Urine Arsenic and Prevalent Albuminuria: Evidence From a Population-Based Study

Background: Long-term arsenic exposure is a major global health problem. However, few epidemiologic studies have evaluated the association of arsenic with kidney measures. Our objective was to evaluate the cross-sectional association between inorganic arsenic exposure and albuminuria in American Indian adults from rural areas of Arizona, Oklahoma, and North and South Dakota. Study Design: Cross-sectional. Setting & Partipants: Strong Heart Study locations in Arizona, Oklahoma, and North and South Dakota. 3,821 American Indian men and women aged 45-74 years with urine arsenic and albumin measurements. Predictor: Urine arsenic. Outcomes: Urine albumin-creatinine ratio and albuminuria status. Measurements: Arsenic exposure was estimated by measuring total urine arsenic and urine arsenic species using inductively coupled plasma mass spectrometry (ICPMS) and high-performance liquid chromatography-ICPMS, respectively. Urine albumin was measured by automated nephelometric immunochemistry. Results: The prevalence of albuminuria (albumin-creatinine ratio >= 30 mg/g) was 30%. Median value for the sum of inorganic and methylated arsenic species was 9.7 (IQR, 5.8-15.6) mu g per gram of creatinine. Multivariable-adjusted prevalence ratios of albuminuria (albumin-creatinine ratio >= 30 mg/g) comparing the 3 highest to lowest quartiles of the sum of inorganic and methylated arsenic species were 1.16 (95% CI, 1.00-1.34), 1.24 (95% CI, 1.07-1.43), and 1.55 (95% CI, 1.35-1.78), respectively (P for trend <0.001). The association between urine arsenic and albuminuria was observed across all participant subgroups evaluated and was evident for both micro-and macroalbuminuria. Limitations: The cross-sectional design cannot rule out reverse causation. Conclusions: Increasing urine arsenic concentrations were cross-sectionally associated with increased albuminuria in a rural US population with a high burden of diabetes and obesity. Prospective epidemiologic and mechanistic evidence is needed to understand the role of arsenic as a kidney disease risk factor. Am J Kidney Dis. 61(3):385-394. (C) 2013 by the National Kidney Foundation, Inc.