Association between Past Body Mass Index, Weight Change and Self-reported Depression in the Health Examinees Study (HEXA)

Abstract

Background: Although several studies have focused on the relationship between obesity and depression, far fewer studies have examined underweight or weight change and depression over time. Furthermore, the association between body size, weight change and depression has not been systematically summarized, particularly for underweight individuals. Objective: This study consists of a meta-analysis that evaluates the association between indices for body size and depression. Furthermore, this study assesses the relationship between weight change and subsequent depression. In a Health Examinees (HEXA) study, our objective was to explore the association between body mass index (BMI), weight change and depression considering the interaction between baseline BMI and consequent weight change and this interactions effect on depression. Materials and methods: A computerized systematic literature search was conducted in PubMed, EMBASE and the Cochrane Library for studies published before March 10, 2015

no language restrictions were applied. A total of 183 studies focusing on the relationship between body size, weight change and depression were selected by 5 individual researchers with crosschecking. Fully adjusted hazard ratios (HRs) or odds ratios (ORs) were extracted. Random-effect models were used to synthesize the data from the studies, and we performed subgroup analyses to examine the effects of potential moderators (gender, age, continent of residence and comorbidities). In the HEXA study, a total of 168,123 out of 170,087 participants were included in the final analysis. Every participant was interviewed regarding their demographic factors, medical histories, health behaviors and diet. The participants were required to recall their weight at various time points. Trained staff measured the participants weight and height. BMI at each time point was calculated, and weight change was measured in 2 manners: 1) from age 18-20 to the present time, and 2) from lowest to highest weight considering age at which that weight occurred. The outcome was measured using 2 working definitions: 1) depression diagnosis by a physician after the weight recall, and 2) the Center for Epidemiological Studies-Depression Scale. ORs were calculated utilizing multivariate logistic regression. Possible interactions between baseline BMI and consequent weight change were assessed. Results: In a meta-analysis of the cohort studies, being underweight (BMI<18.5 kg/m2) at baseline increased the risk of subsequent depression (OR 1.16, 95% CI 1.08-1.24). Overweight participants (BMI 25-29.9 kg/m2) showed no statistically significant results overall

however, the subgroup analyses presented different results according to gender. In men, the pooled ORs showed a protective effect of being overweight on depression (OR 0.84, 95% CI 0.72-0.97), whereas women presented opposite results (OR 1.16, 95% CI 1.07-1.25). The risk for depression marginally increased (OR 1.13, 95% CI 0.96-1.34) in the obese (BMI≥30 kg/m2). Participants with a greater waist circumference (WC, >102 cm [men] and >88 cm [women]) presented a significantly increased risk of depression (OR 1.38, 95% CI 1.17-1.62). In the cross-sectional studies, obesity with a BMI of over 40 kg/m2 showed a greater pooled OR (OR 1.59, 95% CI 1.12-2.24) than obesity with a BMI of over 30 kg/m2 (OR 1.18, 95% CI 1.11-1.26). Both weight gain and weight loss showed marginally significant ORs for subsequent depression. In the HEXA results, 2.2% (3,623/168,123) of participants reported ever having been diagnosed with depression. Men in the underweight population mostly showed a significantly increased OR (OR 3.08, 95% CI 1.22-7.79 at age 50). Women who were underweight at age 35 showed an increased OR (OR 1.27, 95% CI 1.08-1.50). The OR was significantly decreased in obese I men (OR 0.61, 95% CI 0.42-0.88 at 2 years before the survey), overweight at risk women (OR 0.88, 95% CI 0.79-0.98 at age 35) and obese I women (OR 0.86, 95% CI 0.76-0.97 at age 35). The participants who gained large amounts weight or the women who lost weight showed a significantly increased OR. Assessing the joint association showed significantly increased likelihoods among 1) participants who were underweight at age 18-20 with relatively stable weight (men: OR 2.11, 95% CI 1.31-3.38

women: OR 1.21, 95% CI 1.04-1.40) and 2) women who had a normal BMI at age 18-20 with subsequent weight loss (OR 1.39, 95% CI 1.14-1.70). Conclusions: In the results of both the meta-analysis and the HEXA study, underweight people were associated with an increased likelihood of later depression. Additionally, people who gained large amounts of weight and women who lost weight had increased ORs for depression. The likelihood for depression increased for people who were underweight in early adulthood (age 18-20) and maintained a relatively stable weight.