Association between obesity and depression in Canadians

To determine the age and sex variations in the associations between obesity and depression.

This analysis was based on data from 59,652 adults >or=18 years of age in the provinces of Nova Scotia, Quebec, Saskatchewan, Alberta, and British Columbia, who participated in the Canadian Community Health Survey conducted in 2005. The survey included a set of 27 questions about symptoms of depression, which were taken from the Composite International Diagnostic Interview. Based on these questions, depression scores were calculated and used to define depression, which corresponds to a 90% likelihood of a positive diagnosis of major depressive episode. Body weight and height were based on self-report.

The prevalence of depression was 5.3% in adults living in the five provinces and was higher in women than in men. People with abnormal body weight tended to have an increased risk of depression. On average, obesity and being underweight were associated with approximately 30% and 40% increases in depression, respectively. Particularly in women, depression was more markedly associated with obesity in the 18-39 year age group (OR 1.67, 95% CI 1.29-2.15) and with being underweight in the 40-59 year age group (OR 2.23, 95% CI 1.45-3.42) than other age groups.

Obesity is associated with an increased risk of depression in younger women.