Eat right and exercise, conventional wisdom has it, if you want to avoid joining the diabetes epidemic.

But a new study adds some muscle to a growing body of research suggesting those steps, though beneficial, might not be enough for people exposed to chemicals in the environment.

The scientists linked diabetes and people’s body burdens of DDE, a chemical produced as the body breaks down the pesticide DDT, banned in the United States more than 35 years ago.

“Even though we haven’t used DDT in decades, its metabolites are still detected in almost everyone in the country,” said lead researcher Mary Turyk, an epidemiologist at the University of Illinois-Chicago’s School of Public Health.

Since the early 1990s, researchers have monitored a group of Great Lakes charter boat captains, recreational fishermen and others to learn about the health effects of eating fish tainted with persistent organic pollutants – chemicals that remain in the environment for decades and grow more concentrated as they move up food chains.

For the new study, blood samples from the Great Lakes group showed “consistent, dose-related associations of DDE” with diabetes, the researchers wrote in the July issue of Environmental Health Perspectives.

Among 471 adults, including 36 with diabetes, there was no link to the disease based on the amount of fish consumed or exposure to other pollutants. But the higher the concentration of DDE in the blood, the more likely they were to develop diabetes.

The study is among the strongest voices in a chorus of research supporting the link between environmental chemicals and diabetes, according to David O. Carpenter, director of the Institute for Health and the Environment at the University of Albany in New York. He was not involved in the study.

“Most people have not thought of diabetes as a disease related to environmental exposure,” he said, “and these studies show that it is. The science has been growing very, very rapidly, and to my mind, it’s one of the most exciting developments in the study of diabetes.”

Diabetics cannot produce or use enough insulin, a hormone that lets glucose – the body’s fuel – enter cells. More than 23 million Americans, or eight percent of the population, are diabetic, and that group swelled by 13.5 percent from 2005 to 2007, according to the American Diabetes Assn.

For the most common type of diabetes, Type 2, obesity and lack of exercise play a key role. The bulk of studies searching for a cause have focused on lifestyle factors, while research on environmental influences hasn’t been prominent in journals devoted to the disease, said Henry Kahn, an epidemiologist with the Centers for Disease Control and Prevention’s Division of Diabetes Translation.

“But maybe it should be. It would be foolish to overlook pollution as a factor,” he said, adding that he and colleagues have lately taken a greater interest in the role of pollutants. “We recognize it’s possibly a very important thing,” he said. “We agree it’s on the list of things worth studying.”

Oliver Jones, a biochemist at the University of Cambridge, wrote in the journal Lancet last year that “if there is indeed a link” between contaminants and diabetes, “the health implications could be tremendous. There has been almost no consideration for the possible influence of environmental factors such as pollution."

6 Comments

1. 1. jonderry 05:18 PM 7/20/09

   It may be that theyre toxic to the pancreas, which produces insulin Kahn added. We dont know.
   
   Why not test for a correlation between DDE and insulin resistance, which is usually the first step toward adult-onset type 2 diabetes? This would be an easy way to figure out if DDE is hurting pancreas function or if it's more of a glucose receptor issue.

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2. 2. met in reply to jonderry 10:33 PM 7/20/09

   Data on insulin resistance was not available for the Great Lakes charter boat captains. Insulin resistance in non-diabetics was examined in the large CDC study, called NHANES, mentioned in the story (Lee et al, Diabetes 30:628, 2007). These authors found that insulin resistance was associated with organochlorine pesticides, but not PCBs or dioxins.

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3. 3. RobLL 06:21 PM 7/21/09

   It is perhaps more likely that insulin resistance and other factors preceding a diagnosis of diabetes may cause abdominal obesity than the other way around.

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4. 4. Quinn the Eskimo 02:27 AM 7/23/09

   The primary disability of the Veterans from Northeast Cape, Alaska is Diabetes and Heart Failure. NE Cape is a Super Fund Site and heavily polluted with PCB's.
   
   Of the 2,500 or so vets, diabetes is endemic. Cancer and heart attacks are common.
   
   But, the Russians never took the station! (not that they ever wanted it).

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5. 5. carpent in reply to Quinn the Eskimo 05:38 PM 7/24/09

   I've just returned from St. Lawrence Island where we are studying diseases in the Siberian Yupiks who live there. They have extremely elevated levels of PCBs, and those families with hunting camps at the Northeast Cape have higher levels than those that do not. PCBs cause diabetes and heart disease. Where can I find the evidence for these diseases are elevated in Veterans who worked there?

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6. 6. sarhow 07:53 AM 4/13/10

   I've made a website summarizing the studies on contaminants and diabetes: www.diabetesandcontaminants.org. It focuses on type 1, but I also included studies on type 2 and gestational diabetes, since there is overlap among these diseases. And, I included studies on contaminants and insulin resistance, metabolic syndrome, and other pre-diabetes conditions.

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