WASHINGTON (AFP) — Even low-level exposure to arsenic in drinking water appears to be associated with increased prevalence of type 2 diabetes, researchers said in a study published Tuesday.

Millions of people across the world consume drinking water containing arsenic from inorganic sources, said the researchers in the August 20 issue of the Journal of the American Medical Association (JAMA).

In the United States, 13 million people drink tap water containing more than the US Environmental Protection Agency standard of 10 micrograms per liter of inorganic arsenic, the study said.

Earlier research established a link between exposure to high levels of inorganic arsenic in the public water supply or in the workplace and type 2, or adult-onset, diabetes, but little was known about the effects of low-level exposure, it said.

Ana Navas-Acien, of the Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, and colleagues studied 788 adults age 20 and older who had their urine tested for arsenic levels as part of a government-conducted 2003-2004 survey.

The researchers found that the 7.7 percent of the participants who had type 2 diabetes, after adjusting for other diabetes risk factors, had a 26 percent higher level of arsenic in their urine than those without the disease.

The study also found that 20 percent of the participants who had the highest arsenic levels in their urine (16.5 micrograms per liter) had 3.6 times higher risk of having type 2 diabetes than the 20 percent with the lowest level (3.0 micrograms per liter).

They concluded that arsenic could influence genetic factors that interfere with insulin sensitivity and other processes, or could contribute to oxygen-related cell damage, inflammation and cell death, which have also been related to diabetes.

“Given widespread exposure to inorganic arsenic from drinking water worldwide, elucidating the contribution of arsenic to the diabetes epidemic is a public health research priority with potential implications for the prevention and control of diabetes,” the researchers said.

Odorless, colorless, tasteless and easily dissolved in water, arsenic is extremely poisonous at high levels.

Aug. 19, 2008 — Exposure to arsenic, typically through drinking water, is linked to diabetes, according a study published in the Journal of the American Medical Association.

Thirteen million Americans — and millions more worldwide — are exposed to drinking water contaminated with more inorganic arsenic than the Environmental Protection Agency has deemed safe. The EPA standard is 10 micrograms per liter.

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Researchers, led by Ana Navas-Acien, MD, PhD, of the Johns Hopkins Bloomberg School of Health, studied 788 adults who had their urine tested for arsenic exposure in the 2003-2004 National Health and Nutrition Examination Survey. Participants with type 2 diabetes had a 26% higher level of total arsenic in their urine than those without the disease. Levels of organic arsenic, called arsenobetaine, which is often found in seafood, were similar between two groups. Arsenobetaine is considered nontoxic.

After adjusting for diabetes risk factors and seafood intake, researchers found that participants in the top one-fifth of total urine arsenic levels (16.5 micrograms per liter) had 3.6 times the odds of having type 2 diabetes as those in the lowest one-fifth (3 micrograms per liter).

Researchers also looked at levels of dimethylarsinate, a compound created when inorganic arsenic is metabolized before excretion. Participants in the top one-fifth of urine dimethylarsinate levels (6 micrograms per liter) had 1.6 times the odds of having type 2 diabetes as those in the lowest one-fifth (2 micrograms per liter.)

There are several reasons that inorganic arsenic may contribute to diabetes. Insulin-sensitive cells that are exposed to insulin and sodium arsenic appear to take in less glucose than cells exposed only to insulin. Arsenic could influence genetic factors that interfere with insulin sensitivity and other processes. Arsenic also may contribute to oxygen-related cell damage, inflammation, and cell death, all of which are linked to diabetes.

The study adds more evidence that inorganic arsenic in drinking water is dangerous. Previous research has linked arsenic to cancer and other health problems.

“Given widespread exposure to inorganic arsenic from drinking water worldwide, elucidating the contribution of arsenic to the diabetes epidemic is a public health research priority with potential implications for the prevention and control of diabetes,” the authors conclude.

An accompanying editorial written by Molly L. Kile, ScD, and David Christiani, MD, MPH, both of the Harvard School of Health, highlights the increasing prevalence of type 2 diabetes, which affects 7.8% of Americans (24 million individuals). Most research focus has been on prevention through medication and lifestyle changes, but additional research needs to be done on environmental factors, the authors write.

In the meantime, Kile and Christiani write, “It is prudent to minimize arsenic exposures while its effect on metabolic diseases continues to be researched.”