-4e19-9718-df7dc3fa1300","added_by":"auto","created_at":"2025-09-15 10:23:08","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":76841,"visible":true,"origin":"","legend":"\u003cp\u003eBilateral Sulcuc Vocalis\u003c/p\u003e","description":"","filename":"SulcusVocalis.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7379371/v1/5a8801566c095f36a85bd9b9.jpg"},{"id":91331160,"identity":"848f3fc7-7931-45eb-9128-b39f082a18b2","added_by":"auto","created_at":"2025-09-15 10:55:13","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1129455,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7379371/v1/bf7d5efa-5a4a-4e47-8169-1fc3e018fd2f.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eA study of the effect of smoking on vocal cord structure and function evaluated by narrow band imaging and stroboscopy\u003c/p\u003e","fulltext":[{"header":"Background","content":"\u003cp\u003eCigarette smoking causes negative effects on various systems of our body. Inhaling tobacco smoke leads to inflammation of the airways, resulting in increased mucus production and irritation.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eSmoking also has a harmful effect on the environment as it degrades ecosystem and increases air pollution. Many people follow this negative habit, not understanding the intensity of damage to not only their health, financial standing, and health of their immediate family members.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/p\u003e\u003cp\u003e A literature review indicates that smoking has detrimental impacts on the structure of the vocal cords, as demonstrated in a study by Kelleher et al which examined the histology of cadaveric vocal cord specimens, revealing that collagen fibers were more dispersed in mid-membranous part in smokers as compared to non-smokers.[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eA study conducted in 2004, shows the effect of smoking on acoustic parameters which showed that vocal Tremor Parameters (FTRI, ATRI) had significantly increased and Frequency Perturbation Parameters (jitter, vFo, SPPQ) were higher in smokers.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eThough studies showing the effect of smoking through cadaveric study of vocal cords or through acoustic parameters have been done, literature search did not reveal any study on evaluating effect of smoking on structure and function of vocal cords both.\u003c/p\u003e\u003cp\u003eThis study was designed with the purpose to evaluate the effects of smoking on the vocal cord structure and function in adult patients with stroboscopy and narrow band imaging (NBI) in a tertiary care centre and it will help in early detection of development of structural changes in vocal cords. This will aid to prevent complications and development of malignancies and if possible to generate awareness among the population regarding the harmful effects of smoking on vocal health and encourage people in eliminating this habit.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eThis is a descriptive cross-sectional study conducted in ENT OPD and Voice clinic in a tertiary care centre. It involves 100 participants who came to ENT OPD with complaints related to throat and history of smoking for more than 5 years with at least 5 cigarettes/day.[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] Exclusion criteria of the study being participants with upper respiratory tract infections, allergic rhinitis, asthma, reflux laryngitis and lesions of the nasopharynx and oropharynx. Participants not willing to be a part of this study were excluded from the study.\u003c/p\u003e\u003cp\u003e Written informed consent was taken from each participant. A detailed history regarding smoking of the participants was taken including number of cigarettes smoked in a day, form of tobacco in which it was smoked and smoking duration. Thorough ENT examination of participants was done. Participants were evaluated for vocal cord function and structure by Stroboscopic evaluation and Narrow band imaging with Fibre-optic laryngoscopy.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\u003cp\u003eThe distribution of variables across the two study groups was compared using various statistical tests, including the Chi-Square test or Fisher's exact probability test for categorical variables, independent sample t-test for normally distributed continuous variables. A p-value of less than 0.05 was considered statistically significant throughout the study. The entire dataset was analyzed using Statistical Package for Social Sciences (SPSS version 22.0, IBM Corporation, NY; USA) for MS Windows.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eIn this study out of 100 subjects, majority of subjects (46.0%) were between 31-40 years old. The mean age was 46.65 \u0026plusmn;11.58 years. The study population showed a predominance of males, accounting for 64 subjects (64.0%), while females comprised 36 subjects (36.0%), indicating a male preponderance with a male-to-female ratio of approximately 1.78:1.\u003c/p\u003e\n\u003cp\u003eFundamental Frequency of vocal cords in males found on stroboscopy was between the range of 110-110 Hz in 47 subjects (73.4% of males) and between 111- 120 in 17 cases (26.6% of males). In females, Fundamental Frequency was in the range of 200-210 in 31 subjects (86.1% of females) and 5 subjects (13.9% of females) \u0026nbsp;had fundamental frequency in the range of 220-220 Hz as shown in Table 1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTables\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1:\u003c/strong\u003e \u003cstrong\u003eDistribution of Fundamental frequency of subjects studied.\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFundamental frequency Range (Hz)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNo. of subjects\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e% of subjects\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003eMale (n=64)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003e100 \u0026ndash; 110\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e73.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003e111 \u0026ndash; 120\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e26.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003eFemale (n=36)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003e200 \u0026ndash; 210\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e86.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003e211 \u0026ndash; 220\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e13.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eThe majority of cases (90.0%) had complete glottic closure, indicating normal vocal cord function, while a smaller proportion (10.0%) had incomplete closure, suggesting potential vocal cord dysfunction as shown in Table 2.\u003c/p\u003e\n\u003cp\u003eOn stroboscopy, most cases (86.0%) had symmetrical vocal cord vibration, indicating normal anatomy, whereas a minority (14.0%) had asymmetrical vocal cord vibration, which could be indicative of underlying pathology as shown in Table 2.\u003c/p\u003e\n\u003cp\u003ePeriodic vocal cord vibration was observed in the majority of cases (92.0%), suggesting normal vocal cord function, while a small proportion (8.0%) had aperiodic vibration, indicating potential vocal cord dysfunction as shown in Table 2.\u003c/p\u003e\n\u003cp\u003eThe mucosal waves were normal in most cases (77.0%), while alterations in the wave pattern were observed in some cases, including reduced (20.0%), increased (2.0%), and absent (1.0%) mucosal waves as shown in Table 2.\u003c/p\u003e\n\u003cp\u003eThe amplitude of vocal cord vibration was normal in most cases (77.0%), while some cases had reduced (21.0%) or increased (2.0%) amplitude, indicating potential variations in vocal cord function as shown in Table 2.\u003c/p\u003e\n\u003cp\u003eThe Narrow band imaging findings showed a predominance of Type II (63.0%), followed by Type I (22.0%), Type III (13.0%), and Type Vc (2.0%). Type Vc \u0026nbsp;[Figure 1]is suggestive of malignancy as shown in Table 2.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2:\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eDistribution of structural changes of vocal cords in subjects of smoking\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"640\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNo. of cases\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e% of cases\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGlottic closure pattern\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eComplete\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e90.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eIncomplete\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e10.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSymmetry\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eAsymmetrical\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e14.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eSymmetrical\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e86.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePeriodicity\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eAperiodic\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e8.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003ePeriodic\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e92.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMucosal wave\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eNormal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e77.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eReduced\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e20.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eIncreased\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eAbsent\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAmplitude\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eNormal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e77.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eReduced\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e21.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eIncreased\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNarrow band imaging type\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eType I\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e22.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eType II\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e63.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eType III\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e13.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 195px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eVc\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 144px;\"\u003e\n \u003cp\u003e2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eIn this study, various structural pathologies were seen in the subjects including bilateral keratosis (5.0%) [Figure 2], increased vascularity (3.0%), unilateral keratosis (3.0%), ulcerative growth (3.0%) [Figure 3], edematous cord (3%), \u0026nbsp;and other findings such as vocal cord nodules[Figure 4], sulcus vocalis [Figure 5], leukoplakia, and Reinke\u0026apos;s edema, each occurring in a smaller proportion of subjects. While 76.0% of subjects had normal vocal cords without any pathology.\u003c/p\u003e\n\u003cp\u003eAmong males, the distribution of structural findings of vocal cords was compared across two fundamental frequency ranges (100-110 and 111-120), and the results showed no statistically significant association between lower fundamental frequency and vocal cord findings (p-value = 0.410). The majority of cases in both frequency groups had normal vocal cords, with 72.3% in the 100-110 group and 82.4% in the 111-120 group.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAmong females, the distribution of structural findings of vocal cords was compared across two fundamental frequency ranges (200-210 and 211-220), and the results showed no statistically significant association between lower fundamental frequency and vocal cord findings (p-value = 0.291). The majority of female cases had normal vocal cords, with 77.4% in the 200-210 frequency group and 80.0% in the 211-220 group.\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eCigarette smoking causes negative effects on various systems of our body. Inhaling tobacco smoke leads to inflammation of the airways, resulting in increased mucus production and irritation.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] Previously studies showing the effect of smoking through cadaveric study of vocal cords or through acoustic parameters have been done, but literature search did not reveal any study on evaluating effect of smoking on structure and function of vocal cords both. This study was designed with the purpose to evaluate the effects of smoking on the vocal cord structure and function in adult patients in a tertiary care centre.\u003c/p\u003e\u003cp\u003eIn this study, Fundamental Frequency of vocal cords in males found on stroboscopy was between the range of 110\u0026ndash;110 Hz in 47 subjects (73.4% of males) and between 111\u0026ndash;120 in 17 cases (26.6% of males). In females, Fundamental Frequency was in the range of 200\u0026ndash;210 in 31 subjects (86.1% of females) and 5 subjects (13.9% of females) had fundamental frequency in the range of 220\u0026ndash;220 Hz. More subjects had fundamental frequencies on the lower range.\u003c/p\u003e\u003cp\u003eIn the study conducted by \u003cb\u003eAyoub M et al\u003c/b\u003e, it shows that mean fundamental frequency was low in cigarette smokers (\u003cem\u003eM\u003c/em\u003e\u0026thinsp;=\u0026thinsp;104.47, SD\u0026thinsp;=\u0026thinsp;14.03) than nonsmokers (\u003cem\u003eM\u003c/em\u003e\u0026thinsp;=\u0026thinsp;119.43, SD\u0026thinsp;=\u0026thinsp;17.19) (HSD: \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001).[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eThe study by \u003cb\u003eGonzalez et al\u003c/b\u003e, states that smokers had mean fundamental frequency (Fo) lower than non-smokers. P value in men was \u0026lt;\u0026thinsp;0.10 and in women was \u0026lt;\u0026thinsp;0.01.[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e\u003cp\u003e\u003cb\u003eTuhanioglu et al\u003c/b\u003e in his study stated that there was no significant difference between the fundamental frequency in conventional cigarettes, e- cigarettes and control group.[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eIn the Meta-analysis by \u003cb\u003eByeon et al\u003c/b\u003e, there was a significant difference in the \u0026lsquo;intermediate\u0026rsquo; level of effect size of fundamental frequency (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001).[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eIn terms of functional changes in the vocal cords, fundamental frequency was seen to be lower in smokers in this study. Other functional changes were seen in few subjects involving 10% subjects had incomplete glottic closure, 14% subjects showed asymmetrical vocal cord vibration and 8% subjects had aperiodic vocal cord vibrations, 33% subjects showed abnormal mucosal waves and abnormal amplitude.\u003c/p\u003e\u003cp\u003e\u003cb\u003eByeon H et al\u003c/b\u003e in his study stated that there was no association between functional voice disorders and smokers.[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eThe study by \u003cb\u003eGonzalez et al\u003c/b\u003e, involved a combination of voice parameters of jitter, shimmer and noise to harmonic ratio, to evaluate the effect of smoking on vocal cords. These parameters showed possible neurological effects on voice by smoking.[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e\u003cp\u003e\u003cb\u003eTuhanioglu et al\u003c/b\u003e, in his study evaluated subjective and objective voice analysis to detect functional changes in vocal cords. His study shows jitter, F0 and shimmer percentage values shows no significant difference between the smokers and non-smokers. However, significant difference was seen in shimmer dB and HNR depicting functional voice changes. [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eIn the meta-analysis by \u003cb\u003eByeon et al\u003c/b\u003e, it is stated that smoking had moderate and significant effects on the VHI, F0 of voice, MPT, and physical functions of vocal cords.[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eIn this study, various structural pathologies were seen in the subjects including bilateral keratosis (5.0%), increased vascularity (3.0%), unilateral keratosis (3.0%), ulcerative growth (3.0%), edematous cord (3%), and other findings such as vocal cord nodules, sulcus vocalis, leukoplakia, and Reinke's edema occurred in a smaller proportion. 24% of subjects had abnormal vocal cords with organic voice disorders, while 76.0% of subjects had normal vocal cords without any pathology.\u003c/p\u003e\u003cp\u003eIn the study by \u003cb\u003eByeon H et al\u003c/b\u003e, correlation of organic voice disorders with past smokers was 3-times higher than nonsmokers (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05), and was 3.2-times higher in current smokers as compared to non-smokers (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05).[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eStudy by \u003cb\u003eKelleher et al\u003c/b\u003e, is a postmortem study of microstructure of vocal cords which shows smoker subjects had less fibers in mid-membranous region than at the anterior/posterior regions but non-smokers had normalized fiber density depicting influence of smoking on direction and degree of microstructure heterogeneity in vocal fold ligament.[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/p\u003e\u003cp\u003e\u003cb\u003eHirabayashi et al\u003c/b\u003e conducted a postmortem study on vocal cords to detect structural changes in smokers and drinkers which depicted significant difference in the thickness of the epithelium of vocal cords and supraglottic\u003c/p\u003e\u003cp\u003eregion in smoking and drinking patients, as compared to non-smokers and non-drinkers.[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eAmong both males and females, the distribution of structural findings of vocal cords was compared across two fundamental frequency ranges, and the results showed no statistically significant association between lower fundamental frequency and vocal cord findings. This correlation was done as lower fundamental frequency in smokers was found in various previous articles[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e][\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e][\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] and considering it as a constant in smokers, organic voice disorders in smokers were studied but no correlation was found between them.\u003c/p\u003e\u003cp\u003eThe Narrow band imaging findings showed a predominance of Type II (63.0%), followed by Type I (22.0%), Type III (13.0%), and Type Vc (2.0%). Type Vc is suggestive of malignancy. This suggests that organic voice disorders were seen in very few subjects of smoking.\u003c/p\u003e\u003cp\u003eIn the study by \u003cb\u003eShibuya et al\u003c/b\u003e, Narrow band imaging was used to detect angiogenic squamous dysplasia in lungs in smokers.[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eThough previous studies showing the effect of smoking through cadaveric study of vocal cords or through acoustic parameters have been done, no study was conducted on evaluating effect of smoking on structure and function of vocal cords both. Use of stroboscopy to evaluate the functional changes in vocal cords was done for the first time, in previous studies functional changes were evaluated by acoustic parameters.\u003c/p\u003e\u003cp\u003eStroboscopy helps in detecting the vibratory characteristics of vocal cords depicting function and also detects organic lesions by mucosal wave characteristics.[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] Narrow band imaging detects neo-vascularisation which is feature of squamous cell carcinoma by using optical filter filtering white light into wavelengths of blue and green. It helps in detecting premalignant and malignant lesions.[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eNarrow band imaging to detect lesions in larynx in smokers was not studied previously. In this pilot study, stroboscopy and NBI is used to study structural and functional changes in vocal cords due to smoking.\u003c/p\u003e\u003cp\u003eThis study helps in early detection of development of changes in vocal cords. It aids to prevent complications and development of malignancies and if possible generate awareness among the population regarding the harmful effects of smoking on vocal health and encourage people in eliminating this habit.\u003c/p\u003e\u003cp\u003eFew limitations of the study are that, sample size is small, confounding factors such as laryngopharyngeal reflux disease, stress and consumption of spicy food were not taken into consideration in this study and one time testing was done without further follow up. It was an cross-sectional study, hence comment on a direct cause and effect between smoking and voice disorders cannot be done.\u003c/p\u003e\u003cp\u003eIn future studies, combined study involving acoustic voice analysis along with stroboscopy and NBI can be done. Enrolling large number of subjects with bigger sample size, study comparing smokers and non-smokers by using a control group can be considered. Randomised control trials involving interventions such as Point-of-care ultrasound (POCUS) can be used for future studies.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn this study, our results show that smoking has an effect on the function of vocal cords by lower fundamental frequency in majority of the subjects. But other functional parameters were abnormal only in few subjects. Causality of organic voice disorders and smoking was not established.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cul type=\"disc\"\u003e\n \u003cli\u003eEthics approval and consent to participate- Taken. Ethical Approval Reference Number: BVDUMC/IEC/15/25-26\u003c/li\u003e\n \u003cli\u003eConsent for publication- Taken\u003c/li\u003e\n \u003cli\u003eAvailability of data and material- Available\u003c/li\u003e\n \u003cli\u003eCompeting interests- No competing interests\u003c/li\u003e\n \u003cli\u003eFunding- No Funding required\u003c/li\u003e\n \u003cli\u003eAcknowledgements- The authors thank all the participants in the research.\u003c/li\u003e\n\u003c/ul\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eDr. Krutika Yadav: study design, definition of intellectual content, literature search, data acquisition, statistical analysis, manuscript preparation, guarantorDr. Prasun Mishra: Editing data, Proof reading and revision of data. Concept, manuscript editingDr. Chethana R: data analysis, manuscript review\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eGupta S, Kumar V, Gupta P. A comprehensive study on the harmful effects of the smoking on human beings. In: Challenges in Information, Communication and Computing Technology [Internet]. London: CRC Press; 2024. p. 577\u0026ndash;82. Available from: https://www.taylorfrancis.com/books/9781003559085/chapters/10.1201/9781003559085-99\u003c/li\u003e\n\u003cli\u003eKelleher JE, Siegmund T, Chan RW. Collagen microstructure in the vocal ligament: Initial results on the potential effects of smoking. Laryngoscope. 2014;124(9). \u003c/li\u003e\n\u003cli\u003eGonzalezabcdeg J, Carpibcdef A. Early effects of smoking on the voice: A multidimensional study [Internet]. Available from: http://www.MedSciMonit.com/pub/vol_10/no_12/4738.pdf\u003c/li\u003e\n\u003cli\u003eChethana R, Mishra P, Kaushik M, Jadhav R, Dehadaray A. Effect of Smoking on Nasal Mucociliary Clearance. Indian Journal of Otolaryngology and Head and Neck Surgery. 2022 Oct 1;74:956\u0026ndash;9. \u003c/li\u003e\n\u003cli\u003eAyoub MR, Larrouy-Maestri P, Morsomme D. The Effect of Smoking on the Fundamental Frequency of the Speaking Voice. Journal of Voice. 2019 Sep 1;33(5):802.e11-802.e16. \u003c/li\u003e\n\u003cli\u003eGonzalezabcdeg J, Carpibcdef A. Early effects of smoking on the voice: A multidimensional study [Internet]. Available from: http://www.MedSciMonit.com/pub/vol_10/no_12/4738.pdf\u003c/li\u003e\n\u003cli\u003eTuhanioğlu B, Erkan SO, \u0026Ouml;zdaş T, Derici \u0026Ccedil;, T\u0026uuml;z\u0026uuml;n K, Şenkal \u0026Ouml;A. The Effect of Electronic Cigarettes on Voice Quality. Journal of Voice. 2019 Sep 1;33(5):811.e13-811.e17. \u003c/li\u003e\n\u003cli\u003eByeon H, Cha S. Evaluating the effects of smoking on the voice and subjective voice problems using a meta-analysis approach. Sci Rep. 2020 Dec 1;10(1). \u003c/li\u003e\n\u003cli\u003eByeon H. Relationships among smoking, organic, and functional voice disorders in korean general population. Journal of Voice. 2015 May 1;29(3):312\u0026ndash;6. \u003c/li\u003e\n\u003cli\u003eKelleher JE, Siegmund T, Chan RW. Collagen microstructure in the vocal ligament: Initial results on the potential effects of smoking. Laryngoscope. 2014;124(9). \u003c/li\u003e\n\u003cli\u003eHirabayashi H, Koshii K, Uno K, Ohgaki H, Nakasone Y, Fujisawa T, et al. Laryngeal Epithelial Changes on Effects of Smoking and Drinking. Auris Nasus Larynx. 1990;17(2):105\u0026ndash;14. \u003c/li\u003e\n\u003cli\u003eShibuya K, Hoshino H, Chiyo M, Iyoda A, Yoshida S, Sekine Y, et al. High magnification bronchovideoscopy combined with narrow band imaging could detect capillary loops of angiogenic squamous dysplasia in heavy smokers at high risk for lung cancer [Internet]. Available from: www.thoraxjnl.com\u003c/li\u003e\n\u003cli\u003eMehta DD, Hillman RE. Current role of stroboscopy in laryngeal imaging. Curr Opin Otolaryngol Head Neck Surg. 2012 Dec;6(20):429\u0026ndash;36. \u003c/li\u003e\n\u003cli\u003eSargunaraj JJE, Mathews SS, Paul RR, Michael RC, Thomas M, Gowri M, et al. Role of Narrow Band Imaging in Laryngeal Lesions: A Prospective Study from Southern India. Indian Journal of Otolaryngology and Head and Neck Surgery. 2022 Dec 1;74:5127\u0026ndash;33. \u003c/li\u003e\n\u003c/ol\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":"the-egyptian-journal-of-otolaryngology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [The Egyptian Journal of Otolaryngology](https://ejo.springeropen.com/)","snPcode":"43163","submissionUrl":"https://submission.springernature.com/new-submission/43163/3","title":"The Egyptian Journal of Otolaryngology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Smoking, stroboscopy, narrow band imaging, vocal cords, larynx","lastPublishedDoi":"10.21203/rs.3.rs-7379371/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7379371/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e: Inhaling tobacco smoke leads to inflammation of airways. Previous studies have focused on effect of smoking through cadaveric study of vocal cords and study of acoustic parameters. However, literature search did not reveal any study on evaluating effect of smoking on structure and function of vocal cords both. This study was designed with purpose to evaluate effects of smoking on the vocal cord structure and function in adult patients.\u003c/p\u003e\n\u003cp\u003eThis study involves 100 participants who came to ENT OPD with complaints related to throat and history of smoking for more than 5 years with at least 5 cigarettes/day. These participants were evaluated for vocal cord function and structure by Stroboscopic evaluation and Narrow band imaging(NBI) with Fibre-optic laryngoscopy\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003eThis study included 100 subjects with mean age of 46.65 ±11.58 years and showed male predominance.\u003c/p\u003e\n\u003cp\u003eFundamental Frequency(Fo) of vocal cords in males was between range of 110-110 Hz in 47 subjects(73.4% of males) and between 111- 120 in 17 cases(26.6% of males). In females, Fundamental Frequency was in range of 200-210 in 31 subjects(86.1% of females) and in 5 subjects(13.9% of females) in range of 220-220 Hz. Among functional findings seen on stroboscopy, 10 subjects had incomplete glottic closure, 14 subjects had asymmetrical and 8 subjects had aperiodic vocal cord vibrations. In terms of mucosal waves, reduced(20.0%), increased(2.0%), and absent(1.0%) mucosal waves were seen in subjects with abnormal mucosal waves with rest of subjects having normal findings. While reduced(21.0%) and increased(2.0%) amplitude was seen in subjects with abnormal amplitudes and rest of subjects having normal findings. Narrow band imaging findings showed a predominance of Type II(63.0%), followed by Type I(22.0%), Type III(13.0%), and Type Vc(2.0%). In this study, various structural pathologies were seen in subjects including bilateral keratosis(5.0%), increased vascularity(3.0%), unilateral keratosis(3.0%), ulcerative growth(3.0%), edematous cord(3%), and few other findings in few subjects.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003eSmoking has effect on function of vocal cords depicted by lower fundamental frequency. Other functional parameters were abnormal only in few subjects. Organic voice disorders were found in only few smokers.\u003c/p\u003e","manuscriptTitle":"A study of the effect of smoking on vocal cord structure and function evaluated by narrow band imaging and stroboscopy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-15 10:23:03","doi":"10.21203/rs.3.rs-7379371/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-09-19T20:13:12+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-17T20:04:08+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-13T08:48:20+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"325419561128613858123385121054495028087","date":"2025-09-07T21:01:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"267110617643333190361843186287798117092","date":"2025-09-07T20:57:44+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-05T20:54:21+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-09-01T09:49:23+00:00","index":"","fulltext":""},{"type":"submitted","content":"The Egyptian Journal of Otolaryngology","date":"2025-08-30T12:31:05+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"the-egyptian-journal-of-otolaryngology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [The Egyptian Journal of Otolaryngology](https://ejo.springeropen.com/)","snPcode":"43163","submissionUrl":"https://submission.springernature.com/new-submission/43163/3","title":"The Egyptian Journal of Otolaryngology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"fb2a7fc4-469d-4d01-b48a-15c3ad32909d","owner":[],"postedDate":"September 15th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-12-05T14:23:22+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-15 10:23:03","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7379371","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7379371","identity":"rs-7379371","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}