Abstract
BACKGROUND: Obesity has been longitudinally associated with depression but only few studies take a life course approach. This longitudinal study investigates whether being overweight or obese at age 8 and 13 years is associated with depressive symptoms more than 60 years later and whether this association is independent of late-life body mass index (BMI). We also investigated the association of being overweight/obese at age 8 or 13 years with ever having major depressive disorder (lifetime MDD). METHOD: This analysis is based on a sub-sample of 889 AGES-Reykjavik participants with measured BMI data from early life. Late-life depressive symptoms were measured with the Geriatric Depression Scale (GDS) and lifetime MDD was assessed at late-life using the Mini International Neuropsychiatric Interview. Logistic regression analysis was used to estimate the relationships between BMI (continuous and categorical) at age 8 or 13 years, and late-life depressive symptoms (measured as GDS ≥ 5) or lifetime MDD, adjusted for sex, education, physical activity, smoking status and alcohol use. In a separate model, additional adjustments were made for late-life BMI. RESULTS: One hundred and one subjects (11%) had depressive symptoms at late-life (GDS ≥ 5), and 39 subjects (4.4%) had lifetime MDD. Being overweight or obese at age 8 or 13 years was not associated with higher depressive symptoms during late-life, irrespective of late-life BMI. Being overweight or obese at age 8 years, but not age 13 years was associated with an increased risk of lifetime MDD (Odds Ratio (OR) (95% confidence interval [CI]) for age 8 = 4.03[1.16-13.96]P = 0.03 and age 13 = 2.65[0.69-10.26] P = 0.16, respectively). CONCLUSION: Being overweight in childhood was associated with increased odds of lifetime MDD, although the magnitude of the risk is uncertain given the small numbers of participants with lifetime MDD. No clear association was observed between childhood and adolescent overweight/obesity and late-life depressive symptoms irrespective of late life BMI.