Environmental exposures to lead, mercury, cadmium, manganese, and arsenic and obesity in Korean adults: Korean National Environmental Health Survey 2009–2017

BACKGROUND: Obesity in adults has substantially increased, and the proportion of obese adults worldwide is estimated to exceed 50 % by 2030. OBJECTIVE: This study aims to evaluate the association between heavy metal exposure and obesity in the general adult population in Korea. METHODS: We used data from 14832 general adults from the Korean National Environmental Health Survey (KoNEHS) 2009-2017 with measures of heavy metals in blood and urine samples. Survey linear regression or survey logistic regression models were performed to assess the associations of blood lead, cadmium, and mercury, and urine arsenic and manganese with body mass index or obesity. RESULTS: After adjustment for confounders, participants in the highest quintile of blood lead and mercury had significantly higher odds of obesity compared to those in the lowest quintile (OR: 1.22 (95 % CI: 1.07-1.44); 2.17 (95 % CI: 1.87-2.51)) with dose-response relationships (both P for trend < 0.001). For blood manganese, participants in the third quintile had significantly higher odds of obesity (1.33 (95 % CI: 1.06-1.67)). There was a marginally significant increase in odds of underweight among those in the third quintile of urine arsenic compared to those in the lowest quintile (1.43 (95 % CI: 0.77-2.66)). There was no association between the quintiles of urine cadmium and arsenic levels and obesity. CONCLUSION: We provide evidence of a dose-response association between lead and mercury exposure and an increased risk of obesity in Korean adults. Exposure to manganese at moderate concentrations was associated with obesity. In addition, exposure to arsenic was marginally associated with an increased risk of underweight. Additional prospective studies are required to elucidate the effects of heavy metals on obesity.