ABSTRACT
BACKGROUND: Several conflicting studies exist on the relationship between body mass index (BMI) and depression. We investigated the effect of BMI on the development of depression in adults aged 45 years and older using the Korean Longitudinal Study of Aging Study (KLoSA).METHODS: The data from the wave 1 (2006), wave 2 (2008), wave 3 (2010), wave 4 (2012), and wave 5 (2014) database of the Korean Longitudinal Study on Aging (KLoSA) were analyzed. Depression was assessed using the Center for Epidemiologic Studies Depression Scale-10. To investigate the relationship between BMI and depression, ANOVA and chi-square test was used. Kaplan-Meier survival curves were generated, and Cox proportional hazard regression modeling was used to estimate the risk of depression according to obesity status, by controlling for age, sex, and health-related, lifestyle, and socioeconomic variables.RESULTS: This study included 6,811 individuals who were not found to have depression in the first survey. The incidence of depression was the highest in the underweight group (underweight, 74.3%; normal, 63.1%; overweight, 59.5%; obese, 63.0%; severe obese, 59.9%, P < 0.001). The risk of depression was significantly lower in the overweight and severe obese groups than in the underweight group after adjusting for age, sex, and demographic, social, and physical factors (overweight: hazard ratio [HR]=0.872, 95% confidence interval [CI]=0.775–0.981; severe obese: HR=0.791, 95% CI=0.648–0.966).CONCLUSION: The incidence of depression was the highest in the underweight group. The risk of depression was higher in the underweight group than in the overweight and severe obese groups.