Effects of nutritional measures on toenail arsenic concentration as a biomarker of arsenic exposure

Abstract

Correlations between drinking water and toenail arsenic concentrations have been demonstrated in previous studies, yet factors that may modify the exposure–biomarker association have not been adequately assessed. Using data from 500 controls enrolled in a bladder cancer study underway in Michigan, USA, the effects of demographic characteristics and nutritional measures on the biomarker response were evaluated. Drinking water and toenail samples were collected during a home visit and analyzed for arsenic and other elements. Participants reported dietary supplement intake habits and provided demographic data. Arsenic concentrations of drinking water and toenail samples were positively correlated. Of the nutritional measures evaluated, toenail iron concentration was a significant modifier of the exposure–biomarker association. No demographic characteristics or general measures of dietary intake affected the biomarker response. The results presented herein are critical for biomarker validation and prove promising for sound application of the arsenic toenail biomarker to future epidemiological investigations.