Total Blood Mercury Levels and Depression among Adults in Korea: Korea National Health and Nutrition Examination Survey 2010–2013

Abstract

Background: Depression is a significant public health problem in Korea, and high levels of exposure to the known neurotoxicant mercury can elicit neuropsychiatric symptoms. Many studies further suggest that chronic low-level exposure to mercury can be linked to depression, though this association remains unclear. Methods: Cross-sectional associations between cases and symptoms of depression and total blood mercury levels were assessed in 7,624 adults as part of the Korea National Health and Nutrition Examination Survey 2010–2013. The likelihood of receiving a diagnosis of depression in relation to the level of mercury in the blood was calculated as an odds ratio (OR) using multivariable logistic regression analysis. Similarly, the likelihood of experiencing depressive symptoms was also calculated. Results: Logistic regression analysis revealed no association between total blood mercury levels and cases of depression. With regard to depressive symptoms, logistic regression analysis of the unadjusted survey data revealed that higher total blood mercury levels were associated with a lower incidence of depression when data from the <25% and 25%–50% mercury quartiles (OR, 0.743; 95% confidence interval [CI], 0.851–0.951) were compared with data from the <25% and 50%–75% mercury quartiles (OR, 0.686; 95% CI, 0.535–0.880). However, this association disappeared for the ≥75% mercury quartile. Furthermore, no association was observed after adjusting for confounding variables. Conclusion: Based on the results of our statistical analyses, we conclude that no association exists between total blood mercury levels and depression status/depressive symptoms in Korean adults.