Study Links Low Dose POPs Exposure to Type 2 Diabetes

(Beyond Pesticides, September 28, 2010)

A study published in the September 2010 issue of the journal Environmental Health Perspectives links low dose exposure to some persistent organic pollutants (POPs) to type 2 diabetes. The authors report that some POPs, including highly chlorinated PCBs, PBB153 and the organochlorine insecticides trans-nonachlor, oxychlordane and mirex, were associated with type 2 diabetes over an 18-year period, especially in obsese people. However, POPs did not show a traditional dose—response relationship with diabetes. Instead, POPs showed strong associations at relatively low exposures. The authors conclude that exposure to relatively low concentrations of certain POPs may play a role in the increased incidence of diabetes in the United States.

The study, “Low Dose of Some Persistent Organic Pollutants Predicts Type 2 Diabetes: A Nested Case—Control Study,” examines participants who were diabetes free in 1987—1988. By 2005—2006, the 90 controls remained free of diabetes, whereas the 90 cases developed diabetes. Using serum collected in 1987—1988, the authors measured 8 organochlorine pesticides, 22 polychlorinated biphenyl congeners (PCBs), and 1 polybrominated biphenyl (PBB). They compare POP concentrations from Coronary Artery Risk Development in Young Adults (CARDIA) cohort and the National Health and Nutrition Examination Survey (NHANES) in 2003—2004.

Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Because of this, they have been observed to persist in the environment, to be capable of long-range transport, bioaccumulate in human and animal tissue, biomagnify in food chains, and to have potential significant impacts on human health and the environment. Many POPs are currently or were in the past used as pesticides. Others are used in industrial processes and in the production of a range of goods such as solvents, polyvinyl chloride, and pharmaceuticals. The Stockholm Convention on Persistent Organic Pollutants is an international environmental treaty that aims to eliminate or restrict the production and use of persistent organic pollutants (POPs).

While the POPs pesticides implicated in this study are no longer used in the U.S., the study illustrates how the health impacts of pesticides are often subtle and delayed, and how pesticides once considered to pose “acceptable” risks are continuing to affect public health years after being pulled from the market. In response to the growing evidence linking pesticide exposures to numerous human health effects, Beyond Pesticides launched the Pesticide-Induced Diseases Database, to capture the range of diseases linked to pesticides through epidemiologic studies. The database, which currently contains hundreds of entries of epidemiologic and laboratory exposure studies, will be continually updated to track the emerging findings and trends.

To address this issue, Beyond Pesticides has called for alternatives assessment in environmental rulemaking that creates a regulatory trigger to adopt alternatives and drive the market to go green. The alternatives assessment approach differs most dramatically from risk assessment in rejecting uses and exposures deemed acceptable under risk assessment calculations, but unnecessary because of the availability of safer alternatives. For example, in agriculture, where the database shows clear links to pesticide use and multiple types of cancer, it would no longer be possible to use hazardous pesticides, as it is with risk assessment-based policy, when there are clearly effective organic systems with competitive yields that, in fact, outperform chemical-intensive agriculture in drought years. This same analysis can be applied to home and garden use of pesticides where households using pesticides suffer elevated rates of cancer.

For more information, see Beyond Pesticides’ Pesticide-Induced Diseases Database,