Risk Factors for Early-Onset Colorectal Cancer: The Role of Diet, Lifestyle and Obesity

Risk Factors for Early-Onset Colorectal Cancer: The Role of Diet, Lifestyle and Obesity | 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 Risk Factors for Early-Onset Colorectal Cancer: The Role of Diet, Lifestyle and Obesity Jacqueline Keenan, Oliver Waddell, Andrew McCombie, Alma Vineetha joy, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7707153/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 12 You are reading this latest preprint version Abstract Background. Colorectal cancer (CRC) is the third most commonly diagnosed cancer globally, and remains the second leading cause of cancer-related mortality. The incidence of early-onset colorectal cancer (EOCRC) among young adults before the age of 50 is rising worldwide, with EOCRC rates in New Zealand increasing by 26% per decade overall and by 16% in Maori. The underlying causes remain unclear although environmental and lifestyle factors are suspected contributors. The study investigated associations between known risk factors and the development of CRC in a New Zealand population, with a focus on tumour location and age at diagnosis. Methods. A retrospective case-control study was conducted in Canterbury, New Zealand comparing recently diagnosed CRC patients (n = 304) with age- and sex-matched community controls (n = 627). Data on diet, obesity, physical activity, smoking, alcohol consumption, and family history were collected via a self-reported questionnaire. Logistic regression was used to assess associations between risk factors, tumour location, and age at diagnosis. Results. CRC patients had significantly higher rates of obesity (BMI ≥ 30 kg/m²; OR 1.47, p = 0.020), positive family history (OR 1.49, p = 0.040), sugary drink (OR 1.78, p < 0.001) and fast food consumption (OR 1.57, p = 0.007), heavy alcohol intake (OR 3.05, p = 0.004), and lower levels of physical activity (OR 1.51, p = 0.011) compared with controls. Left-sided tumours (69.1% of cases) were significantly associated with obesity (OR 1.57, p = 0.015), family history (OR 1.57, p = 0.042), physical inactivity (OR 1.56, p = 0.016), and alcohol use (OR 2.46, p < 0.001). Processed meat consumption was significantly associated with EOCRC (OR 2.70, p = 0.019). Conclusions. Modifiable factors, particularly sugary drink and fast food intake, obesity, alcohol use, and physical inactivity significantly associate with CRC risk in New Zealand, particularly for left-sided and early-onset disease. Familial predisposition further compounds this risk. These findings highlight the need for targeted prevention strategies that combine lifestyle modification with genetic risk assessment colorectal cancer diet lifestyle obesity Background Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide, with 1.9 million new cases reported in 2020. It is also the second leading cause of cancer-related mortality. The incidence of CRC increases with age and the majority of CRC cases are sporadic. Migration studies have shown that individuals relocating from low- to high-risk regions before the age of 30 tend to adopt the CRC risk profile of the host country ( 1 , 2 ). Notably, a marked increase in CRC incidence and mortality has been observed within a single generation in many low- and middle-income countries ( 3 ). Furthermore, the incidence of CRC among individuals under 50 years of age is rising globally ( 4 , 5 ). In the United States, colorectal cancer is the leading cause of cancer death in men under 50, and the second most common cause of cancer death in women under 50. A similar trend is evident in New Zealand, where the incidence of early-onset colorectal cancer is increasing by an average of 26% per decade. Among the Māori population, the rate of increase is even higher, reported at approximately 36% per decade ( 6 ). EOCRC differs from late-onset CRC as it predominantly involves left-sided lesions, particularly in the rectum, rectosigmoid junction, and sigmoid colon ( 7 , 8 ). While the underlying causes of these epidemiological shifts remain unclear ( 9 ), the presence of birth cohort effects suggests evolving exposure to environmental risk factors over time ( 10 , 11 ). The specific drivers of carcinogenesis, especially among younger New Zealanders, have yet to be fully elucidated ( 12 ). A number of loosely associated lifestyle factors such as diet-associated obesity, sedentary lifestyles, tobacco use, alcohol consumption and the westernisation of diets are increasingly common as well as shared across generations of individuals worldwide ( 13 ). These extrinsic influences may contribute to carcinogenesis by inducing aberrant DNA hypermethylation, which can promote deleterious genetic mutations that drive progression through the adenoma–carcinoma sequence ( 14 ). Such changes may occur regardless of age, suggesting that shifting lifestyle behaviours likely play a substantial role in the rising incidence of early-onset CRC. The primary objective of this study was to evaluate dietary and lifestyle risk factors in patients recently diagnosed with CRC, compared with age-matched healthy controls. A secondary aim was to explore associations between these risk factors, tumour location, and patient age Methods Study design . This retrospective, case-control study compared putative risk factors between CRC patients and healthy controls within defined age groups. The sample size was pragmatically determined. Approximately 300 people in the Canterbury region of New Zealand receive a CRC diagnosis annually; this study sought to recruit as many of these patients as possible within this timeframe. This sample was anticipated to provide sufficient power for univariate and multivariate logistic regression analyses to identify independent CRC risk factors. Two community-based healthy controls were selected for each patient, matched by age range and sex. Study population . All patients over 18 years of age presenting at Christchurch Hospital with a new diagnosis of colorectal adenocarcinoma were verbally invited to participate in the study. Controls were randomly selected from the electoral role within the same catchment area, matched for age and sex, and supplemented by community recruitment using the same criteria. Ethics approval and consent to participate. The University of Otago Human Ethics Committee approved the study (H20/043) and informed consent was obtained from all participants who completed the questionnaire (online or in print), which is in line with the Declaration of Helsink Baseline characteristics of participants by case and control status. Participants reported their age, sex, weight and height. Familial CRC risk was assessed by querying immediate family history (parent or sibling diagnosed with CRC). Pathology reports of CRC patients were reviewed to determine tumour anatomical location. Assessment of lifestyle factors. Participants were surveyed regarding the frequency of consumption of sugary drinks, fast food, red and processed meat. Consumption at least weekly was used as a cut-off for risk assessment. Regular physical activity was defined as at least 2-3 times of 30 minutes of moderate intensity exercise weekly. Smoking history included age at initiation, the number of cigarettes smoked daily and cessation age if applicable. Participants were classified as smokers if currently smoking or former smokers with ≥ 30 pack years; other were considered non-smokers (13). Alcohol consumption was categorised by frequency (low: <1-2 times/week; medium: 1-2 times/week; high: 3-4 times/week) (15) and volume (light: 1 drink/day [12.5 g/day ethanol]; moderate: 2-3 drinks/day [12.6–49.9 g]; heavy: ≥4 drinks/day [≥50 g/day of ethanol] (16). Statistical analysis. Logistic regression models (SPSS version 29.0.2.0) compared cases and controls in terms of the putative risk factors, expressed as odds ratios (OR) with 95% confidence intervals. Analyses controlled for age and sex unless these were variables of interest. Interaction terms tested whether risk factors differentially affected tumour location (left- vs. right-sided) or age (<50 v ≥50years). Results Of 336 patients with a preliminary diagnosis of CRC invited to take part in the study, 304 completed the questionnaire. The control group comprised 627 participants (26.2% participation rate). Three patients lacking confirmed adenocarcinoma and six controls with a CRC history were excluded (Figure 1). Median ages were 69 (range 29-91) for cases and 72 (range 28-91) for controls (p=0.138); 52% were male (p=0.818, Table 1). There were 41 cases and 80 controls aged < 50 years, and 263 cases and 547 controls aged 50 years and over (Table 3). No significant sex distribution differences were noted between cases and controls in either age cohort, and while controls in the older group were marginally older, this difference was not significant. Median BMI was 26.3 kg/m 2 (cases range 12.9-44.6; controls 14.8-45.6). Using a BMI ≥30 kg/m 2 as the cut-off for obesity, more CRC patients were obese compared to controls (p=0.020, Table 1). Cases were also more like to report immediate family history of CRC (p=0.04, Table 1). Several lifestyle factors were associated with increased CRC risk (Table 2). Cases reported high regular consumption of sugary drinks and fast food compared to matched controls (OR 1.78, p<0.001 and OR 1.57, p=0.007, respectively). Medium to high frequency and heavy alcohol consumption were more frequent among cases (OR 2.06, p=0.004), whereas controls engaged more in regular physical activity (OR 1.51, p=0.011). Given the predominance of left-sided tumours (69.1%) (Table 1), tumour location associations were examined (Table 3). Right sided cancers were more common in women; left-sided in men (p=0.04). Younger patients more frequently presented with left-sided disease (p<0.01). Obesity was a significant risk factor for left-sided cancer (OR 1.57, p=0.015); right-sided cases were heavier than controls, but not significantly (OR 1.32). Family history of CRC was associated with left-sided but not right-sided cancers (OR 1.57, p=0.042). Regular sugary drink and fast food consumption increased CRC risk regardless of tumour location. However, no association was found between meat consumption (red or processed) or smoking and tumour site (Table 3). Physical inactivity increased risk of left-sided disease (OR 1.56, p=0.016). Alcohol-related risk was higher for distal and rectal cancers (OR 2.46, p<0.001) compared to the proximal colon (OR 0.97), even with reduced drinking frequency. When stratified by age, obesity was a significant risk factor among older cases (≥50 years) (OR 1.51, p=0.021). BMI was also notably higher in the younger (˂50 years) cases (OR 1.38) but not a significant risk factor when compared to the control group (Table 4). Sugary drink (OR 1.81, p<0.001) and fast food (OR 1.67, p=0.004) consumption were higher among older patients than controls. Younger patients also consumed these more frequently (OR 1.74 and 1.41, respectively, but differences were non-significant. Processed meat intake was associated with early-onset CRC (OR 2.7, p=0.019) that differed significantly by age group (p=0.02). Older patients exercised less than matched controls (OR 1.70, p=0.002). Heavy alcohol consumption was significantly associated with CRC among older patients (OR 2.06, p=0.009). While smoking status was not significantly associated with CRC overall (p=0.19; Table 2), younger cases were more likely to identify as former or current smokers (OR 4.32) though numbers were very small. Vaping and use of other tobacco products were uncommon (seven cases and six controls). Discussion This study identifies the consumption of sugary drinks and fast food, physical inactivity, heavy alcohol intake, and obesity as significant extrinsic risk factors for CRC in New Zealand. The elevated obesity rates observed align with recent reports of increased adiposity-related cancers in the country (17). Lifetime overweight or obesity is increasingly recognised as a major contributor to CRC risk (18). The high prevalence of obesity among New Zealand children and adolescents (19) may be contributing to the rising incidence of CRC, particularly early-onset disease (20). It remains unclear whether obesity itself or the behaviours leading to obesity, such as dietary patterns and sedentary lifestyles, have the greater impact on carcinogenesis. The familial clustering of CRC observed in this study may reflect shared lifestyle exposures across generations in addition to inherited genetic susceptibility. High sugar intake has been shown to increase CRC risk through its effects on blood glucose and insulin levels (21-23). Mechanistically, excessive sugar that surpasses the absorptive capacity of the small intestine undergoes fermentation in the colon, potentially compromising mucosal barrier function, particularly in the proximal colon (24, 25). In contrast, the consumption of high-fat fast food promotes the expansion of bile-tolerant, sulphate-reducing bacteria, which produce genotoxic hydrogen sulphide in the colon (26-28). Alcohol-related CRC risk appears to be dose-dependent and may be mediated through alterations in the gut microbiome, resulting in the production of alcohol-derived carcinogenic metabolites (16, 29-31). Physical inactivity may increase CRC risk by prolonging colonic transit time and altering microbiota metabolism toward protein catabolism, leading to an accumulation of genotoxic metabolites (32, 33). Risk factors also exhibited subsite-specific associations. Consistent with prior studies (34)[33], physical inactivity, obesity, sugary drink intake, and alcohol consumption were each associated with increased risk of left-sided tumours (35-38). Interestingly, fast food consumption was linked to right-sided disease, which may reflect the high sugar content typical of fast food meals in New Zealand, along with the associated expansion of sulphate-metabolising bacteria that predispose to distal disease (25, 39, 40). Familial CRC history was most strongly associated with left-sided tumours, again suggesting that shared lifestyle factors may influence tumour location. Age-stratified analyses revealed that processed meat consumption was significantly associated with early-onset CRC, consistent with its classification as a Group 1 carcinogen (41). Processed meats may promote carcinogenesis via nitrate exposure and sulphur-metabolising bacteria generating genotoxic compounds (40, 42, 43). Interestingly, obesity, sugary drink and fast food consumption, heavy alcohol use, and physical inactivity were more strongly associated with CRC in older participants, but not in younger ones. This may reflect the smaller sample size of the early-onset disease cohort or may signal an overall upward shift in lifestyle risk behaviours among younger New Zealanders—whose age-matched controls reported similarly high consumption of sugary drinks and fast food (19, 44). The younger cohort also demonstrated heavier and more frequent alcohol intake, indicating another potential risk factor for early-onset disease (45). Although smoking is a well-established risk factor for CRC, it demonstrated a non-significant trend toward increased risk in this study. Tobacco carcinogens are known to induce DNA damage, epigenetic alterations, and pro-inflammatory changes that promote colorectal carcinogenesis (46). The absence of statistical significance in our findings may be attributable to limited sample size or variability in smoking intensity, duration, and timing. Additionally, the increasing shift from traditional cigarette smoking to vaping introduces further complexity, as the long-term oncogenic potential of e-cigarette use remains poorly understood. Future studies incorporating objective biomarkers of tobacco exposure, along with molecular profiling of tumours, are needed to better characterise the role of smoking and related behaviours in the aetiology of early-onset CRC. This study has several limitations. Data on lifestyle and dietary behaviours were self-reported, introducing the possibility of recall bias. Longitudinal measures of obesity and sedentary behaviour (particularly relevant to early-onset and distal CRC) were not available (47-50). Additionally, protective dietary factors such as fibre intake, which is known to influence colonic transit time and reduce CRC risk, were not assessed (51). Despite these limitations, the study’s population-based design and inclusion of well-matched community controls enhance its generalisability. In summary, these findings suggest that evolving environmental and lifestyle exposures, combined with familial predisposition, contribute to the increasing incidence of early-onset CRC both in New Zealand and globally (6, 52, 53). Targeted prevention strategies, particularly those aimed at reducing sugary drink and fast food consumption, promoting physical activity, managing obesity, and curbing alcohol use, are urgently required, especially among younger populations. Incorporating both family history and modifiable lifestyle factors into CRC risk stratification models may improve early detection and facilitate personalised screening protocols Conclusion This study reinforces the critical role of modifiable lifestyle factors including diet, obesity, physical inactivity, and alcohol consumption in shaping colorectal cancer risk, particularly in young people. The significant associations observed with age, obesity, alcohol consumption and a positive family history of CRC with left-sided disease, as well as the observation of an age-related effect with regards processed meat consumption, collectively underscore the likely multifactorial nature of carcinogenesis in younger populations. These findings support the need for a comprehensive, population-level approach to CRC prevention that combines behavioural interventions with genetic risk assessment. Early identification of high-risk individuals and the implementation of targeted public health strategies promoting healthier lifestyle behaviours are essential to reversing the rising incidence of early-onset CRC. Ongoing research is vital to further elucidate the complex interplay between environmental exposures, genetic susceptibility, and tumour biology. Such insights will be key to refining prevention efforts and developing effective, risk-adapted screening strategies. Declarations Ethics approval and consent to participate. The University of Otago Human Ethics Committee approved the study (H20/043) and informed consent was obtained from all participants who completed the questionnaire (online or in print). Consent for publication. Not applicable. Availability of data and materials. The datasets generated and/or analysed during the current study are not publicly available due to data sovereignty requirements but are available from the corresponding author on reasonable request explaining how the data will be used . Competing interests. The authors declare they have no competing interests. Funding. Authors contributions. JK and FF conceptualised the study. JK, OW, AVJ, JS and AMcC were involved in the recruitment of study participants. CF and AMcM formally analysed the data. JK interpreted the analysis and wrote the original draft of the manuscript that FF reviewed and edited. All authors read and approved the final manuscript. Acknowledgements. 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Tables Table 1 Baseline characteristics of participants by case and control status Characteristics Controls (%) Cases b (%) Odds ratio (95% CI) a p-value Males, n (%) 322/627 (51.4) 160/304 (52.6) 1.03 (0.78–1.36) 0.818 Median age (range) 72 (28–91) 69 (29–91) 0.99 (0.98–1.002) 0.138 Median BMI (range) 26.3 (12.9–44.6) 26.3 (14.8–45.6) 1.02 (0.99–1.05) 0.146 BMI ≥ 30 (kg/m 2 ), n (%) 126/606 (20.8) 80/285 (28.1) 1.47 (1.06–2.04)* 0.020 Immediate family CRC, n (%) 82/627 (13.1) 54/304 (17.8) 1.49 (1.02–2.17)* 0.040 Tumour location (n) Right (proximal colon) - 94 (30.9%) Left (distal colon/rectum) - 210 (69.1%) a , Odds ratios adjusted for age and sex; b , the one person with CRC on both sides allocated to proximal only; BMI, body mass index; CRC, colorectal cancer; n, number of valid responses. *, p < 0.05 Table 2 Association between lifestyle factors and colorectal cancer by case and control status Lifestyle factor Controls n (%) Cases n (%) Odds ratio (95% CI) p-value Sugary drinks (weekly or more) 131/627 (20.9%) 98/304 (32.2%) 1.78 (1.30–2.43)* < 0.001 Fast food (weekly or more) 131/627 (20.9%) 91/304 (29.9%) 1.57 (1.13–2.16)* 0.007 Red meat (weekly or more) 517/627 (82.5%) 257/304 (84.5%) 1.18 (0.81–1.71) 0.397 Processed meat (weekly or more) 331/627 (52.8%) 166/304 (54.6%) 1.05 (0.80–1.40) 0.714 Physical inactivity a 132/627 (21.1%) 84/304 (28.6%) 1.51 (1.10–2.07)* 0.011 Current high frequency b and heavy alcohol consumption c 12/606 (2.0%) 17/289 (5.9%) 3.05 (1.43–6.52)* 0.004 Current medium to high frequency d and heavy alcohol consumption c 37/606 (6.1%) 35/289 (12.1%) 2.06 (1.25–3.40)* 0.004 Current or former (≥ 30 pack years) smoker 65/595 (10.9%) 39/284 (13.7%) 1.33 (1.43–6.52) 0.193 Odds ratios adjusted for age and sex; a , less than 2–3 times of 30 minutes moderate intensity exercise/week; b , three or more times a week; c , four or more drinks per session; d , at least once or twice a week. BMI, body mass index; CRC, colorectal cancer; n, number of valid responses. *, p < 0.05 Table 3 Association between each risk factor and CRC, within tumour-location groups Right-sided (n = 94) Left-sided (n = 120) Variable Odds Ratio (95% CI) a Odds Ratio (95% CI) a p -value (left vs right) Males 0.71 (0.45–1.10) 1.25 (0.91–1.72) 0.04 Age 1.02 (1.004–1.04)* 0.98 (0.97–0.99)* < 0.01 BMI ≥ 30 kg/m 2 1.32 (0.78–2.24) 1.57 (1.09–2.27)* 0.59 Immediate family CRC 1.29 (0.72–2.31) 1.57 (1.02–2.41)* 0.60 Sugary drinks (weekly or more) 2.38 (1.48–3.82)* 1.54 (1.08–2.20)* 0.15 Fast food (weekly or more) 1.99 (1.19–3.32)* 1.42 (0.99–2.05) 0.30 Red meat (weekly or more) 1.14 (0.63–2.07) 1.20 (0.77–1.85) 0.90 Processed meat (weekly or more) 0.91 (0.58–1.42) 1.13 (0.82–1.57) 0.43 Physical inactivity b 1.37 (0.83–2.25) 1.56 (1.09–2.23)* 0.68 Current medium to high frequency c and heavy alcohol consumption d 0.97 (0.33–2.86) 2.46 (1.46–4.16)* 0.13 Current or former (≥ 30 pack years) smoker 1.10 (0.55–2.19) 1.49 (0.92–2.42) 0.48 a, , Odds ratios adjusted for sex (except for Males variable); b , less than 2–3 times of 30 minutes moderate intensity exercise/week; c , at least once or twice a week; d , four or more drinks per session. BMI, body mass index; CRC, colorectal cancer; n, number of valid responses *p < 0.05 Table 4 Association between variables and colorectal cancer by age < 50 years ≥ 50 years Variable n cases (%)/n controls (%) Odds Ratio (95% CI) a n cases (%)/n contro (%) Odds Ratio (95% CI) a p (< 50 v ≥ 50) Males 20 (48.8%)/38 (48.1%) 1.03 (0.48–2.19) 140 (53.2%)/284 (51.9%) 1.05 (0.79–1.42) 0.95 BMI ≥ 30 kg/m 2 10 (25.6%)/16 (20.0%) 1.38 (0.55–3.47) 70 (28.5%)/110 (20.9%) 1.51 (1.06–2.13)* 0.83 Immediate family CRC 6 (14.6%)/7 (8.8%) 1.77 (0.55–5.65) 48 (18.3%)/75 (13.7%) 1.41 (0.95–2.10) 0.72 Sugary drinks (weekly or more) 17 (41.5%)/23 (28.7%) 1.74 (0.78–3.88) 81 (30.8%)/108 (19.7%) 1.81 (1.29–2.54)* 0.91 Fast food (weekly or more) 20 (48.8%)/32 (40.0%) 1.41 (0.65–3.06) 71 (27.0%)/99 (18.1%) 1.67 (1.18–2.38)* 0.68 Red meat (weekly or more) 35 (85.4%)/59 (73.8%) 2.11 (0.78–5.74) 222 (84.4%)/458 (83.7%) 1.04 (0.70–1.57) 0.20 Processed meat (weekly or more) 30 (73.2%)/41 (51.2%) 2.70 (1.18–6.19)* 136 (51.7%)/290 (53.0%) 0.94 (0.69–1.27) 0.02* Physical inactivity b 9 (22.0%)/23 (28.7%) 0.68 (0.28–1.66) 78 (29.7%)/109 (19.9%) 1.70 (1.21–2.38)* 0.06 Current medium to high frequency c and heavy alcohol consumption d 6 (15.0%)/5 (6.3%) 2.57 (0.73–9.03) 29 (11.6%)/32 (6.1%) 2.06 (1.20–3.54)* 0.75 Current or former (≥ 30 pack years) smoker 4 (10.5%)/2 (2.6%) 4.32 (0.75–24.83) 35 (14.2%)/63 (12.2%) 1.20 (0.77–1.86) 0.16 a, , Odds ratios adjusted for sex (except for Males variable); b , less than 2–3 times of 30 minutes moderate intensity exercise/week; c , at least once or twice a week; d , four or more drinks per session BMI, body mass index; CRC, colorectal cancer; n, number of valid responses; *p < 0.05 Additional Declarations No competing interests reported. Supplementary Files Figure1JUly301.png Flow diagram of subject enrolment Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 27 Nov, 2025 Reviews received at journal 13 Nov, 2025 Reviews received at journal 12 Nov, 2025 Reviewers agreed at journal 04 Nov, 2025 Reviewers agreed at journal 03 Nov, 2025 Reviewers agreed at journal 02 Nov, 2025 Reviewers agreed at journal 28 Oct, 2025 Reviewers invited by journal 27 Oct, 2025 Editor assigned by journal 23 Oct, 2025 Editor invited by journal 29 Sep, 2025 Submission checks completed at journal 27 Sep, 2025 First submitted to journal 27 Sep, 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. 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09:58:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":991291,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7707153/v1/59cb06d6-0d71-425b-b331-190b7b5a61e1.pdf"},{"id":95210995,"identity":"e649734b-d83f-479f-b36b-c582d92f8102","added_by":"auto","created_at":"2025-11-05 14:11:35","extension":"png","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":35591,"visible":true,"origin":"","legend":"\u003cp\u003eFlow diagram of subject enrolment\u003c/p\u003e","description":"","filename":"Figure1JUly301.png","url":"https://assets-eu.researchsquare.com/files/rs-7707153/v1/10895d221de3a58cdbcfac6b.png"}],"financialInterests":"No competing interests reported.","formattedTitle":"Risk Factors for Early-Onset Colorectal Cancer: The Role of Diet, Lifestyle and Obesity","fulltext":[{"header":"Background","content":"\u003cp\u003eColorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide, with 1.9\u0026nbsp;million new cases reported in 2020. It is also the second leading cause of cancer-related mortality. The incidence of CRC increases with age and the majority of CRC cases are sporadic. Migration studies have shown that individuals relocating from low- to high-risk regions before the age of 30 tend to adopt the CRC risk profile of the host country (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). Notably, a marked increase in CRC incidence and mortality has been observed within a single generation in many low- and middle-income countries (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). Furthermore, the incidence of CRC among individuals under 50 years of age is rising globally (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIn the United States, colorectal cancer is the leading cause of cancer death in men under 50, and the second most common cause of cancer death in women under 50. A similar trend is evident in New Zealand, where the incidence of early-onset colorectal cancer is increasing by an average of 26% per decade. Among the Māori population, the rate of increase is even higher, reported at approximately 36% per decade (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). EOCRC differs from late-onset CRC as it predominantly involves left-sided lesions, particularly in the rectum, rectosigmoid junction, and sigmoid colon (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). While the underlying causes of these epidemiological shifts remain unclear (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e), the presence of birth cohort effects suggests evolving exposure to environmental risk factors over time (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). The specific drivers of carcinogenesis, especially among younger New Zealanders, have yet to be fully elucidated (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eA number of loosely associated lifestyle factors such as diet-associated obesity, sedentary lifestyles, tobacco use, alcohol consumption and the westernisation of diets are increasingly common as well as shared across generations of individuals worldwide (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). These extrinsic influences may contribute to carcinogenesis by inducing aberrant DNA hypermethylation, which can promote deleterious genetic mutations that drive progression through the adenoma–carcinoma sequence (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e). Such changes may occur regardless of age, suggesting that shifting lifestyle behaviours likely play a substantial role in the rising incidence of early-onset CRC.\u003c/p\u003e\u003cp\u003eThe primary objective of this study was to evaluate dietary and lifestyle risk factors in patients recently diagnosed with CRC, compared with age-matched healthy controls. A secondary aim was to explore associations between these risk factors, tumour location, and patient age\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003eStudy design\u003c/strong\u003e. This retrospective, case-control study compared putative risk factors between CRC patients and healthy controls within defined age groups. The sample size was pragmatically determined. Approximately 300 people in the Canterbury region of New Zealand receive a CRC diagnosis annually; this study sought to recruit as many of these patients as possible within this timeframe. This sample was anticipated to provide sufficient power for univariate and multivariate logistic regression analyses to identify independent CRC risk factors. Two community-based healthy controls were selected for each patient, matched by age range and sex.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy population\u003c/strong\u003e. All patients over 18 years of age presenting at Christchurch Hospital with a new diagnosis of colorectal adenocarcinoma were verbally invited to participate in the study. Controls were randomly selected from the electoral role within the same catchment area, matched for age and sex, and supplemented by community recruitment using the same criteria.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate.\u003c/strong\u003e The University of Otago Human Ethics Committee approved the study (H20/043) and informed consent was obtained from all participants who completed the questionnaire (online or in print), which is in line with the Declaration of Helsink\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eBaseline characteristics of participants by case and control status.\u0026nbsp;\u003c/strong\u003eParticipants reported their age, sex, weight and height. Familial CRC risk was assessed by querying immediate family history (parent or sibling diagnosed with CRC). Pathology reports of CRC patients were reviewed to determine tumour anatomical location.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAssessment of lifestyle factors.\u0026nbsp;\u003c/strong\u003eParticipants were surveyed regarding the frequency of consumption of sugary drinks, fast food, red and processed meat. Consumption at least weekly was used as a cut-off for risk assessment. Regular physical activity was defined as at least 2-3 times of 30 minutes of moderate intensity exercise weekly. Smoking history included age at initiation, the number of cigarettes smoked daily and cessation age if applicable. Participants were classified as smokers if currently smoking or former smokers with ≥ 30 pack years; other were considered non-smokers (13). Alcohol consumption was categorised by frequency (low: \u0026lt;1-2 times/week; medium: 1-2 times/week; high: 3-4 times/week) (15) and volume (light: 1 drink/day [12.5 g/day ethanol]; moderate: 2-3 drinks/day [12.6–49.9 g]; heavy: ≥4 drinks/day [≥50 g/day of ethanol] (16).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical analysis.\u003c/strong\u003e Logistic regression models (SPSS version 29.0.2.0) compared cases and controls in terms of the putative risk factors, expressed as odds ratios (OR) with 95% confidence intervals. Analyses controlled for age and sex unless these were variables of interest. Interaction terms tested whether risk factors differentially affected tumour location (left- vs. right-sided) or age (\u0026lt;50 v ≥50years).\u0026nbsp;\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eOf 336 patients with a preliminary diagnosis of CRC invited to take part in the study, 304 completed the questionnaire. The control group comprised 627 participants (26.2% participation rate). Three patients lacking confirmed adenocarcinoma and six controls with a CRC history were excluded\u0026nbsp;(Figure 1). Median ages were 69 (range 29-91) for cases and 72 (range 28-91) for controls (p=0.138); 52% were male (p=0.818, Table 1). There were 41 cases and 80 controls aged \u0026lt; 50 years, and 263 cases and 547 controls aged 50 years and over (Table 3). No significant sex distribution differences were noted between cases and controls in either age cohort, and while controls in the older group were marginally older, this difference was not significant.\u003c/p\u003e\n\u003cp\u003eMedian BMI was 26.3 kg/m\u003csup\u003e2\u003c/sup\u003e (cases range 12.9-44.6; controls 14.8-45.6). Using a BMI ≥30 kg/m\u003csup\u003e2\u003c/sup\u003eas the cut-off for obesity, more CRC patients were obese compared to controls (p=0.020, Table 1). Cases were also more like to report immediate family history of CRC (p=0.04, Table 1).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSeveral lifestyle factors were associated with increased CRC risk (Table 2). Cases reported high regular consumption of sugary drinks and fast food compared to matched controls (OR 1.78, p\u0026lt;0.001 and OR 1.57, p=0.007, respectively). Medium to high frequency and heavy alcohol consumption were more frequent among cases (OR 2.06, p=0.004), whereas controls engaged more in regular physical activity (OR 1.51, p=0.011).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eGiven the predominance of left-sided tumours (69.1%) (Table 1), tumour location associations were examined (Table 3). Right sided cancers were more common in women; left-sided in men (p=0.04). Younger patients more frequently presented with left-sided disease (p\u0026lt;0.01). Obesity was a significant risk factor for left-sided cancer (OR 1.57, p=0.015); right-sided cases were heavier than controls, but not significantly (OR 1.32). Family history of CRC was associated with left-sided but not right-sided cancers (OR 1.57, p=0.042).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eRegular sugary drink and fast food consumption increased CRC risk regardless of tumour location. However, no association was found between meat consumption (red or processed) or smoking and tumour site (Table 3). Physical inactivity increased risk of left-sided disease (OR 1.56, p=0.016). Alcohol-related risk was higher for distal and rectal cancers (OR 2.46, p\u0026lt;0.001) compared to the proximal colon (OR 0.97), even with reduced drinking frequency.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWhen stratified by age, obesity was a significant risk factor among older cases (≥50 years) (OR 1.51, p=0.021). BMI was also notably higher in the younger (˂50 years) cases (OR 1.38) but not a significant risk factor when compared to the control group (Table 4). Sugary drink (OR 1.81, p\u0026lt;0.001) and fast food (OR 1.67, p=0.004) consumption were higher among older patients than controls. Younger patients also consumed these more frequently (OR 1.74 and 1.41, respectively, but differences were non-significant. Processed meat intake was associated with early-onset CRC (OR 2.7, p=0.019) that differed significantly by age group (p=0.02). Older patients exercised less than matched controls (OR 1.70, p=0.002). Heavy alcohol consumption was significantly associated with CRC among older patients (OR 2.06, p=0.009). While smoking status was not significantly associated with CRC overall (p=0.19; Table 2), younger cases were more likely to identify as former or current smokers (OR 4.32) though numbers were very small. Vaping and use of other tobacco products were uncommon (seven cases and six controls).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study identifies the consumption of sugary drinks and fast food, physical inactivity, heavy alcohol intake, and obesity as significant extrinsic risk factors for CRC in New Zealand. The elevated obesity rates observed align with recent reports of increased adiposity-related cancers in the country (17). Lifetime overweight or obesity is increasingly recognised as a major contributor to CRC risk (18). The high prevalence of obesity among New Zealand children and adolescents (19) may be contributing to the rising incidence of CRC, particularly early-onset disease (20). It remains unclear whether obesity itself or the behaviours leading to obesity, such as dietary patterns and sedentary lifestyles, have the greater impact on carcinogenesis. The familial clustering of CRC observed in this study may reflect shared lifestyle exposures across generations in addition to inherited genetic susceptibility.\u003c/p\u003e\n\u003cp\u003eHigh sugar intake has been shown to increase CRC risk through its effects on blood glucose and insulin levels (21-23). Mechanistically, excessive sugar that surpasses the absorptive capacity of the small intestine undergoes fermentation in the colon, potentially compromising mucosal barrier function, particularly in the proximal colon (24, 25). In contrast, the consumption of high-fat fast food promotes the expansion of bile-tolerant, sulphate-reducing bacteria, which produce genotoxic hydrogen sulphide in the colon (26-28). Alcohol-related CRC risk appears to be dose-dependent and may be mediated through alterations in the gut microbiome, resulting in the production of alcohol-derived carcinogenic metabolites (16, 29-31). Physical inactivity may increase CRC risk by prolonging colonic transit time and altering microbiota metabolism toward protein catabolism, leading to an accumulation of genotoxic metabolites (32, 33).\u003c/p\u003e\n\u003cp\u003eRisk factors also exhibited subsite-specific associations. Consistent with prior studies (34)[33], physical inactivity, obesity, sugary drink intake, and alcohol consumption were each associated with increased risk of left-sided tumours (35-38). Interestingly, fast food consumption was linked to right-sided disease, which may reflect the high sugar content typical of fast food meals in New Zealand, along with the associated expansion of sulphate-metabolising bacteria that predispose to distal disease (25, 39, 40). Familial CRC history was most strongly associated with left-sided tumours, again suggesting that shared lifestyle factors may influence tumour location.\u003c/p\u003e\n\u003cp\u003eAge-stratified analyses revealed that processed meat consumption was significantly associated with early-onset CRC, consistent with its classification as a Group 1 carcinogen (41). Processed meats may promote carcinogenesis via nitrate exposure and sulphur-metabolising bacteria generating genotoxic compounds (40, 42, 43). Interestingly, obesity, sugary drink and fast food consumption, heavy alcohol use, and physical inactivity were more strongly associated with CRC in older participants, but not in younger ones. This may reflect the smaller sample size of the early-onset disease cohort or may signal an overall upward shift in lifestyle risk behaviours among younger New Zealanders—whose age-matched controls reported similarly high consumption of sugary drinks and fast food (19, 44). The younger cohort also demonstrated heavier and more frequent alcohol intake, indicating another potential risk factor for early-onset disease (45).\u003c/p\u003e\n\u003cp\u003eAlthough smoking is a well-established risk factor for CRC, it demonstrated a non-significant trend toward increased risk in this study. Tobacco carcinogens are known to induce DNA damage, epigenetic alterations, and pro-inflammatory changes that promote colorectal carcinogenesis (46). The absence of statistical significance in our findings may be attributable to limited sample size or variability in smoking intensity, duration, and timing. Additionally, the increasing shift from traditional cigarette smoking to vaping introduces further complexity, as the long-term oncogenic potential of e-cigarette use remains poorly understood. Future studies incorporating objective biomarkers of tobacco exposure, along with molecular profiling of tumours, are needed to better characterise the role of smoking and related behaviours in the aetiology of early-onset CRC.\u003c/p\u003e\n\u003cp\u003eThis study has several limitations. Data on lifestyle and dietary behaviours were self-reported, introducing the possibility of recall bias. Longitudinal measures of obesity and sedentary behaviour (particularly relevant to early-onset and distal CRC) were not available (47-50). Additionally, protective dietary factors such as fibre intake, which is known to influence colonic transit time and reduce CRC risk, were not assessed (51). Despite these limitations, the study’s population-based design and inclusion of well-matched community controls enhance its generalisability.\u003c/p\u003e\n\u003cp\u003eIn summary, these findings suggest that evolving environmental and lifestyle exposures, combined with familial predisposition, contribute to the increasing incidence of early-onset CRC both in New Zealand and globally (6, 52, 53). Targeted prevention strategies, particularly those aimed at reducing sugary drink and fast food consumption, promoting physical activity, managing obesity, and curbing alcohol use, are urgently required, especially among younger populations. Incorporating both family history and modifiable lifestyle factors into CRC risk stratification models may improve early detection and facilitate personalised screening protocols\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study reinforces the critical role of modifiable lifestyle factors including diet, obesity, physical inactivity, and alcohol consumption in shaping colorectal cancer risk, particularly in young people. The significant associations observed with age, obesity, alcohol consumption and a positive family history of CRC with left-sided disease, as well as the observation of an age-related effect with regards processed meat consumption, collectively underscore the likely multifactorial nature of carcinogenesis in younger populations.\u003c/p\u003e\n\u003cp\u003eThese findings support the need for a comprehensive, population-level approach to CRC prevention that combines behavioural interventions with genetic risk assessment. Early identification of high-risk individuals and the implementation of targeted public health strategies promoting healthier lifestyle behaviours are essential to reversing the rising incidence of early-onset CRC.\u003c/p\u003e\n\u003cp\u003eOngoing research is vital to further elucidate the complex interplay between environmental exposures, genetic susceptibility, and tumour biology. Such insights will be key to refining prevention efforts and developing effective, risk-adapted screening strategies.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate.\u0026nbsp;\u003c/strong\u003eThe University of Otago Human Ethics Committee approved the study (H20/043) and informed consent was obtained from all participants who completed the questionnaire (online or in print).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication.\u0026nbsp;\u003c/strong\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials. The datasets generated and/or analysed during the current study are not publicly available due to data sovereignty requirements but are available from the corresponding author on reasonable request\u0026nbsp; explaining how the data will be used\u003c/strong\u003e\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests.\u0026nbsp;\u003c/strong\u003eThe authors declare they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding.\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors contributions.\u0026nbsp;\u003c/strong\u003eJK and FF conceptualised the study. JK, OW, AVJ, JS and AMcC were involved in the recruitment of study participants. CF and AMcM formally analysed the data. JK interpreted the analysis and wrote the original draft of the manuscript that FF reviewed and edited. All authors read and approved the final manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements.\u0026nbsp;\u003c/strong\u003eJK and FF acknowledge the support of Oncology nurses Desma Dawber and Teresa Hall for their help with recruiting the patient cohort.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eFlood DM, Weiss NS, Cook LS, Emerson JC, Schwartz SM, Potter JD. Colorectal cancer incidence in Asian migrants to the United States and their descendants. Cancer causes control: CCC. 2000;11(5):403\u0026ndash;11.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHaggar FA, Boushey RP. Colorectal cancer epidemiology: incidence, mortality, survival, and risk factors. Clin Colon Rectal Surg. 2009;22(4):191\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eArnold M, Sierra MS, Laversanne M, Soerjomataram I, Jemal A, Bray F. 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Risk Factors for Early-Onset Colorectal Cancer: A Systematic Review and Meta-analysis. Clin Gastroenterol Hepatol. 2022;20(6):1229\u0026ndash;e405.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHua H, Jiang Q, Sun P, Xu X. Risk factors for early-onset colorectal cancer: systematic review and meta-analysis. Front Oncol. 2023;13:1132306.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cdiv class=\"SimplePara\"\u003eBaseline characteristics of participants by case and control status\u003c/div\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eCharacteristics\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003eControls (%) Cases\u003csup\u003eb\u003c/sup\u003e (%) Odds ratio (95% CI)\u003csup\u003ea\u003c/sup\u003e p-value\u003c/div\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eMales, n (%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e322/627 (51.4)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e160/304 (52.6)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.03 (0.78\u0026ndash;1.36)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.818\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eMedian age (range)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e72 (28\u0026ndash;91)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e69 (29\u0026ndash;91)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.99 (0.98\u0026ndash;1.002)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.138\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eMedian BMI (range)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e26.3 (12.9\u0026ndash;44.6)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e26.3 (14.8\u0026ndash;45.6)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.02 (0.99\u0026ndash;1.05)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.146\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eBMI\u0026thinsp;\u0026ge;\u0026thinsp;30 (kg/m\u003csup\u003e2\u003c/sup\u003e), n (%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e126/606 (20.8)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e80/285 (28.1)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.47 (1.06\u0026ndash;2.04)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e0.020\u003c/span\u003e\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eImmediate family CRC, n (%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e82/627 (13.1)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e54/304 (17.8)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.49 (1.02\u0026ndash;2.17)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e0.040\u003c/span\u003e\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eTumour location (n)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eRight (proximal colon)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e-\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e94 (30.9%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eLeft (distal colon/rectum)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e-\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e210 (69.1%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003csup\u003ea\u003c/sup\u003e, Odds ratios adjusted for age and sex; \u003csup\u003eb\u003c/sup\u003e, the one person with CRC on both sides allocated to proximal only;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003eBMI, body mass index; CRC, colorectal cancer; n, number of valid responses.\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e*, p\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003cbr/\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cdiv class=\"SimplePara\"\u003eAssociation between lifestyle factors and colorectal cancer by case and control status\u003c/div\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eLifestyle factor\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003eControls\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003en (%)\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003eCases\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003en (%)\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003eOdds ratio (95% CI)\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003ep-value\u003c/div\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eSugary drinks (weekly or more)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e131/627 (20.9%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e98/304 (32.2%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.78 (1.30\u0026ndash;2.43)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/span\u003e\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eFast food (weekly or more)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e131/627 (20.9%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e91/304 (29.9%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.57 (1.13\u0026ndash;2.16)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e0.007\u003c/span\u003e\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eRed meat (weekly or more)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e517/627 (82.5%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e257/304 (84.5%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.18 (0.81\u0026ndash;1.71)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.397\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eProcessed meat (weekly or more)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e331/627 (52.8%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e166/304 (54.6%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.05 (0.80\u0026ndash;1.40)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.714\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003ePhysical inactivity\u003csup\u003ea\u003c/sup\u003e\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e132/627 (21.1%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e84/304 (28.6%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.51 (1.10\u0026ndash;2.07)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e0.011\u003c/span\u003e\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eCurrent high frequency\u003csup\u003eb\u003c/sup\u003e and heavy alcohol consumption\u003csup\u003ec\u003c/sup\u003e\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e12/606 (2.0%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e17/289 (5.9%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e3.05 (1.43\u0026ndash;6.52)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e0.004\u003c/span\u003e\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eCurrent medium to high frequency\u003csup\u003ed\u003c/sup\u003e and heavy alcohol consumption\u003csup\u003ec\u003c/sup\u003e\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e37/606 (6.1%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e35/289 (12.1%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e2.06 (1.25\u0026ndash;3.40)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e0.004\u003c/span\u003e\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eCurrent or former (\u0026ge;\u0026thinsp;30 pack years) smoker\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e65/595 (10.9%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e39/284 (13.7%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.33 (1.43\u0026ndash;6.52)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.193\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003eOdds ratios adjusted for age and sex; \u003csup\u003ea\u003c/sup\u003e, less than 2\u0026ndash;3 times of 30 minutes moderate intensity exercise/week; \u003csup\u003eb\u003c/sup\u003e, three or more times a week; \u003csup\u003ec\u003c/sup\u003e, four or more drinks per session; \u003csup\u003ed\u003c/sup\u003e, at least once or twice a week. BMI, body mass index; CRC, colorectal cancer; n, number of valid responses. *, p\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003cbr/\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cdiv class=\"SimplePara\"\u003eAssociation between each risk factor and CRC, within tumour-location groups\u003c/div\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003eRight-sided (n\u0026thinsp;=\u0026thinsp;94)\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003eLeft-sided (n\u0026thinsp;=\u0026thinsp;120)\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eVariable\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003eOdds Ratio (95% CI)\u003csup\u003ea\u003c/sup\u003e\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003eOdds Ratio (95% CI)\u003csup\u003ea\u003c/sup\u003e\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003ep -value\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e(left vs right)\u003c/div\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eMales\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.71 (0.45\u0026ndash;1.10)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.25 (0.91\u0026ndash;1.72)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e0.04\u003c/span\u003e\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eAge\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.02 (1.004\u0026ndash;1.04)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.98 (0.97\u0026ndash;0.99)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e\u0026lt;\u0026thinsp;0.01\u003c/span\u003e\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eBMI\u0026thinsp;\u0026ge;\u0026thinsp;30 kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.32 (0.78\u0026ndash;2.24)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.57 (1.09\u0026ndash;2.27)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.59\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eImmediate family CRC\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.29 (0.72\u0026ndash;2.31)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.57 (1.02\u0026ndash;2.41)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.60\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eSugary drinks (weekly or more)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e2.38 (1.48\u0026ndash;3.82)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.54 (1.08\u0026ndash;2.20)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.15\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eFast food (weekly or more)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.99 (1.19\u0026ndash;3.32)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.42 (0.99\u0026ndash;2.05)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.30\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eRed meat (weekly or more)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.14 (0.63\u0026ndash;2.07)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.20 (0.77\u0026ndash;1.85)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.90\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eProcessed meat (weekly or more)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.91 (0.58\u0026ndash;1.42)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.13 (0.82\u0026ndash;1.57)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.43\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003ePhysical inactivity\u003csup\u003eb\u003c/sup\u003e\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.37 (0.83\u0026ndash;2.25)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.56 (1.09\u0026ndash;2.23)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.68\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eCurrent medium to high frequency\u003csup\u003ec\u003c/sup\u003e and heavy alcohol consumption\u003csup\u003ed\u003c/sup\u003e\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.97 (0.33\u0026ndash;2.86)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e2.46 (1.46\u0026ndash;4.16)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.13\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eCurrent or former (\u0026ge;\u0026thinsp;30 pack years) smoker\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.10 (0.55\u0026ndash;2.19)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.49 (0.92\u0026ndash;2.42)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.48\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003csup\u003ea,\u003c/sup\u003e, Odds ratios adjusted for sex (except for Males variable);\u003csup\u003eb\u003c/sup\u003e, less than 2\u0026ndash;3 times of 30 minutes moderate intensity exercise/week; \u003csup\u003ec\u003c/sup\u003e, at least once or twice a week; \u003csup\u003ed\u003c/sup\u003e, four or more drinks per session.\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003eBMI, body mass index; CRC, colorectal cancer; n, number of valid responses\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003e*p\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003cbr/\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cdiv class=\"SimplePara\"\u003eAssociation between variables and colorectal cancer by age\u003c/div\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;50 years\u003c/div\u003e \u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e\u0026ge;\u0026thinsp;50 years\u003c/div\u003e \u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eVariable\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003en\u003csub\u003ecases\u003c/sub\u003e(%)/n\u003csub\u003econtrols\u003c/sub\u003e(%)\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003eOdds Ratio (95% CI)\u003csup\u003ea\u003c/sup\u003e\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003en\u003csub\u003ecases\u003c/sub\u003e(%)/n\u003csub\u003econtro\u003c/sub\u003e(%)\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003eOdds Ratio (95% CI)\u003csup\u003ea\u003c/sup\u003e\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003ep\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e(\u0026lt;\u0026thinsp;50 v\u0026thinsp;\u0026ge;\u0026thinsp;50)\u003c/div\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eMales\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e20 (48.8%)/38 (48.1%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.03 (0.48\u0026ndash;2.19)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e140 (53.2%)/284 (51.9%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.05 (0.79\u0026ndash;1.42)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.95\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eBMI\u0026thinsp;\u0026ge;\u0026thinsp;30 kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e10 (25.6%)/16 (20.0%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.38 (0.55\u0026ndash;3.47)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e70 (28.5%)/110 (20.9%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.51 (1.06\u0026ndash;2.13)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.83\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eImmediate family CRC\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e6 (14.6%)/7 (8.8%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.77 (0.55\u0026ndash;5.65)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e48 (18.3%)/75 (13.7%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.41 (0.95\u0026ndash;2.10)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.72\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eSugary drinks (weekly or more)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e17 (41.5%)/23 (28.7%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.74 (0.78\u0026ndash;3.88)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e81 (30.8%)/108 (19.7%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.81 (1.29\u0026ndash;2.54)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.91\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eFast food (weekly or more)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e20 (48.8%)/32 (40.0%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.41 (0.65\u0026ndash;3.06)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e71 (27.0%)/99 (18.1%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.67 (1.18\u0026ndash;2.38)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.68\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eRed meat (weekly or more)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e35 (85.4%)/59 (73.8%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e2.11 (0.78\u0026ndash;5.74)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e222 (84.4%)/458 (83.7%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.04 (0.70\u0026ndash;1.57)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.20\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eProcessed meat (weekly or more)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e30 (73.2%)/41 (51.2%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e2.70 (1.18\u0026ndash;6.19)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e136 (51.7%)/290 (53.0%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.94 (0.69\u0026ndash;1.27)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003e0.02*\u003c/span\u003e\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003ePhysical inactivity\u003csup\u003eb\u003c/sup\u003e\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e9 (22.0%)/23 (28.7%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.68 (0.28\u0026ndash;1.66)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e78 (29.7%)/109 (19.9%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.70 (1.21\u0026ndash;2.38)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.06\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eCurrent medium to high frequency\u003csup\u003ec\u003c/sup\u003e and heavy alcohol consumption\u003csup\u003ed\u003c/sup\u003e\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e6 (15.0%)/5 (6.3%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e2.57 (0.73\u0026ndash;9.03)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e29 (11.6%)/32 (6.1%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e2.06 (1.20\u0026ndash;3.54)*\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.75\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eCurrent or former (\u0026ge;\u0026thinsp;30 pack years) smoker\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e4 (10.5%)/2 (2.6%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e4.32 (0.75\u0026ndash;24.83)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e35 (14.2%)/63 (12.2%)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.20 (0.77\u0026ndash;1.86)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.16\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"6\"\u003e\u003csup\u003ea,\u003c/sup\u003e, Odds ratios adjusted for sex (except for Males variable); \u003csup\u003eb\u003c/sup\u003e, less than 2\u0026ndash;3 times of 30 minutes moderate intensity exercise/week; \u003csup\u003ec\u003c/sup\u003e, at least once or twice a week; \u003csup\u003ed\u003c/sup\u003e, four or more drinks per session\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"6\"\u003eBMI, body mass index; CRC, colorectal cancer; n, number of valid responses; *p\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003cbr/\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-cancer","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bcan","sideBox":"Learn more about [BMC Cancer](http://bmccancer.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bcan/default.aspx","title":"BMC Cancer","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"colorectal cancer, diet, lifestyle, obesity","lastPublishedDoi":"10.21203/rs.3.rs-7707153/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7707153/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground.\u003c/h2\u003e\u003cp\u003eColorectal cancer (CRC) is the third most commonly diagnosed cancer globally, and remains the second leading cause of cancer-related mortality. The incidence of early-onset colorectal cancer (EOCRC) among young adults before the age of 50 is rising worldwide, with EOCRC rates in New Zealand increasing by 26% per decade overall and by 16% in Maori. The underlying causes remain unclear although environmental and lifestyle factors are suspected contributors. The study investigated associations between known risk factors and the development of CRC in a New Zealand population, with a focus on tumour location and age at diagnosis.\u003c/p\u003e\u003ch2\u003eMethods.\u003c/h2\u003e\u003cp\u003eA retrospective case-control study was conducted in Canterbury, New Zealand comparing recently diagnosed CRC patients (n\u0026thinsp;=\u0026thinsp;304) with age- and sex-matched community controls (n\u0026thinsp;=\u0026thinsp;627). Data on diet, obesity, physical activity, smoking, alcohol consumption, and family history were collected via a self-reported questionnaire. Logistic regression was used to assess associations between risk factors, tumour location, and age at diagnosis.\u003c/p\u003e\u003ch2\u003eResults.\u003c/h2\u003e\u003cp\u003eCRC patients had significantly higher rates of obesity (BMI\u0026thinsp;\u0026ge;\u0026thinsp;30 kg/m\u0026sup2;; OR 1.47, p\u0026thinsp;=\u0026thinsp;0.020), positive family history (OR 1.49, p\u0026thinsp;=\u0026thinsp;0.040), sugary drink (OR 1.78, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and fast food consumption (OR 1.57, p\u0026thinsp;=\u0026thinsp;0.007), heavy alcohol intake (OR 3.05, p\u0026thinsp;=\u0026thinsp;0.004), and lower levels of physical activity (OR 1.51, p\u0026thinsp;=\u0026thinsp;0.011) compared with controls. Left-sided tumours (69.1% of cases) were significantly associated with obesity (OR 1.57, p\u0026thinsp;=\u0026thinsp;0.015), family history (OR 1.57, p\u0026thinsp;=\u0026thinsp;0.042), physical inactivity (OR 1.56, p\u0026thinsp;=\u0026thinsp;0.016), and alcohol use (OR 2.46, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Processed meat consumption was significantly associated with EOCRC (OR 2.70, p\u0026thinsp;=\u0026thinsp;0.019).\u003c/p\u003e\u003ch2\u003eConclusions.\u003c/h2\u003e\u003cp\u003eModifiable factors, particularly sugary drink and fast food intake, obesity, alcohol use, and physical inactivity significantly associate with CRC risk in New Zealand, particularly for left-sided and early-onset disease. Familial predisposition further compounds this risk. These findings highlight the need for targeted prevention strategies that combine lifestyle modification with genetic risk assessment\u003c/p\u003e","manuscriptTitle":"Risk Factors for Early-Onset Colorectal Cancer: The Role of Diet, Lifestyle and Obesity","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-05 14:11:31","doi":"10.21203/rs.3.rs-7707153/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-11-27T10:27:32+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-13T13:32:14+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-13T03:51:31+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"37278006969533378131035891234515433964","date":"2025-11-05T04:19:33+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"126857137115397407050842850896421088884","date":"2025-11-03T08:17:42+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"87512105667186415645720657996798069254","date":"2025-11-03T04:15:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"180641608120675237740729140701852995338","date":"2025-10-28T08:51:36+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-27T06:49:55+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-23T08:02:04+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-09-29T06:45:00+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-09-27T17:00:28+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Cancer","date":"2025-09-27T08:22:56+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-cancer","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bcan","sideBox":"Learn more about [BMC Cancer](http://bmccancer.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bcan/default.aspx","title":"BMC Cancer","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"656c8d14-af7e-47ce-8de3-12daf0411319","owner":[],"postedDate":"November 5th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2026-05-19T07:24:36+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-05 14:11:31","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7707153","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7707153","identity":"rs-7707153","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}