Association of urinary metal profiles with serum uric acid: a cross-sectional study of traffic policemen in Wuhan, China

OBJECTIVES: Serum uric acid (SUA) is both a strong antioxidant and one of the key risk factors of cardiovascular diseases (CVDs). We aimed to investigate the associations of urinary metal profile with SUA in traffic policemen in Wuhan, China. DESIGN: A cross-sectional study was carried out in traffic policemen. SETTING: A seriously polluted Chinese city. PARTICIPANTS: A total of 186 traffic policemen were recruited in this study. About 56 of them worked in the logistics department and the other 130 maintained traffic order or dealt with traffic accidents on the roads. All these subjects had worked as a policeman for at least 1 year. MAIN OUTCOME MEASURES: SUA. RESULTS: The significantly negative association of lead with SUA was consistent between single-metal and multiple-metal models (p=0.004 and p=0.020, respectively). Vanadium, chromium and tin were reversely associated with SUA levels in the single-metal models after false discovery rate (FDR) adjustment (all P (_FDR) < 0.05). One IQR increase in vanadium, chromium, tin and lead was associated with 26.9 µmol/L (95% CI −44.6 to −9.2; p=0.003), 27.4 µmol/L (95% CI −46.1 to −8.8; p=0.004), 11.2 µmol/L (95% CI −18.9 to −3.4; p=0.005) and 16.4 µmol/L (95% CI −27.6 to −5.2; p=0.004) decrease in SUA, respectively. Significant interaction between smoking and vanadium on decreased SUV was found (p(for interaction) = 0.007 and p(_FDR) = 0.028). CONCLUSIONS: Urinary vanadium, chromium, tin and lead were negatively associated with SUA. Vanadium and cigarette smoking jointly affected SUA levels. Further studies are needed to replicate these findings and to investigate the potential mechanisms.