August 20, 2008
Adult Diabetes Linked To Arsenic
What's flowing in ground water could cause adult-onset diabetes, according to U.S. researchers.
Arsenic is a naturally occurring poison and carcinogen found in ground water. It's odorless, tasteless, colorless, and easily soluble in water or wine.
They studied 788 adults' medical tests and found a nearly fourfold increase in the risk of diabetes in people with low arsenic concentrations in their urine compared to people with even lower levels.
Dr. Ana Navas-Acien and colleagues at Johns Hopkins University in Baltimore found a "relatively strong" association between commonly found levels of arsenic in urine and type 2 diabetes in a study of American adults.
"It seems there is may be no safe level of arsenic," said Navas-Acien.
"Worldwide it's a huge problem," she said. "As water becomes a scarce resource, we need additional sources."
Previous research outside the United States has linked high levels of arsenic in drinking water with diabetes. But, it's the link at low levels that's new.
The research appears in Wednesday's Journal of the American Medical Association.
"The good news is, this is preventable," said Navas-Acien.
New safe drinking water standards may be needed if the findings are duplicated in future studies.
Arsenic can pollute drinking water naturally when minerals dissolve. It is also a byproduct of coal burning and copper smelting.
Utilities use filtration systems to get it out of drinking water.
Seafood also contains nontoxic organic arsenic. The researchers adjusted their analysis for signs of seafood intake and found that people with Type 2 diabetes had 26 percent higher inorganic arsenic levels than people without Type 2 diabetes.
The implications of the new findings are unclear, said Molly Kile, an environmental health research scientist at the Harvard School of Public Health. She wrote an accompanying editorial in the journal.
"Urinary arsenic reflects exposures from all routes - air, water and food - which makes it difficult to track the actual source of arsenic exposure let alone use the results from this study to establish drinking water standards," Kile said.
Kile said the research presents a chicken-and-egg problem; since it's unknown whether diabetes changes the way people metabolize arsenic.
Arsenic can accumulate in the body, and eventually ruin the body's ability to use insulin and convert blood sugar into energy.
Insulin normally fits into cells via molecular doorways called receptors, which in turn signal the cell to move glucose inside. However, arsenic enters the cell and somehow blocks the activity.
Because of known cancer risks, the United States lowered arsenic standards for public water systems to 10 parts per billion in 2001.
In 2006, compliance was required after the study data were collected in 2003 and 2004.
Navas-Acien said it is difficult to discern the difference between the harmful and benign forms of arsenic, though recent laboratory tests allow researchers to detect trace amounts that may pose risks to health.
On the Net:
- Johns Hopkins University
- Journal of the American Medical Association
- Harvard School of Public Health