Exposure to multiple heavy metals is associated with hypertension: A cross-sectional study in China

Abstract

Abstract Background: Heavy metals may play an important role in hypertension. The aim of this study was to investigate the relationship between hypertension and exposure to manganese (Mn), lead (Pb), copper (Cu), zinc (Zn), cadmium (Cd) and antimony (Sb). Methods: A cross-sectional study of 3,446 subjects was conducted. Logistic regression was used to estimate the relationship between each metal exposure and risk of hypertension. The potential heterogeneity of groups according to sex, age and smoking status was investigated, and metal mixtures and interactions were assessed by Bayesian kernel machine regression (BKMR). Results: The logistic regression analysis identified Cu ([OR]=7.796, 95% [CI]: 3.395-17.903, P <0.001) and Cd (OR=1.894, 95% CI: 1.385-2.592, P <0.001) as risk factors for hypertension. The BKMR analysis indicated that all heavy metals had a complex, nonlinear exposure-response relationship with the risk of hypertension in participants aged 60-99; the stratified analysis of all Cu levels also showed a complex nonlinear relationship. The stratified analysis revealed a significant correlation between the plasma levels of heavy metals and risk of hypertension aged 30-59, nonsmokers, and women. We did not observe any interaction between the hypertensive status of study participants and exposure to the metals, but the logistic regression model revealed possible interactions; we provide explanations for these results. Conclusion: Plasma Cu and Cd levels were positively correlated with risk of hypertension when the metal levels were assessed individually or in combination and may be risk factors for hypertension. Future cohort studies with larger sample sizes and longer follow-up periods are necessary to confirm these associations.