Association Between Exposure to Low to Moderate Arsenic Levels and Incident Cardiovascular Disease

BACKGROUND Long-term exposure to high levels of arsenic is associated with increased risk for cardiovascular disease, whereas risk from long-term exposure to low to moderate arsenic levels (< 100μg/L in drinking water) is unclear. OBJECTIVE To evaluate the association between long-term exposure to low to moderate arsenic levels and incident cardiovascular disease. DESIGN Prospective cohort study. SETTING The Strong Heart Study baseline visit between 1989 and 1991, with follow-up through 2008. PATIENTS 3575 American Indian men and women aged 45 to 74 years living in Arizona, Oklahoma, and North and South Dakota. MEASUREMENTS The sum of inorganic and methylated arsenic species in urine at baseline was used as a biomarker of long-term arsenic exposure. Outcomes were incident fatal and nonfatal cardiovascular disease. RESULTS A total of 1184 participants developed fatal and nonfatal cardiovascular disease. When the highest and lowest quartiles of arsenic concentrations (> 15.7 vs. < 5.8 μg/g creatinine) were compared,the hazard ratios for cardiovascular disease, coronary heart disease, and stroke mortality after adjustment for sociodemographic factors, smoking, body mass index, and lipid levels were 1.65 (95%CI, 1.20 to 2.27; P for trend < 0.001), 1.71 (CI, 1.19 to 2.44; P for trend < 0.001), and 3.03 (CI, 1.08 to 8.50; P for trend = 0.061),respectively. The corresponding hazard ratios for incident cardiovascular disease, coronary heart disease, and stroke were 1.32 (CI,1.09 to 1.59; P for trend = 0.002), 1.30 (CI, 1.04 to 1.62; P for trend = 0.006), and 1.47 (CI, 0.97 to 2.21; P for trend = 0.032).These associations varied by study region and were attenuated after further adjustment for diabetes, hypertension, and kidney disease measures. LIMITATION Direct measurement of individual arsenic levels in drinking water was unavailable. CONCLUSION Long-term exposure to low to moderate arsenic levels was associated with cardiovascular disease incidence and mortality.