Urine arsenic and hypertension in US adults: the 2003-2008 National Health and Nutrition Examination Survey.

High chronic exposure to inorganic arsenic may contribute to the development of hypertension. Limited information is available, however, on the association of low to moderate exposure to inorganic arsenic with blood pressure levels and hypertension. We investigated the association of exposure to inorganic arsenic (as measured in urine) with systolic and diastolic blood pressure levels and the prevalence of hypertension in US adults. We studied 4167 adults 20 years of age or older who participated in the National Health and Nutrition Examination Survey (NHANES) from 2003 through 2008 and for whom total arsenic, dimethylarsinate (DMA), and arsenobetaine had been assessed in urine. The median (interquartile range) urine concentrations were 8.3 μg/L (4.2-17.1) for total arsenic, 3.6 μg/L (2.0-6.0) for DMA, and 1.4 μg/L (0.3-6.3) for arsenobetaine. The weighted prevalence of hypertension in the study population was 36%. After multivariable adjustment, a 2-fold increase in total arsenic was associated with a hypertension odds ratio of 0.98 (95% confidence interval = 0.86-1.11). A doubling of total arsenic minus arsenobetaine was associated with a hypertension OR of 1.03 (0.94-1.14) and a doubling of DMA concentrations was associated with a hypertension OR of 1.11 (0.99-1.24). Total arsenic, total arsenic minus arsenobetaine, or DMA levels were not associated with systolic or diastolic blood pressure. At the low to moderate levels, typical of the US population, total arsenic, total arsenic minus arsenobetaine, and DMA concentrations in urine were not associated with the prevalence of hypertension or with systolic or diastolic blood pressure levels. A weak association of DMA with hypertension could not be ruled out.