Association Between Depression and Urinary Heavy Metal Levels

Abstract

Introduction: Growing concerns about heavy metal pollution due to urbanization and industrialization have highlighted potential links between heavy metal levels and neurological disorders, including depression. This project aims to investigate the relationship between urinary heavy metal levels and depression status. Methods: The US National Health and Nutrition Examination Survey (NHANES) 2011-2018 data were used. Depression was assessed using a nine-item version of the Patient Health Questionnaire (PHQ-9), with a cut-off point of 10 for depression cases. 13 urinary heavy metals were included. Both univariate analyses, the weighted Wilcoxon test and weighted logistic regression with heavy metal variables transformed into quintiles, and multivariate analyses, Classification and Regression Tree (CART) and random forest, were conducted to investigate the association. Results: The weighted Wilcoxon test found higher levels of cadmium (Cd), antimony (Sb), tin (Sn) and tungsten (Tu) and lower levels of mercury (Hg) and arsenic (As) in the depression group. Weighted logistic regression revealed higher depression risks in the fifth quintile of Cd, the third, fourth and fifth quintiles of Sb, and the third and fifth quintiles of Tu levels. Lower risk was detected in the fifth quintile of As levels. Multivariate analysis identified Sn, Cd, As, cesium (Cs), and thallium (Tl) as crucial metals for classifying depression. Conclusion: In conclusion, this project reveals the complex relationship between urinary heavy metals and depression. Depression was associated with different sets of metals depending on the testing method used, and additional investigation is required to explore the potential interactions.