Associations of Mixed-Metal Exposure with Hyperuricemia Risk in an Occupational Population: A Nested Case–Control Study in the Jinchang Cohort

(1) Background: Hyperuricemia (HUA) has become an increasingly important global public health concern. Workers in non-ferrous metal mining and smelting industries may be exposed to multiple metals through occupational activities. This study aimed to investigate the associations between mixed-metal exposure and the risk of incident HUA in an occupational population using a nested case–control design within the Jinchang Cohort. (2) Methods: Plasma samples from 2000 participants from Jinchuan Group Co., Ltd. were available for metal measurement, of whom 1722 participants with complete data were included in the final analysis, comprising 333 incident HUA cases and 1389 controls. Eleven metals, including lithium (Li), aluminum (Al), titanium (Ti), strontium (Sr), vanadium (V), chromium (Cr), copper (Cu), zinc (Zn), iron (Fe), arsenic (As), and selenium (Se), were analyzed. Multivariable logistic regression and restricted cubic spline (RCS) models were applied to evaluate the associations between individual metal exposures and HUA risk. Bayesian kernel machine regression (BKMR) and weighted quantile sum (WQS) regression models were used to assess the associations between metal mixtures and HUA risk. (3) Results: Individual metal analyses indicated that Al, Sr, and V exposures were positively associated with HUA risk, whereas Se exposure was inversely associated with HUA risk. Both BKMR and WQS models demonstrated a positive association between mixed-metal exposure and HUA risk, with V and Sr identified as major contributors to the mixture effect. (4) Conclusions: Occupational exposure to metal mixtures was associated with an increased risk of HUA, with V and Sr playing important roles in the overall mixture effect. These findings highlight the potential health impacts of mixed-metal exposure on HUA development among occupational populations.