The relation of body mass index to depressive symptoms

Data from the 1995 Nova Scotia Health Survey were analyzed to determine the relation between body mass index (BMI) and the risk of depression as measured by the Center for Epidemiological Studies Depression Scale (CES-D).

Clinical measures for height and weight and CES-D scores were available for 2,482 subjects from an initial sample of 5,578 Nova Scotians stratified probabilistically to be representative of age, gender and area of residence. BMIs were categorized according to the international standards (BMI 18.5-24.9 acceptable weight; 25-29.9 overweight; > or = 30 obese).

More men than women were classified as overweight (43.2% vs. 28.3%) but slightly more women than men were obese (25.6% vs. 23.4%). Based on the summary score of the CES-D, 14.2% were categorized as at risk for depression (> or = 16). Logistic regression indicated that lower education (p < 0.001) and income (p < 0.001), and BMI category (p < 0.05) were all significantly related to an increased risk of depression. The odds ratio for the association between obesity and depression, after controlling for education and income, was 1.41 [95% CI = 1.07-1.86].

More studies are needed to ascertain the mechanism by which obesity and depression could be related and the significance of this relation for the prevention and treatment of both obesity and depression. Given the effects of depression, we suggest that health professionals should assess their obese patients for risk of depression before embarking on a weight management protocol.