Hypertension and arsenic exposure in Bangladesh

A prevalence comparison of hypertension among subjects with and those witho ut arsenic exposure through drinking water was conducted in Bangladesh to c onfirm or refute an earlier observation of a relation in this respect. Well s with and without present arsenic contamination were identified, and we in terviewed and examined 1595 subjects who were depending on drinking water f rom these wells for living, all greater than or equal to 30 years of age. T he interview was based on a questionnaire, and arsenic exposure was estimat ed from the history of well-water consumption and current arsenic levels. O f the 1595 subjects studied, 1481 had a history of arsenic-contaminated dri nking water, whereas 114 had not. Time-weighted mean arsenic levels (in mil ligrams per liter) and milligram-years per liter of arsenic exposure were e stimated for each subject. Exposure categories were assessed as <0.5 mg/L, 0.5 to 1.0 mg/L, and >1.0 mg/L and alternatively as <1.0 mg-y/L, 1.0 to 5.0 mg-y/L, >5.0 but less than or equal to 10.0 mg-y/L, and >10.0 mg-y/L, resp ectively. Hypertension was defined as a systolic blood pressure of greater than or equal to 140 mm Hg in combination with a diastolic blood pressure o f greater than or equal to 90 mm Hg. Corresponding to the exposure categori es, and using "unexposed" as the reference, the prevalence ratios for hyper tension adjusted for age, sex, and body mass index were 1.2, 2.2, 2.5 and 0 .8, 1.5, 2.2, 3.0, in relation to arsenic exposure in milligrams per liter and milligram-years per liter, respectively. The indicated dose-response re lationships were significant (P much less than 0.001) for both series of ri sk estimates. These results suggest that arsenic exposure may induce hypert ension in humans.