Association of body mass index and depressive symptoms in a Chinese community population: Results from the health promotion knowledge, attitudes, and performance survey in Taiwan

Background: The association between obesity and depression remains equivocal. The aims of this study were to examine the association between body mass index (BMI) and depressive symptoms in the Chinese adult population. Methods: In this study, data from the Health Promotion Knowledge, Attitudes, and Performance Survey, conducted in 2002 among 20,385 Taiwanese adults (aged 18-64 years), were used. Depressive symptoms were assessed by the Taiwanese Depression Questionnaire (cut off point 19). Weight status was categorized as underweight (BMI < 18.5 kg/m ²), normal weight (BMI 18.5- 23.9 kg/m ²), overweight (BMI 24-26.9 kg/m ²), and obese (BMI ≧ 27 kg/m ²). Results: Bivariate analyses revealed that underweight men and women had higher risks of depressive symptoms than normal weight individuals. After controlling for education, income, occupation, smoking status, marital status, presence of chronic disease, exercise, and weight control measures, we found that underweight men were significantly more likely to have depressive symptoms than normal weight men (Adjusted odds ratio [AOR] 2.68, 95% confidence interval [CI] 1.85-3.88). On the contrary, obese women were significantly less likely to have depressive symptoms than normal weight women (AOR 0.62, 95% CI 0.46-0.83). Conclusion: The associations of BMI and depressive symptoms were different between genders. Underweight men ran a higher risk of depression than normal weight men, and overweight women had a lower risk than normal weight women. These findings support the "jolly fat" hypothesis among the adult population in the Chinese community.