Upstate News

May 20, 2008
Doretta Royer 315 464-4833

SUNY Upstate Medical University collaborates on national study linking PCBs and diabetes

SYRACUSE, N.Y. — High levels of PCBs (polychlorinated biphenyls) may be the newest risk factor for diabetes in men and women between the ages of 35 to 54 regardless of race, obesity, family history of diabetes, or gender, according to preliminary findings of a national study co-led by SUNY Upstate Medical University researchers Allen Silverstone, Ph.D., Ruth Weinstock, M.D., Ph.D., and Paula Rosenbaum, Ph.D.

The findings also support the importance of regular diabetes screening for people in this population. Diabetes is a major risk factor for heart disease and stroke and eye, kidney and nerve damage, but these complications can be prevented or forestalled with proper care.

The SUNY Upstate researchers have been members of the Anniston Environmental Health Research Consortium, charged with conducting the largest PCB health impact study on a highly exposed community in the United States—The Anniston Study.

The Anniston Study began in 2003 and is comprised of five separate investigations evaluating the effects of PCB and its link to diabetes, heart disease and neurocognitive/neurobehavioral behavior. The multi-million dollar Anniston Study is funded by the Agency for Toxic Substances and Disease Registry (ATSDR) of the U.S. Department of Health and Human Services and the Centers for Disease Control.

Silverstone and other consortium members presented their findings April 1 at a town meeting in Anniston, Ala. Findings from other consortium studies showed a link between lower IQ scores in children whose parents were exposed to PCBs. Silverstone, Weinstock and Rosenbaum are preparing for publication three major papers on their findings.

According to Silverstone, who has been affiliated with the study since it began in 2003, SUNY Upstate co-led the Anniston Diabetes Study to evaluate a possible link between PCB exposure and the development of diabetes, metabolic syndrome and immune abnormalities.

“Residents of Anniston, Alabama, were selected for the study as this community is the site where, from the early 1929 to the early 1970s, PCBs were manufactured and where high levels of PCBs still exist in the environment,” said Silverstone, professor of microbiology and immunology and principal investigator of SUNY Upstate’s section of the study.

“Our findings indicate that levels of PCBs higher than the U.S. average were associated with a two- to four-fold greater prevalence of diabetes in Anniston men and women between the ages of 35 to 54 regardless of obesity, family history, gender, or race.”

The SUNY Upstate team worked in collaboration with investigators from the Syracuse VA Medical Center (Weinstock was the only Syracuse VA collaborator), SUNY Buffalo, the University of California, the University of Alabama in Birmingham, Emory and the Jacksonville State University School of Nursing in Alabama. Together they conducted a standardized health survey and performed clinical and laboratory tests on randomly selected households and individuals in Anniston.

“Of the 1,110 study participants who completed an administered health survey, 774 agreed to visit the study project office in Anniston to provide serum samples and physical measurements for clinical and research evaluations and measurements of PCBs,” said Silverstone.

The SUNY Upstate team developed a substantial part of the health evaluation questionnaire and protocols for office visits. The questionnaires, coding of data and notification to participants were administered through the University of Alabama, Birmingham.

Serum samples provided by 774 of the study participants and stored in SUNY Upstate’s Serum and Cellular Bank were tested for insulin and autoantibodies associated with diabetes. Silverstone said that the serum samples are being tested now for thyroid and DNA autoantibodies. Further tests are planned depending on funding.

Local clinical laboratories tested blood samples for glucose and lipids, and the CDC laboratories tested the serum samples for PCBs as well as lipid levels. The serums were coded to each participant’s health questionnaire and the levels of PCB compounds.

People of ages 20 to 93 were included in the study. Those with pre-diabetes were excluded from the statistical risk analyses and separate analyses also were performed for younger and older people to identify groups who might be at higher risk. The statistics used for analysis of the data were adjusted for known risk factors of diabetes such as age and family history of diabetes. The statistical analysis of the data was done primarily by Rosenbaum, in collaboration with CDC statisticians and Scott Bartell, Ph.D., of the University of California—Irvine, who was the overall principal investigator of the study.

“In the analysis with all participants included, we did not see an effect of PCBs on diabetes after accounting for obesity, age, family history of diabetes and other risk factors,” said Silverstone. “However, in the 35 to 54 year olds, even accounting for all the other risk factors, higher PCBs were found to be associated with having diabetes. Given the serious consequences of diabetes and the presence of high levels of PCBs, we are suggesting that all residents of Anniston take advantage of all methods to reduce their risk of diabetes and to detect and treat diabetes as aggressively as possible,” he said.

Silverstone added that the Anniston residents were also at high risk for heart disease and stroke, obesity, high blood pressure and abnormal levels of fats or lipids in the blood.

According to the U.S. Environmental Protection Agency, PCBs are a group of chemicals that contain 209 individual compounds known as congeners with varying harmful effects. While they are no longer produced or used in the United States, the major source of exposure to PCBs today is the redistribution of PCBs already present in soil, water and the food chain. Before 1974 PCBs were used in capacitors, transformers, plasticizers, surface coatings, inks, adhesives, pesticide extenders, and carbonless duplicating paper. After 1974 use of PCBs was restricted to the production of capacitors and transformers. After 1979 PCBs were no longer used in the production of capacitors and transformers. PCBs are a major contaminant in the Hudson River.

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