The interaction of obesity and psychological distress on disability

Prior research has shown that psychological problems interact with various chronic medical conditions to amplify disability, but no study has investigated this effect in obesity. The aim of this study was to evaluate the synergistic interaction of psychological distress and obesity on functional disability in an adult community sample. Cross-sectional data were obtained from the 2005 Canadian Community Health Survey, a nationally representative sample of 53,416 respondents aged 18 years or older. Our outcome measures were self-reported disability days and self-rated health. Our covariates of interest were non-specific psychological distress (Kessler K10 scale) and body mass index (BMI). Odds ratios of disability measures were estimated by psychological distress and weight status from logistic regressions, adjusted for sociodemographic and clinical variables. Disability status was more frequent in individuals with obesity and psychological distress than in those with either obesity or psychological distress alone. Adjusted odds ratios increased progressively across BMI and psychological distress categories. Significant interactions were found for (a) obesity class I (BMI between 30.0 and 34.9 kg m(-2)) and high psychological distress; and (b) obesity class II-III (BMI > 35 kg m(-2)) and moderate to high distress. The results suggest a strong association between psychological distress, obesity and disability. Addressing psychological distress in obese individuals might reduce the public health burden of comorbid obesity and psychological distress by tackling disability.