Pesticide Exposure Ups Diabetes RiskMay 28, 2008 | Parker Waichman LLP
National Institutes of Health (NIH) Researchers in the United States are reporting that certain chlorinated pesticides put a school worker in South Africa at increased risk of developing type 2 diabetes. The researchers also report that the greater the exposure, the greater the risk.
A compound containing the organoclorine lindane was used to fumigate a building on school property in Groblersdal in the Limpopo province of South Africa. In humans, lindane primarily affects the nervous system, liver, and kidneys, and may be a carcinogen and/or endocrine disruptor. The occupational therapist working there was diagnosed with organochlorine poisoning; students also complained of symptoms. The link to type 2 diabetes had not been previously explored in South Africa.
The World Health Organization (WHO) classifies lindane as "Moderately Hazardous," and its international trade is restricted and regulated under the Rotterdam Convention on Prior Informed Consent. The chemical is banned in over 50 countries and is currently under consideration for inclusion in the Stockholm Convention on persistent organic pollutants, which would ban its production and use worldwide.
Dr. Johan Minnaar, who treated the patient, reported that a registered pest control company administered the pesticide. "It is shocking how little knowledge people, and especially registered professionals, have on the dangers of pesticides and agricultural chemicals.” Minnaar added, "In South Africa a campaign to create awareness of the dangers of agricultural chemicals is desperately needed."
Meanwhile, researchers at the NIH in the US studied over 31,000 licensed pesticide applicators participating in an Agricultural Health Study. The researchers note that such licensed pesticide applicators use more potent formulations of the chemicals involved in the study than are found in products sold for use in the home or garden. Five years after enrolling in the study, 1,176 of these pesticide applicators developed type 2 diabetes. Among the 50 different pesticides the researchers reviewed, half were chlorinated and seven of these were linked to increased risk of type 2 diabetes. The pesticides are: Aldrin, chlordane, heptachlor, dichlorvos, trichlorfon, alachlor, and cyanazine. Like the pesticide that injured the South African worker and children, “all of the seven pesticides” linked to increased type 2 diabetes are “chlorinated compounds," study investigator Dr. Freya Kamel of the National Institute of Environmental Health in Research Triangle Park, North Carolina said. "We don't know yet what the
implication of that is, but it can't be a coincidence. I think it's an important clue for future research."
The research indicated that risk was higher among study participants who had ever been exposed to any of these chemicals and risk increased as cumulative days of lifetime exposure increased, according to the research team’s report in the American Journal of Epidemiology. The strongest link between exposure to the seven chemicals and type 2 diabetes was seen among obese people. The researchers say this possibly occurred because people with more body fat may store more of the chemicals in their bodies.
The three organochlorine pesticides—aldrin, chlordane, and heptachlor—are no longer sold in the US, Kamel added, but because they accumulate in animal tissues they remain at detectable levels in individuals' bodies, as well as in some food products.