The association between diabetes and an episode of depressive symptoms in the 2002 World Health Survey: an analysis of 231,797 individuals from 47 countries.

AIMS: Depression is common in people with diabetes and increases the risk of poor health outcomes, including premature mortality. We explored the association between diabetes and an episode of depressive symptoms in a cross-sectional multinational study, which included a large number of low- and middle-income non-Western countries.
METHODS: Data from 47 countries of the 2002 World Health Organization World Health Survey were used, including 231,797 adults (mean age 41 years, 53% female). Diabetes was assessed by self-report of diagnosis or treatment. The presence of an episode of depressive symptoms was assessed by self-report using an algorithm based on DSM-IV criteria. Odds ratios and 95% confidence intervals were calculated to quantify associations between diabetes and episodes of depressive symptoms in the entire sample and for countries aggregated into four continents: Africa, South America, Asia and Europe. Odds ratios were adjusted for age, sex, education, BMI, smoking and physical activity level.
RESULTS: The prevalence of diabetes (mean 3.6%, range 0.2-13%) and episodes of depressive symptoms (mean 7.9%, range 0.4-38%) differed widely across countries. Globally, individuals with diabetes had increased odds of an episode of depressive symptoms compared with those without diabetes (adjusted odds ratio 2.36, 95% confidence interval 1.91-2.92). Similar associations were found in South America, Asia and Europe (odds ratio > 1.97), but not in Africa (odds ratio 0.86, 95% confidence interval 0.54-1.37).
CONCLUSIONS: Globally, diabetes is associated with a twofold increased prevalence of an episode of depressive symptoms, except in Africa. Given the worldwide rise in diabetes in the coming decades, and the increased risk of poor diabetes outcomes associated with co-morbid depression, studies examining mechanisms and interventions are necessary.