Hypertension among adults exposed to drinking water arsenic in Northern Chile

Background: A growing number of studies have identified an association between exposure to inorganic arsenic and hypertension. However, results have not been consistent across studies. Additional studies are warranted, given the global prevalence of both arsenic exposure and morbidity attributable to hypertension. Methods: We analyzed data collected from October 2007-December 2010 for a population-based cancer case control study in northern Chile. Data included lifetime individual arsenic exposure estimates and information on potential confounders for a total of 1266 subjects. Those self-reporting either a physician diagnosis of hypertension or use of an anti-hypertensive medication were classified as having hypertension (n=612). The association between hypertension and drinking water arsenic exposure was analyzed using logistic regression models. Results: Compared to those in the lowest category for lifetime highest 5-year average arsenic exposure (< 60 mu g/L), those in the middle (60-623 mu g/L) and upper (> 623 mu g/L) exposure categories had adjusted hypertension ORs of 1.49 (95% CI: 1.09, 2.05) and 1.65 (95% CI: 1.18, 2.32), respectively. Similar results were observed in analyses of lifetime cumulative exposures and analyses restricted to exposures from the distant past. Conclusions: We identified evidence of increased odds of hypertension with exposure to arsenic in drinking water among study participants. Our findings add to the growing body of research supporting this association, which could have important public health implications.