Prevalence of obesity and elevated body mass index along a progression of rurality: A cross-sectional study - The Canadian Longitudinal Study on Aging.

Introduction: Obesity is an important public health concern, and large studies of rural-urban differences in prevalence of obesity are lacking. Our purpose is to compare body mass index (BMI) and obesity in Canada using an expanded definition of rurality.

Methods: A cross-sectional analysis of self-reported BMI across diverse communities of Canadians aged 45-85 years was conducted using data from the Canadian Longitudinal Study on Aging (CLSA), a national sample representative of community-dwelling residents. Rurality was identified in the CLSA based on residential postal codes, which were divided into 4 categories: urban, peri-urban, mixed and rural. Logistic regression models were constructed to calculate adjusted odds ratios (aORs) with 95% confidence intervals (95% CIs) between obesity (BMI ≥30 kg/m2 from self-reported weight and height) and rurality, adjusting for age, sex, province, marital status, number of residents in household and household income.

Results: Twenty-one thousand one hundred and twenty-six Canadian residents aged 45-85 years, surveyed during 2010-2015, were included. 26.8% were obese. Obesity was less prevalent amongst urban (25.2%) than rural (30.3%, P < 0.0001), mixed (28.7%, P < 0.0001) or peri-urban communities (28.1%, P < 0.0001). When compared to urban areas, the aOR (95% CI) for obesity was 1.09 (1.00-1.20) in rural regions and 1.20 (1.08-1.35) in peri-urban settings. In areas of mixed urban and rural residence, the aOR was 1.12 (0.99-1.27).

Conclusion: One in four Canadian adults were obese. Living in a non-urban setting is an independent risk factor for obesity. Rural-urban health disparities could underlie rural-urban differences, but further research is needed.