Strong associations between low-dose organochlorine pesticides and type 2 diabetes in Korea

Low-dose organochlorine (OC) pesticides have recently been associated with type 2 diabetes in several non-Asian general populations. As there is currently epidemic type 2 diabetes in Asia, we investigated the associations between OC pesticides and type 2 diabetes in Koreans. Among subjects who participated in a community-based health survey, we randomly selected 40 diabetic patients and 40 normal controls. Ten OC pesticides (beta-hexachlorocyclohexane, hexachlorobenzene, heptachlor epoxide, p,p′-DDE, p,p′-DDD, p,p′-DDT, o,p′-DDT, oxychlordane, trans-nonachlor, and mirex) detectable in ≥ 70% of controls were analyzed in relation to diabetes. Most OC pesticides showed strong associations with type 2 diabetes after adjusting for age, sex, BMI, alcohol consumption, and cigarette smoking. Compared with subjects in the lowest tertile of each OC pesticide, adjusted odds ratios (ORs) in the 3rd tertile ranged from 3.1 (95% CI 0.8–12.1) for heptachlor epoxide to 26.0 (95% CI 1.3–517.4) for oxychlordane. In the case of chemicals belonging to the DDT family, adjusted ORs in the 3rd tertile were in the range of 10.6 (95% CI 1.3–84.9) for p,p′-DDT to 12.7 (95% CI 1.9–83.7) for p,p′-DDE. In this exploratory study with small sample, low-dose background exposure to OC pesticides was strongly associated with prevalent type 2 diabetes in Koreans even though absolute concentrations of OC pesticides were no higher than in other populations. Asians may be more susceptible to adverse effects of OC pesticides than other races.