Traffic-related heavy metals exposure with serum uric acid and hyperuricemia in general Chinese urban adults: Roles of systemic inflammation

The health effects of traffic-derived pollutants have gathered increasing concerns. Our objectives were to evaluate the associations of traffic-related heavy metal exposure with serum uric acid (SUA) and hyperuricemia and to explore the underlying mechanism. Traffic-related heavy metals (including zinc, iron, manganese, copper, lead, cadmium, antimony, and barium) and SUA were determined among 3909 community-based adults from the Wuhan-Zhuhai cohort. Various regression methods were applied to assess the association of heavy metals with SUA and hyperuricemia. Furthermore, mediation analyses were employed to evaluate the potential role of systemic inflammation in these associations. In single metal analyses, positive dose-response relationships between urinary zinc, iron, manganese, and antimony and SUA were observed. Furthermore, each 1-unit increase of ln-transformed urinary zinc levels was related to a 37.9 % (OR=1.379, 95 % CI: 1.148 to 1.657) increase in the hyperuricemia risk. In multiple metal analyses, both Bayesian kernel machine regression (BKMR) and weighted quantile sum regression (WQS) models showed positive associations of heavy metals mixture with SUA and hyperuricemia risk, and WQS analyses further revealed that zinc was the dominant metal (component weight: 0.611 and 0.594, respectively). Additionally, plasma C-reactive protein (CRP) mediated 4.919 % and 8.417 % of the association of urinary zinc with SUA and hyperuricemia, respectively. In conclusion, exposure to several traffic-related heavy metals or traffic-related heavy metal mixture were positively associated with SUA and hyperuricemia risk in the general Chinese population, in which zinc played a dominating role. Plasma CRP might partly mediate the association of urinary zinc with SUA and hyperuricemia risk.