Obesity and the risk of disability in a 12-year cohort study: the role of psychological distress

Purpose Recent cross-sectional findings suggest that co-occurring obesity and psychological problems amplify the risk of disability, but longitudinal evidence is lacking. We assessed this effect in a longitudinal cohort of adults. Methods Twelve years of data (1994/1995–2006/2007) were obtained from the Canadian National Population Health Survey. This study followed 8,062 adults that were interviewed every 2 years. Disability status was derived from the Health Utility Index Mark 3. Covariates of interest were repeated psychological distress (Kessler K6 scale) and obesity (body mass index C30). Incidence of disability was estimated from Cox proportional hazards models, adjusting for sociodemographic and health variables. Hazard rate of disability in those with either obesity (n = 955) or distress (n = 1,044), or both (n = 138) were compared to those without (n = 5,925). Results Participants with both obesity and repeated distress had double the risk of disability compared to those with obesity or distress alone {adjusted hazard ratio of 2.8 [95% confidence interval (CI) 1.8, 4.5] compared to 1.4 (CI 1.1, 1.8) and 1.8 (CI 1.4, 2.3), respectively}. Conclusions Recurrent psychological distress combined with obesity amplified the risk for disability normally associated with these conditions