Effect of combined exposure to lead, mercury, and cadmium on hypertension: The 2008-2013 Korean National Health and Nutrition Examination Surveys.

Objectives: Many studies have demonstrated the effects of heavy metals on hypertension. However, to date, no study has used the Korean National Health and Nutrition Examination Survey (KNHANES) to analyze the effects of combined exposure to heavy metals on hypertension. Therefore, this study inferred the study population using weights based on a rolling sample and used standardized scores to estimate the effects of combined exposure to heavy metals on hypertension.

Material and methods: The authors used raw participant data from KNHANES (2008-2013), when heavy metal levels in the blood were measured. The authors analyzed the effects of lead, mercury, and cadmium on hypertension. The authors calculated standardized scores based on a regression analysis to analyze the effects of combined exposure. The odds ratios (ORs) of hypertension due to heavy metals were calculated using multivariate logistic regression, with the lowest quartile as the reference category.

Results: In the crude regression analysis, lead, mercury, and cadmium exposure were associated with significant differences in the rate of hypertension (p < 0.05). However, when other heavy metals were included as covariates, only lead (OR = 1.29, 95% confidence interval [CI]: 1.08-1.55) and cadmium (OR = 1.47, 95% CI: 1.24-1.74) showed significant effects (p < 0.01). When the authors analyzed the effects of combined exposure to heavy metals, the OR of hypertension for the highest quartile, relative to the lowest quartile, was 1.78 (95% CI: 1.50-2.11, p < 0.001). Linear regression analysis revealed that heavy metal exposure was significantly associated with hypertension prevalence (p < 0.001).

Conclusions: This study verified that heavy metal exposure affects the prevalence of hypertension and that combined exposure to multiple heavy metals is associated with a higher risk of hypertension than exposure to a single heavy metal. Further research is necessary to screen for heavy metal-related risk factors and evaluate whether the interactions between heavy metals are positive or negative. Int J Occup Med Environ Health. 2025;38(3):264-279.