Toxic Metal Exposures and C-Reactive Protein among US non-smoking adults: NHANES 1999-2010

Few studies on environmental metal exposures have been conducted among non-smokers, and few have examined interaction effects from exposure to more than one metal. The objectives of this study were 1) to test the hypothesis that metal exposure (including barium, cadmium, cobalt, cesium, molybdenum, lead, antimony, thallium, and tungsten) would be associated with the inflammatory marker C-reactive protein (CRP) among non-smoking adults aged 19 or older, and 2) to explore interaction effects among these metals. We used data from the National Health and Nutrition Examination Survey (NHANES) 1999-2010. The dependent variable was a clinically raised CRP level >1.00 mg/dl. Among 4,738 non-smoking adults, urinary cadmium and antimony were associated with elevated CRP in a dose-dependent fashion (p for trend <0.001 for both metals) adjusting for age, gender, race and obesity. The adjusted odds ratio for elevated CRP comparing the fourth quartile to the first quartile of the cadmium distribution was 1.92 (95% confidence interval [CI], 1.17-2.53); that for antimony was 1.72 (95% CI 1.17-2.53). The adjusted odds ratio for elevated CRP was significant in the third quartile of tungsten and remained marginally but non-significantly increased for the fourth quartile compared with the first quartile. Elevated CRP was not associated with other selected metals. We did not find evidence that interactions among pairs of metals increased risk of elevated CRP. Environmental exposures to cadmium, antimony and tungsten that are not confounded by personal smoking behavior seem to promote an inflammatory response.