The Association Between Religiosity, Spirituality and Colorectal Cancer Screening: A Longitudinal Analysis of Alberta's Tomorrow Project in Canada.

We explored longitudinal associations between religion/spirituality (R/S) Salience and R/S Attendance, and colorectal cancer screening, among adults aged ≥ 50 years in Alberta, Canada. R/S Salience was not statistically significantly associated with colorectal cancer screening (adjusted odds ratio [aOR]: 1.06, 95% confidence interval [CI] 0.88-1.28). Conversely, R/S Attendance was statistically significantly associated with higher odds of colorectal cancer screening: the aOR was 1.28 (95% CI 1.02-1.59) for participants attending services at least once a month and 1.31 (95% CI 1.01-1.69) for participants attending between one and four times yearly, compared to participants who never attended. Researchers should explore the possibility of delivering colorectal cancer screening programs in R/S settings.

Using classification and regression trees to model missingness in youth BMI, height and body mass data. / Utilisation des arbres de classification et de régression pour modéliser les données manquantes sur l'IMC, la taille et la masse corporelle chez les jeunes.

INTRODUCTION: Research suggests that there is often a high degree of missingness in youth body mass index (BMI) data derived from self-reported measures, which may have a large effect on research findings. The first step in handling missing data is to examine the levels and patterns of missingness. However, previous studies examining youth BMI missingness used logistic regression, which is limited in its ability to discern subgroups or identify a hierarchy of importance for variables, aspects that may go a long way in helping understand missing data patterns. METHODS: This study used sex-stratified classification and regression tree (CART) models to examine missingness in height, body mass and BMI data among 74 501 youth participating in the 2018/19 COMPASS study (a prospective cohort study examining health behaviours among Canadian youth), where 31% of BMI data were missing. Diet, movement, academic, mental health and substance use variables were examined for associations with missingness in height, body mass and BMI. RESULTS: CART models indicated that the combination of being younger, having a selfperception of being overweight, being less physically active and having poorer mental health yielded female and male subgroups highly likely to be missing BMI values. Survey respondents who did not perceive themselves as overweight and who were older were unlikely to be missing BMI values. CONCLUSION: The subgroups identified by the CART models indicate that a sample that deletes cases with missing BMI would be biased towards physically, emotionally and mentally healthier youth. Given the ability of CART models to identify these subgroups and a hierarchy of variable importance, they are an invaluable tool for examining missing data patterns and appropriate handling of missing data.

Exploring the association between religious participation and memory in middle- and older-aged adults in the Canadian Longitudinal Study on Aging.

To investigate the association between religious participation and memory in persons aged 45-85 years. Using the Canadian Longitudinal Study on Aging, frequency of religious participation was measured from "daily" to "never"; immediate and delayed recall memory were assessed with the Rey Auditory Verbal Learning Test. We regressed memory onto religious participation for persons aged < 65 years and persons aged ≥ 65 years. We found some evidence of effect modification: among persons < 65 years, monthly to yearly participation versus never attending was positively associated with immediate and delayed recall memory; among persons aged ≥ 65 years, weekly or more participation versus never attending was negatively associated with immediate and delayed recall memory. However, regression coefficients were small (-0.09 ≤ B ≤ 0.06) and most were not statistically significant (p < 0.05). Insufficient evidence existed to conclude that religious participation was associated with memory in our sample.

The impact of assistive devices on community-dwelling older adults and their informal caregivers: a systematic review.

OBJECTIVE: The purpose of this systematic review is to assess the impact of assistive devices on the life satisfaction of (Research Question 1), and informal caregiving hours received by (Research Question 2), community-dwelling older adults (≥ 65 years). METHODS: We searched CINAHL, MEDLINE, and Scopus from database inception to March 2022. For each question, two reviewers independently screened citations, extracted and narratively synthesized the data, and assessed article quality and strength of evidence. RESULTS: Of the 1391 citations screened, we found two articles pertaining to each question, for a total of four articles. In general, assistive device use was not associated with life satisfaction, while it was positively associated with informal caregiving hours. However, the risk of bias was serious across the two studies for Research Question 1, and the overall quality of evidence was "very low". The risk of bias was not serious across the two studies included in Research Question 2 and the overall quality of evidence was "low". CONCLUSION: Due to the scarcity of studies, the limitations of existing studies (i.e., risk of bias), and the evidence being low or very low quality, we could not draw firm conclusions about the associations of interest. Additional research will produce a better understanding of the two relationships and provide further evidence to inform policy decisions regarding the provision and funding of assistive devices for community-dwelling older adults. TRIAL REGISTRATION: This systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database of systematic reviews (identification number: CRD42021248929 ).

Learning from missing data: examining nonreporting patterns of height, weight, and BMI among Canadian youth.

BACKGROUND: Youth body mass index (BMI), derived from self-reported height and weight, is commonly prone to nonreporting. A considerable proportion of overweight and obesity (OWOB) research relies on such self-report data, however little literature to date has examined this nonreporting and the potential impact on research conclusions. The objective of this study was to examine the characteristics and predictors of missing data in youth BMI, height, and weight. METHODS: Using a sample of 74,501 Canadian secondary school students who participated in the COMPASS study in 2018/19, sex-stratified generalized linear mixed models were run to examine predictors of missing data while controlling for school-level clustering. RESULTS: In this sample, 31% of BMI data were missing. A variety of diet, exercise, mental health, and substance use variables were associated with BMI, height, and weight missingness. Perceptions of being overweight (females: 95% CI (1.42,1.62), males: 95% CI (1.71,2.00)) as well as intentions to lose weight (females: 95% CI (1.17,1.33), males: 95% CI (1.13,1.32)) were positively associated with BMI missingness. CONCLUSIONS: Findings from this study suggest that nonreporting in youth height and weight is likely somewhat related to the values themselves, and hint that social desirability may play a substantial role in nonreporting. The predictors of missingness identified in this study can be used to inform future studies on the potential bias stemming from missing data and identify auxiliary variables that may be used for multiple imputation approaches.

Biological Embedding of Psychosocial Stressors Within a Sample of Canadian Firefighters: An Exploratory Analysis.

OBJECTIVE: We wanted to determine whether the biological embedding of perceived psychosocial stress could be observed within a sample of Canadian firefighters. METHODS: We collected sociodemographic and general health-related information from 58 firefighters. In addition, measures of work-related and general life psychosocial stress, perceived social support, and physiological parameters thought to reflect the embedding of stress were gathered and analyzed using analysis of variance and linear regression models. RESULTS: Despite observing a positive relationship between psychosocial stress and allostatic load, the association was not significant; however, age did significantly predict allostatic load ( B = 0.09, P = 0.04). Notably, our participants reported abundant social support that was inversely associated with perceived stress. CONCLUSIONS: Although perceived stress did not significantly affect allostatic load in our sample, high levels of social support may have provided an important countervailing force.

The association between religiosity, spirituality, and breast cancer screening: A cross-sectional analysis of Alberta's Tomorrow Project.

Breast cancer is the leading cause of cancer-related mortality among women. Screening permits the early detection and treatment of malignancies, thereby reducing mortality. A woman's religiosity and spirituality (R/S) may facilitate screening through encouragement of healthy behaviors. Population-level data from Alberta's Tomorrow Project (ATP) were used to explore the cross-sectional association between R/S and breast cancer screening among women aged 50 to 69 years who did not have a history of breast cancer. Two variables were used to measure R/S: (1) R/S Salience was defined as the importance of religion and spirituality in one's life; (2) R/S Attendance was defined as the frequency of attendance at religious or spiritual services. We regressed breast cancer screening (mammogram: yes/no) on each R/S variable in separate multivariable logistic regression models. At baseline (n = 2569), 94% of women reported receiving a mammogram. Greater R/S Salience was not associated with receipt of mammogram: the adjusted odds ratio (aOR) was 1.04 (95% confidence interval [CI]: 0.71-1.51. R/S Attendance also showed no association with mammogram: attending at least once monthly versus never attending (aOR: 1.10; 95% CI: 0.71-1.69); attending one to four times yearly versus never attending (aOR: 0.95, 95% CI: 0.57-1.58). Further research could examine specific subgroups of the population, e.g., whether use of R/S to promote breast cancer screening may be more effective among females with strong pre-existing connections to faith.

Examining if changes in gender-specific and co-ed intramural programs affect youth physical activity over time: a natural experiment evaluation using school- and student-level data from the COMPASS study.

BACKGROUND: Despite the benefits of physical activity (PA), the majority of Canadian youth are falling short of the recommended 60 min of moderate-to-vigorous physical activity (MVPA) per day. School-based physical activity programs such as intramurals, are important opportunities for youth to be physically active. There is limited evidence available on the impact of gender-specific (e.g., female-only, male-only) and co-ed intramurals on youth PA over time, however, evidence suggests female-only intramurals may be important for female MVPA. This research aims to capitalize on a natural experiment to generate practice-based evidence on the impact of changes in gender-specific and co-ed intramurals on youth MVPA over time. METHODS: This study used linked longitudinal school- and student-level data from Ontario secondary schools in year 5 (Y5:2016-2017), year 6 (Y6: 2017-2018) and year 7 (Y7: 2018-2019) of the COMPASS study. Data on intramurals from 55 schools were used to determine the changes to gender-specific and co-ed intramurals that occurred from Y5 to Y6. Baseline demographic characteristics were measured and data on PA and sport participation were collected in Y5, Y6 and Y7 on a sample of 4417 students. Hierarchical linear mixed regression models were used to estimate how changes in gender-specific and co-ed intramurals were associated with youth MVPA over time. RESULTS: Participation in intramural, varsity and community sport were all positively and significantly associated with youth MVPA. Changes in gender-specific and co-ed intramurals were not significantly associated with youth MVPA in Y6 or Y7. However, the positive association between maintaining the addition of gender-specific intramurals on female MVPA in Y7 was on par with the significance level of α = 0.05, suggesting that adding gender-specific intramurals may be important for female MVPA. CONCLUSIONS: Adding gender-specific and co-ed intramurals may not be sufficient strategies to increase PA among youth. Further research should explore the effect of gender-specific intramurals on youth PA, as this study may have been underpowered at the school-level. Gender-specific intramurals may promote a supportive PA environment that promotes MVPA, especially among females. These intramurals may be an important component of more comprehensive strategies to increase youth MVPA.

Latent classes associated with the intention to use a symptom checker for self-triage.

It is currently unknown which attitude-based profiles are associated with symptom checker use for self-triage. We sought to identify, among university students, attitude-based latent classes (population profiles) and the association between latent classes with the future use of symptom checkers for self-triage. Informed by the Technology Acceptance Model and a larger mixed methods study, a cross-sectional survey was developed and administered to students (aged between 18 and 34 years of age) at a University in Ontario. Latent class analysis (LCA) was used to identify attitude-based profiles that exist among the sample while general linear modeling was applied to identify the association between latent classes and future symptom checker use for self-triage. Of the 1,547 students who opened the survey link, 1,365 did not use a symptom checker in the past year and were thus identified as "non-users". After removing missing data (remaining sample = n = 1,305), LCA revealed five attitude-based profiles: tech acceptors, tech rejectors, skeptics, tech seekers, and unsure acceptors. Tech acceptors and tech rejectors were the most and least prevalent classes, respectively. As compared to tech rejectors, tech seekers and unsure acceptors were the latent classes with the highest and lowest odds of future symptom checker use, respectively. After controlling for confounders, the effect of latent classes on symptom checker use remains significant (p-value < .0001) with the odds of future use in tech acceptors being 5.6 times higher than the odds of future symptom checker use in tech rejectors [CI: (3.458, 9.078); p-value < .0001]. Attitudes towards AI and symptom checker functionality result in different population profiles that have different odds of using symptom checkers for self-triage. Identifying a person's or group's membership to a population profile could help in developing and delivering tailored interventions aimed at maximizing use of validated symptom checkers.

Use of symptom checkers for COVID-19-related symptoms among university students: a qualitative study.

OBJECTIVE: Symptom checkers are potentially beneficial tools during pandemics. To increase the use of the platform, perspectives of end users must be gathered. Our objectives were to understand the perspectives and experiences of young adults related to the use of symptom checkers for assessing COVID-19-related symptoms and to identify areas for improvement. METHODS: We conducted semistructured qualitative interviews with 22 young adults (18-34 years of age) at a university in Ontario, Canada. Interviews were audio-recorded, transcribed, and analysed using inductive thematic analysis. RESULTS: We identified six main themes related to the decision of using a symptom checker for COVID-19 symptoms: (1) presence of symptoms or a combination of symptoms, (2) knowledge about COVID-19 symptoms, (3) fear of seeking in-person healthcare services, (4) awareness about symptom checkers, (5) paranoia and (6) curiosity. Participants who used symptom checkers shared by governmental entities reported an overall positive experience. Individuals who used non-credible sources reported suboptimal experiences due to lack of perceived credibility. Five main areas for improvement were identified: (1) information about the creators of the platform, (2) explanation of symptoms, (3) personalised experience, (4) language options, and (5) option to get tested. CONCLUSIONS: This study suggests an increased acceptance of symptom checkers due to the perceived risks of infection associated with seeking in-person healthcare services. Symptom checkers have the potential to reduce the burden on healthcare systems and health professionals, especially during pandemics; however, these platforms could be improved to increase use.

A quasi-experimental examination of how changes in school-level intramurals are associated with physical activity among a sample of Canadian secondary school students from the COMPASS study.

INTRODUCTION: Intramurals in schools may encourage physical activity among youth. Schools are continuously making changes to these intramurals, yet it is not well understood how these changes impact youth physical activity. The main objective of this research was to examine if changes in the number of intramurals were associated with youth physical activity over time with a secondary objective to explore the association between sport participation and physical activity among youth over time. METHODS: This study used three years of linked longitudinal school- and student-level data from Ontario schools in year 5 (Y5: 2016-2017), year 6 (Y6: 2017-2018) and year 7 (Y7: 2018-2019) of the COMPASS study. Data on intramurals from 55 schools were collected from the School Programs and Policies questionnaire to determine intramural changes that were made from Y5 to Y6. Using the COMPASS Student Questionnaire, baseline demographics were collected and data on physical activity and sport participation were measured at Y5, Y6 and Y7 on 4417 students. Hierarchical linear mixed regression models were used to estimate how changes in intramurals were associated with youth physical activity over time. RESULTS: Changes in school-specific intramurals were not significantly associated with physical activity over time. Intramural, varsity and community sport participation were all positively and significantly associated with youth physical activity among female and males. CONCLUSIONS: Intramural, varsity and community sport participation are important opportunities for youth physical activity. Schools should offer a variety of intramural and varsity sports to encourage physical activity. Although adding intramurals may not be effective at increasing youth physical activity, they may be effective when used in combination with other strategies to increase physical activity.

Examining If Changes in the Type of School-Based Intramural Programs Affect Youth Physical Activity over Time: A Natural Experiment Evaluation.

(1) School-based physical activity programs such as intramurals provide youth with inclusive opportunities to be physically active, yet we know little about how types of intramurals (e.g., team and individual sports) may contribute to youth MVPA. This research aims to evaluate how real-world changes in types of intramurals available in schools impact youth physical activity over time. (2) This study used three years of longitudinal school- and student-level data from Ontario schools participating in year 5 (2016-2017), year 6 (2017-2018) and year 7 (2018-2019) of the COMPASS study. Data on types of intramural programs from 55 schools were obtained, baseline demographic characteristics were measured and data on physical activity and sport participation were collected on a sample of 4417 students. Hierarchical linear mixed regression models were used to estimate how changes in the type of intramurals associate with youth MVPA over time. (3) Regardless of participation, adding individual and team intramurals was significantly and positively associated with female MVPA in Y6. (4) The indirect, but positive relationship between adding individual and team intramurals and female MVPA may be explained by other characteristics of the school environment that are conducive to female MVPA.

Young Adults' Perspectives on the Use of Symptom Checkers for Self-Triage and Self-Diagnosis: Qualitative Study.

BACKGROUND: Young adults often browse the internet for self-triage and diagnosis. More sophisticated digital platforms such as symptom checkers have recently become pervasive; however, little is known about their use. OBJECTIVE: The aim of this study was to understand young adults' (18-34 years old) perspectives on the use of the Google search engine versus a symptom checker, as well as to identify the barriers and enablers for using a symptom checker for self-triage and self-diagnosis. METHODS: A qualitative descriptive case study research design was used. Semistructured interviews were conducted with 24 young adults enrolled in a university in Ontario, Canada. All participants were given a clinical vignette and were asked to use a symptom checker (WebMD Symptom Checker or Babylon Health) while thinking out loud, and were asked questions regarding their experience. Interviews were audio-recorded, transcribed, and imported into the NVivo software program. Inductive thematic analysis was conducted independently by two researchers. RESULTS: Using the Google search engine was perceived to be faster and more customizable (ie, ability to enter symptoms freely in the search engine) than a symptom checker; however, a symptom checker was perceived to be useful for a more personalized assessment. After having used a symptom checker, most of the participants believed that the platform needed improvement in the areas of accuracy, security and privacy, and medical jargon used. Given these limitations, most participants believed that symptom checkers could be more useful for self-triage than for self-diagnosis. Interestingly, more than half of the participants were not aware of symptom checkers prior to this study and most believed that this lack of awareness about the existence of symptom checkers hindered their use. CONCLUSIONS: Awareness related to the existence of symptom checkers and their integration into the health care system are required to maximize benefits related to these platforms. Addressing the barriers identified in this study is likely to increase the acceptance and use of symptom checkers by young adults.

Perceived susceptibility to developing cancer and screening for colorectal and prostate cancer: A longitudinal analysis of Alberta's Tomorrow Project.

INTRODUCTION: To assess the association between perceived susceptibility of developing cancer and being screened via sigmoidoscopy/colonoscopy and prostate-specific antigen, respectively. METHODS: Participants aged 35-69, who resided in Alberta, Canada, were enrolled into the study between 2000 and 2008. We used general linear mixed models, adjusted for age, marital status, work status, education, family history and place of residence, to explore the association. RESULTS: Perceived susceptibility of developing cancer was associated with both screening tests at baseline and a maximum of 14-year follow-up: (i) colorectal cancer screening - adjusted odds ratios were 1.97 (95% CI = 1.52-2.55) per one-unit increase in participants' personal belief in susceptibility to cancer, and 1.03 (95% CI = 1.00-1.04) per one-percent increase in participants' estimate of their own chance of developing cancer; (ii) prostate cancer screening - adjusted odds ratios were 1.36 times greater (95% CI = 1.07-1.72), and 1.02 times higher (95% CI = 1.01-1.03), for each respective perceived susceptibility measure. CONCLUSION: Health promotion can focus on targeting and heightening personal perceived susceptibility of developing cancer in jurisdictions with low screening rates for colorectal or prostate cancer.

Determining the long-term health burden and risk of sequelae for 14 foodborne infections in British Columbia, Canada: protocol for a retrospective population-based cohort study.

INTRODUCTION: Over one in eight Canadians is affected by a foodborne infection annually; however, the long-term consequences, including the risks and costs of sequelae, are unclear. We aim to estimate the health burden and direct costs of 14 infections commonly transmitted by food, considering the acute illness and subsequent sequelae and mortality, for the population of British Columbia, Canada (~4.7 million). METHODS AND ANALYSIS: We will conduct a population-based retrospective cohort study of the British Columbia provincial population, over a 10-year study period (1 January 2005 to 31 December 2014). Exposure is defined as a provincially reported illness caused by Clostridium botulinum, Campylobacter, Cryptosporidium, Cyclospora, Giardia, hepatitis A virus, Listeria, non-typhoidal Salmonella spp, Salmonella Typhi, Salmonella Paratyphi, Shiga toxin-producing Escherichia coli, Shigella, Vibrio parahaemolyticus or Yersinia (excluding pestis). We will link individual-level longitudinal data from eight province-wide administrative health and reportable disease databases that include physician visits, hospitalisations and day surgeries, deaths, stillbirths, prescription medications (except those to treat HIV) and reportable foodborne diseases. Using these linked databases, we will investigate the likelihood of various sequelae and death. Hazard models will be used to estimate the risk of outcomes and their association with the type of foodborne infection. Epidemiological analyses will be conducted to determine the progression of illness and the fraction of sequelae attributable to specific foodborne infections. Economic analyses will assess the consequent direct healthcare costs. ETHICS AND DISSEMINATION: This study has been approved by a University of Waterloo Research Ethics Committee (no 30645), the University of British Columbia Behavioral Research Ethics Board (no H16-00021) and McGill University's Institutional Review Board (no A03-M12-19A). Results will be disseminated via presentations to academics, public health practitioners and knowledge users, and publication in peer-reviewed journals. Where such publications are not open access, manuscripts will also be available via the University of Waterloo's Institutional Repository (https://uwspace.uwaterloo.ca).

Gender differences in the longitudinal association between multilevel latent classes of chronic disease risk behaviours and body mass index in adolescents. / Différences entre les sexes quant à l'association longitudinale entre classes latentes multiniveaux de comportements à risque associés aux maladies chroniques et indice de masse corporelle chez les adolescents.

INTRODUCTION: Few studies have assessed the relationship between chronic disease risk behaviours and body mass index (BMI) in a longitudinal, sex/gender-specific context. This study used gender-specific analyses to assess the extent to which chronic disease risk behaviour latent classes are associated with BMI and weight status at follow-up. METHODS: Longitudinal data from 4510 students in Grades 9 to 12, tracked from 2013- 2015, who participated in the COMPASS study were used to assess gender differences in the lagged association between previously determined latent classes (of physical activity and substance use) with BMI using multilevel mixed-effects models. Our multilevel regression models assessed the association between two latent classes, active experimenters and inactive non-using youth, with BMI when stratified by gender. RESULTS: Male inactive non-substance-using youth were associated with a 0.29 higher continuous BMI (95% CI: 0.057, 0.53) and odds of overweight/obesity increased by 72% (OR = 1.72, 95% CI: 1.2, 2.4) for binary BMI at follow-up relative to active youth who experiment with substance use. No significant associations were detected in females. CONCLUSION: Over time, physical activity has a protective role on BMI in male youth. Both substance use and physical inactivity should be addressed in obesity prevention efforts. Gender stratification in analyses is also important since females and males have different contributing factors to increases in BMI.

Exploring gender differences in the longitudinal association between bullying and risk behaviours with Body Mass Index among COMPASS youth in Canada.

The purpose of this study was to identify gender differences in the association between bullying and Body Mass Index (BMI) longitudinally. Longitudinal data (2013-2015) from 4510 youth (Ontario, Canada) were used to model BMI with consecutive bullying status prospectively, adjusting for previously identified gender-specific health risk behaviour latent classes. To assess for gender differences, these mixed-effects models were stratified by gender. Youth who were victims of bullying (VoB) were more active, engaged in more substance use and reported higher BMI than their non-victim of bullying (NVoB) peers. The gender-specific mixed-models showed that there are gender differences in the association between bullying and BMI. Among females, repeated bullying was associated with higher odds of having overweight/obesity [by 51% (95% C.I. = 1.03, 2.23)] at follow-up. Among male youth, being a VoB at the previous wave only, was associated with higher odds of having overweight/obesity [by 60% (95% C.I. = 1.11, 2.29)] at follow-up. In contrast with previous literature that measured BMI during adulthood (i.e., years after school victimization), our study adds a unique contribution to the literature that across one year (while youth are still in secondary school), bullying is associated with higher odds of weight status and BMI among female and male youth. Since this increase occurs during secondary school, school-based programs aimed at decreasing youth bullying behaviours and addressing increases in BMI before youth leave school are of paramount importance.

Noncomprehensive and Intermittent Obesity-Related School Programs and Policies May Not Work: Evidence from the COMPASS Study.

BACKGROUND: The school environment has the potential to influence student body mass index (BMI) through programs and policies. Our objective was to examine the effect of modifying obesity-related school policies and programs on youths' BMI trajectories. METHODS: Obesity-related school policies and programs related to physical activity and healthy eating were collected from 41 schools across Ontario at baseline (2012-2013) and year 2 (2013-2014) of the COMPASS study. Self-reported height and weight were collected from the 4951 grades 9 and 10 students who attended those schools for 3 years. Linear mixed effects regression models examined the effect of modifying obesity-related school policies and programs on youths' BMI trajectories. RESULTS: Between Y1 and Y2 , 26 of the 41 schools implemented distinct new obesity-related programs or policies related to physical activity or healthy eating. Five of the interventions were associated with BMI trajectories of students attending those schools compared to students attending a pooled sample of control schools, predicting a higher BMI trajectory. CONCLUSIONS: Isolated programs and policies may not successfully improve youths' BMI trajectories. Further research is required to test the implementation of policies and programs that follow a comprehensive school health (CSH) approach, targeting BMI and associated behaviors.

A gender-stratified, multilevel latent class assessment of chronic disease risk behaviours' association with Body Mass Index among youth in the COMPASS study.

This paper sought to examine chronic disease risk behaviour latent classes and their association with Body Mass Index (BMI), assessing for gender differences. Participants were youth (n = 116,086; grades 9-12) enrolled in the COMPASS study (Ontario, Canada) during 2013, 2014, 2015. Multilevel latent class analysis was used to identify underlying, homogenous classes of youths' engagement in physical activity, smoking, binge drinking and marijuana use. Adjusted multilevel models regressed BMI on the latent classes controlling for ethnicity and grade. Three latent classes were identified: active experimenters (ACE), inactive clean youth (INC) and inactive substance users (INSU). This study found that gender differences are apparent in chronic disease risk behaviour latent classes and their association with BMI. INC males (OR = 0.85, 95% CI = 0.78, 0.93) were associated with a lower odds of overweight/obesity relative to active males who experimented with substance use. As for females, the class with the highest proportion of youth using substances were associated with higher odds (Females: OR = 1.2, 95% CI = 1.1, 1.4) of overweight/obesity relative to their active experimenting peers. As such, youth in latent classes with substance use are associated with higher BMI and weight status. Successful interventions may include school policies/programs that limit screen time use, as they were seen to have a positive effect on PA engagement and including social-influences approaches for substance use. Future research and interventions should be gender-specific as our results show that different latent classes are associated with obesity across genders.