Metals Exposure, Biological Aging and Metabolic Syndrome: Exploring the Associations and Mediation Effects.

Metals disequilibrium is crucial in the progress of metabolic syndrome (MetS), whereas the underlying mechanism remains largely unclear. Aging is closely related with the major diseases, and recent studies show environmental exposure also accelerate aging. Therefore, we aimed at investigating the mediation impact of biological age (BA) on relationships of metals exposure with MetS risk. A cross-sectional study with 1,504 participants was conducted. BA predictors were established by Klemera and Doubal method (KDM) and Mahalanobis distance, based on clinical measures. KDM-accel [the residual difference of regressing KDM-BA to chronological age] and physiological dysregulation (PD) were further calculated and recorded as biological aging indexes (BAIs). Seven plasma metals (calcium, cobalt, copper, magnesium, molybdenum, selenium, and zinc), reported to be linked with MetS in our preceding study, were involved. Multivariate linear and logistic regression models were performed to evaluate the relationships of BAIs with metals exposure or MetS risk, respectively. The mediation effect of BA linking metals to MetS was also explored. Quantiles of magnesium, molybdenum, and cobalt showed significant negative relationships with MetS risk and two BAIs (all p-trend<0.05). Significant positive associations were observed for two BAIs and MetS risk (p<0.001). Mediation analysis showed that BAIs mediated 19.15% and 13.23% of the negative associations between plasma molybdenum, magnesium and MetS risk, respectively. Our findings suggested that essential metals might reduce MetS risk via decelerating biological aging, emphasizing the significance of essential metals in prevention of aging and MetS.