Arsenic exposure may trigger hypertension

By Helen Albert, Senior medwireNews Reporter

Results from a Chinese study suggest that exposure to arsenic through contaminated drinking water may increase a person's risk for developing hypertension.

"Although some studies mainly from Taiwan, Bangladesh and the United States, have suggested a consistent dose-response increase in the prevalence of hypertension with increasing arsenic exposure, the association between chronic environmental arsenic exposure and the risk of hypertension is still inconclusive," write Guifan Sun (China Medical University, Shenyang, Liaoning Province) and colleagues.

They recruited 604 people (255 men; mean age 52 years) living in an area contaminated with arsenic in the northwest of China to take part in the study, of whom 168 had hypertension.

The team estimated cumulative arsenic exposure (CAE) in 360 individuals with a detailed water consumption record by testing first void urine for the presence of inorganic arsenic (iAs), monomethylated arsenic (MMA), dimethylated arsenic (DMA), and total arsenic.

As reported in Environmental Health, Sun and team found a direct positive correlation between the four urinary arsenic measures and systolic or pulse blood pressure, although not diastolic blood pressure. People in the highest tertile for CAE also had a significantly increased risk for hypertension compared with those in the lowest tertile.

Regarding specific arsenicals, people in the highest tertile for MMA had a 1.69-fold higher risk for hypertension than those in the lowest tertile after adjustment for confounders. Similarly, those in the highest versus the lowest tertile for urinary DMA and iAs had an increased risk for hypertension, although this became nonsignificant following adjustment for confounders.

"Taken together, our findings suggested that arsenic exposure, especially high level of CAE, waspositively associated with the prevalence of hypertension, and that higher concentration of urinary MMA might be related to the increased susceptibility to hypertension," write the researchers.

"Further studies are needed to evaluate the effects of low level arsenic exposure from drinking water on hypertension, and the association in some special aspects such as nutritional deficiencies and gene polymorphisms," they conclude.

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