Objective: The prevalence of type 2 diabetes is increasing alarmingly in both developed and developing countries. Recently, exposure to persistent organic pollutants (POPs) has been associated with the prevalence of type 2 diabetes. The purpose of this cross-sectional study is to examine the association between type 2 diabetes and POP exposure in the Helsinki Birth Cohort Study.
Research design and methods: The cohort consists of 8,760 people born in Helsinki during 1934-1944, before the global POP emission peak. In 2003, a clinical examination was performed, including blood sampling for laboratory analyses of serum lipids and POPs. Complete data from the examination were available for 1,988 participants. The concentrations of each POP were categorized into four groups on the basis of percentile intervals, and logistic regression was performed to examine diabetes prevalence across the POP categories, adjusting for sex, age, waist circumference, and mean arterial pressure and using the lowest category as the reference group.
Results: Among the participants with the highest exposure to oxychlordane, trans-nonachlor, 1,1-dichloro-2,2-bis-(p-chlorophenyl)-ethylene (p,p'-DDE, and polychlorinated biphenyl 153, the risk of type 2 diabetes was 1.64-2.24 times higher than that among individuals with the lowest exposure (P(lin) = 0.003-0.050, where P(lin) is the P value for linear trend across POP categories). In the stratified analysis, the associations between type 2 diabetes and oxychlordane and trans-nonachlor remained significant and were strongest among the overweight participants. Exposure to 2,2',4,4'-tetrabromodiphenyl ether (BDE 47) and 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE 153) was not associated with type 2 diabetes.
Conclusions: This study confirms the association between type 2 diabetes and adult-only exposure to organochlorine pesticides in a general urban population.