Dioxin exposure and type 2 diabetes mellitus: Case control study

OBJECTIVES: Relationship between dioxin exposure and diabetes mellitus (DM) has been in debate. Our cross-sectional study suggested that low-level dioxin exposure may cause type 2 diabetes in a general population. A case control study was performed to confirm the risk of dioxins. DESIGN and METHODS: 60 DM patients and 60 controls were selected for the case control study to detect the risk of dioxins for type 2 diabetes mellitus. After performing 75 g GTT, 56 DM, 12 IGT and 49 Control were grouped. In addition to the routine physical examination, questionnaire for life habits, past illness, family history and others were performed. 70 ml blood was collected for hematological and biochemical test, and measurement of 7 polychlorodibenzo-p-dioxins (PCDD), 10 polychloro-dibenzofurans (PCDF), and 12 coplanar polychlorobiphenyl (PCB). Concentration of dioxin congeners and their TEQ were used for regression factor analysis and logistic regression analysis to detect the risk of dioxins by SPSS. RESULTS: Total blood dioxin level was 23.4 ± 11.2 in Control, 30.8 ± 11.5 in IGT and 33.7 ± 13.7 pg TEQ/g lipid in DM. Logistic regression analysis revealed that family history (OR=20.4) and 4 of 5 dioxin factors (OR=2.2-2.8) had significant odds ratio. Crude congener concentration and their TEQ yielded the similar results. Other variables did not show significant odds ratio. Adverse effects of dioxins on TNFalpha, NEFA, adiponectin, and leptin were found. CONCLUSION: DM and IGT patients showed higher dioxin level compared to Control. Logistic regression analysis revealed that the exposure to both PCB and PCDD/PCDF showed significant effect.