Blood lead is significantly associated with metabolic syndrome in Korean adults: an analysis based on the Korea National Health and Nutrition Examination Survey (KNHANES), 2008

Background: Although an association between low-level environmental heavy metal exposure and the incidence of metabolic syndrome (MS) has been hypothesized, little research on this topic has been conducted on a population-wide level. Methods: We analyzed MS status and whole blood lead, mercury, cadmium, manganese, and creatinine-adjusted urine arsenic concentrations in 1,405 subjects, >= 20 years of age, who were registered for the Korea National Health and Nutrition Examination Survey, 2008. Results: Various demographic and biochemical parameters were associated with MS and blood heavy metal status. After adjusting for these variables, lead was the only heavy metal that was significantly associated with MS. Lead concentrations in subjects with MS were significantly higher than those in subjects without MS (p = 0.015). The prevalence of MS and a moderate/high risk for cardiovascular disease, as determined by Framingham risk score, also increased significantly according to the logarithmic transformation of the lead quartile (p < 0.001). The odds ratios and 95% confidence intervals for MS were 1.56 (0.90-2.71), 1.63 (0.94-2.83), and 2.57 (1.46-4.51) for the second, third, and fourth quartiles of the log-transformed lead quartile, respectively, as compared with those of the lowest quartile after multiple adjustments for confounding factors. Serum triglyceride level was the only MS diagnostic component significantly associated with lead level in a multiple linear regression analysis (p = 0.006). Conclusions: These findings suggest that a higher prevalence of MS is associated with higher blood lead levels in the Korean population.