Heavy metals exposure is associated with early liver dysfunction among rural residents aged 40-75 years in southwest China

Heavy metals exposure has been associated with liver dysfunction in recent reports, while the hepatoxicity of lead (Pb) and cadmium (Cd) has been well established. However, the combined effects of multi-metal in real-world scenario on liver dysfunction are still unclear. This cross-sectional study examined associations between 10 biomarkers of early liver injury and multiple heavy metals levels. The levels of heavy metals/metalloid (magnesium [Mg], calcium [Ca], iron [Fe], zinc [Zn], arsenic [As], Cd, copper [Cu], and Pb) were measured in blood and urinary sample collected from 725 participants in a Cd-polluted area and an unpolluted area in southwest China. The early liver dysfunction biomarkers included the liver enzymes (ALT, ALP, AST, and GGT), proteins (TP, ALB, and GLO), and bilirubin (TBIL, DBIL, and IBIL). Confounder-adjusted beta coefficients were determined using multiple linear regression model analysis for the group-classified and gender-classified samples. Our results showed that blood Fe, Cd, and Cu levels were found to be positively related to elevated ALT levels and blood Cu was positively associated with AST levels in the Cd-polluted area, while the highest blood Zn quartile in the polluted area and blood Mg quartile in the unpolluted area were associated with lower ALT levels. Our finding implies that industrial pollution results in heavy metals of Cd and Pb exposure and effects of Fe, Cd, Cu, and Pb in the Cd-polluted area may be the main contributors to increase the risk of liver dysfunction while Zn in the Cd-polluted area and Mg in the unpolluted area may be the protective factors.

Automated summary

This study investigated the impact of cadmium exposure on liver function, finding that blood levels of iron, cadmium, and copper were positively correlated with elevated ALT levels, while blood copper was positively associated with AST levels. Additionally, the highest blood zinc quartile in the polluted area and blood magnesium quartile in the unpolluted area were associated with lower ALT levels.