1 in 5 deaths in Bangladesh linked to arsenic in drinking water

Exposure to arsenic in drinking water - even at low levels - increases the risk of death from any cause, suggests a new study conducted on Bangladeshis.

Arsenic is known to be a potent carcinogen and toxic to organs such as the liver, skin, kidney and the cardiovascular system.

But previous studies assessing the effects of long-term drinking-water exposure to arsenic have lacked resolution, relying upon retrospective analysis and estimations of exposure on a group, rather than individual, level.

In a new study of 12,000 Bangladeshis, more than 20% of deaths were attributable to arsenic exposure from contaminated drinking water.

The large 10-year study is the first to prospectively measure the relationship between individual exposure to arsenic and its associated mortality risk, the authors said.

The data was collected by an international team from Chicago, New York, and Bangladesh

Since the widespread installation of hand-pumped wells to tap groundwater sources in the 1970's, as many as 77 million people - about half the population of Bangladesh - have been accidentally exposed to dangerous levels of arsenic.

The World Health Organisation calls the exposure "the largest mass poisoning of a population in history."

The Health Effects of Arsenic Longitudinal Study (HEALS) was led by Habibul Ahsan, MD, MMedSc, Director of the Center for Cancer Epidemiology and Prevention at the University of Chicago Medical Center.

Arsenic levels from well drinking-water and repeated biennial urine samples of 12,000 subjects were associated with deaths in that population over the last decade.

For the 25% of people exposed to the highest levels of arsenic, mortality risk increased by nearly 70%, the study determined.

People exposed to moderate levels of the poisonous chemical also exhibited increased deaths from chronic disease, relative to those whose exposure was within WHO recommendations of 10 parts per million.

The authors said: "The results of this study have important public health implications for arsenic in drinking water. The exposure levels studied are similar to other populations that have low-level arsenic exposure."

The study has been published early online Saturday in The Lancet.