Association of Geography and Ambient Air Pollution with Urine Metal Concentrations in Six US Cities: The Multi-Ethnic Study of Atherosclerosis

We investigated the associations of urinary concentrations of antimony, cadmium, tungsten and uranium with geographic locations and with ambient air pollution in 304 adults in the Multi-Ethnic Study of Atherosclerosis from six US cities. After adjustment for sociodemographics, body mass index, and smoking status, urinary cadmium was the highest in Winston-Salem among all study sites (the geometric mean [GM] in Winston-Salem was 0.84 µg/L [95% confidence interval (CI) 0.57-1.22]). The adjusted GMs of urinary tungsten and uranium were highest in Los Angeles (0.11 µg/L [95% CI 0.08-0.16] and 0.019 µg/L [95% CI 0.016-0.023], respectively). The adjusted GM ratio comparing fine particulate matter (PM2.5) tertiles 2 and 3 with the lowest tertile were 1.64 (95% CI 1.05-2.56) and 3.55 (95% CI 2.24-5.63) for tungsten, and 1.18 (95% CI 0.94-1.48) and 1.70 (95% CI 1.34-2.14) for uranium. The results for tungsten remained similar after adjustment for study site. Urinary cadmium, tungsten and uranium concentrations differed by geographic locations in MESA (Multi-Ethnic Study of Atherosclerosis) communities. PM2.5 levels could contribute to geographic differences in tungsten exposure. These findings highlight the need to implement preventive strategies to decrease toxic metal exposure and to evaluate the health effects of chronic exposure to those metals.