Impact of multi-metal exposure on blood pressure: a mediation analysis through oxidative stress markers in China's Southern Jiangxi Province

Abstract

Hypertension is a prevalent condition that contributes significantly to the global disease burden. Recent research endeavors have been investigating the potential causal link between metal exposure and the development of hypertension, yet consensus remains elusive. Nevertheless, studies examining the interplay among metal exposure, hypertension, and oxidative stress are relatively limited. This study utilized data from a cross-sectional survey conducted in southern Jiangxi Province, China. We evaluated urinary concentrations of 19 metals, including aluminum and manganese, in conjunction with measurements of systolic and diastolic blood pressures, as well as three oxidative stress biomarkers: glutathione peroxidase (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA). In the monometallic model, chromium, iron, manganese, and molybdenum exhibited positive correlations with blood pressure. These findings were consistent in the mixed exposure model. Conversely, all the aforementioned metals exhibited a negative correlation with GSH and SOD, while demonstrating a positive correlation with MDA. Mediation effect analysis revealed that GSH and SOD mediated the relationships between urinary concentrations of aluminum, iron, manganese, and antimony and blood pressure. In contrast, MDA mediated the associations between urinary silver and antimony and blood pressure. Furthermore, GSH and SOD were identified as mediators in part of the relationship between mixed metal exposure and blood pressure, with mediation rates of 19.09% for GSH and 27.36% for SOD. The results of this study suggest that exposure to both individual and combined metals effects blood pressure levels, which are further associated with changes in oxidative stress levels. Moreover, oxidative stress levels may modulate the changes in blood pressure related to metal exposure, providing a basis for further investigation into the health risks associated with these metal exposures.

Keywords: BKMR; Blood pressure; Mediation analysis; Oxidative stress; Urinary metals.

Fig. 1

Single-metal regression model of metal concentrations and levels of oxidative stress indicators. Both metal concentrations and oxidative stress indicators were ln transformed. GSH, Glutathione; SOD, Superoxide Dismutase; MDA, Malondialdehyde. All models were based on age, sex, body mass index, smoking, alcohol consumption, education, household income, and occupation

Fig. 2

Mediating effects of GSH on the correlation between mixed metal levels and blood pressure. SBP, Systolic blood pressure; GSH, Glutathione; All models were adjusted for age, sex, body mass index, smoking, alcohol consumption, education, household income and occupation. Both metal concentrations and oxidative stress indicators were ln transformed

Fig. 3

Mediating effects of SOD on the correlation between mixed metal levels and blood pressure. SBP, Systolic blood pressure; SOD, Superoxide dismutase; All models were adjusted for age, sex, body mass index, smoking, alcohol consumption, education, household income and occupation. Both metal concentrations and oxidative stress indicators were ln transformed

Fig. 4

Mediating effects of MDA on the correlation between mixed metal levels and blood pressure. SBP, Systolic blood pressure; MDA, Malondialdehyde; All models were adjusted for age, sex, body mass index, smoking, alcohol consumption, education, household income and occupation. Both metal concentrations and oxidative stress indicators were ln transformed