Low- and moderate- levels of arsenic exposure in young adulthood and incidence of chronic kidney disease: findings from the CARDIA Trace Element Study

Abstract Background It is unclear whether arsenic exerts adverse health effects on the kidney at low- and moderate- levels of exposure. We prospectively examined toenail arsenic concentrations measured during young adulthood in relation to incidence of chronic kidney disease (CKD) in midlife. Methods A total of 3,768 participants (53% female and 48% blacks) in the Coronary Artery Risk Development in Young Adults (CARDIA) study were included. Arsenic concentration in toenail clippings was assessed by using inductively coupled plasma mass spectrometry at CARDIA exam year 2. Incident CKD was identified if having estimated glomerular filtration rate 30 mg/g. The association between toenail arsenic levels and CKD incidence over a mean of 24 years of follow-up was examined using multivariable-adjusted Cox proportional hazards models. Results After controlling for potential confounders, including demographics, socioeconomics, lifestyle factors, clinical measurements of blood pressure, lipids, and glucose, and medical history, arsenic exposure measured in toenails was not associated with CKD incidence (quintile 5 versus quintile 1: hazard ratio = 1.04, 95% confidence interval = 0.78-1.40, P for trend = 0.38). Conclusion The null association was not modified by sex or race. This longitudinal study does not support the hypothesis that low- and moderate- levels of arsenic exposure are associated with elevated incidence of CKD in the US general population. Further studies are need to investigate species of arsenic biomarkers in relation to nephrotoxicity.