Objective: Although several cross-sectional studies have linked obesity and depression, less is known about their longitudinal association and about the relative influence of obesity subtypes. We prospectively examined whether obesity (specifically, abdominal) increased the risk of onset of depression in a population-based sample of older persons.
Method: Participants were 2,547 nondepressed, well-functioning white and black persons, aged 70-79 years, enrolled in the Health, Aging, and Body Composition Study, an ongoing prospective community-based cohort study. Baseline measurements were conducted between April 1997 and June 1998. Overall obesity was assessed by body mass index (BMI) and percent body fat (measured by dual energy x-ray absorptiometry), whereas abdominal obesity measures included waist circumference, sagittal diameter, and visceral fat (measured by computer tomography). Onset of significant depressive symptoms was defined as a Center for Epidemiologic Studies Depression 10-item score > or = 10 at any annual follow-up over 5 years and/or new antidepressant medication use. Persistent depression was defined as depression at 2 consecutive follow-up visits.
Results: Over 5 years, significant depressive symptoms emerged in 23.7% of initially nondepressed persons. In men, both overall (BMI: hazard ratio [HR] per SD increase = 1.20; 95% CI, 1.03-1.40) and abdominal obesity (visceral fat: HR per SD increase = 1.19; 95% CI, 1.07-1.33) predicted onset of depressive symptoms after adjustment for sociodemographics. When BMI and visceral fat were adjusted for each other, only visceral fat was significantly associated with depression onset (HR = 1.18; 95% CI, 1.04-1.34). Stronger associations were found for persistent depressive symptoms. No associations were found in women.
Conclusion: This study shows that obesity, in particular visceral fat, increases the risk of onset of significant depressive symptoms in men. These results suggest that specific mechanisms might relate visceral fat to the onset of depression.
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