Association between the BMI and depression symptoms in the U.S. older adults base on NHANES

Abstract. Depression ranks among the most prevalent mental health conditions globally, with major depression being more common in elder people. Nonetheless, the link between depressive symptoms and body mass index (BMI) remains ambiguous. The purpose of this study was to investigate the correlation between BMI and symptoms of depression in American elders. In this paper, a cross-sectional study was conducted involving 7,769 participants aged 60 years or older, with all data collected from the 2005-2016 National Health Survey (NHANES). We employed a multivariate logistic regression analysis to evaluate the association between levels of BMI (as independent variables) and presence of symptoms of depression (as outcome variables). Depressive symptoms were primarily assessed using the Patient Health Questionnaire (PHQ-9). Additionally, in this paper, several sensitivity analyses are performed to verify the robustness of our findings. After adjusting for covariates, the final model shows the ORS(95%CI) of underweight and obese people are 1.52(0.78,2.98) and 1.34(0.94,1.93), respectively. And there is a non-linear and U-shaped relationship between the BMI and the depressive symptoms. Both underweight and obese people have a higher incidence of depression in elder people. To validate the association between depression and weight and their causal link, more research is required.