Background:
Animal experiments have suggested that exposure to persistent organic pollutants (POPs) may lead to increased risk of type 2 diabetes. Although recent human studies supported this hypothesis, evidence from prospective investigations is sparse.
Objective:
To examine the associations of plasma POP concentrations with risk of incident type 2 diabetes in a prospective setting among US women.
Methods:
Study population was comprised of participants from two independent nested case-control studies in the Nurses’ Health Study, in which major polychlorinated biphenyl (PCB 118, 138, 153, and 180), p-p'- dichlorodiphenyldichloroethylene (DDE), dichlorodiphenyltrichloroethane (DDT), and hexachlorobenzene (HCB) were measured. A non-parametric approach was used to derive standardized scores for plasma concentrations of lipid-adjusted POPs within each study to minimize between-study variation of the POP measurements. Risk of incident type 2 diabetes during the follow-up period (1990-2008) across the tertiles of the scores was examined.
Results:
Of 1,120 participants, we identified 48 incident type 2 diabetes cases. After adjusting for covariates assessed at blood draw in 1990, including smoking status, body mass index, and total fish intake, plasma HCB concentration was positively associated with type 2 diabetes risk: odds ratio (OR) (95% confidence interval [CI]) was 2.77 (1.17, 6.55,
P
for trend =0.022) comparing the highest vs. lowest tertile. Other POPs were not significantly associated with diabetes: the ORs (95% CI) were 1.10 (0.51, 2.34,
P
for trend =0.81) for p-p'-DDE, 0.93 (0.44, 1.95,
P
for trend =0.86) for DDT, and 0.88 (0.39, 1.97,
P
for trend =0.76) for sum of the 4 major PCBs, comparing the extreme tertiles.
Conclusion:
The significant association of plasma HCB concentration with diabetes risk supports a role of POP exposure in the etiology of type 2 diabetes. More prospective data are warranted to confirm these findings.
Soft Drink and Juice Consumption and Risk of Physician-diagnosed Incident Type 2 Diabetes: The Singapore Chinese Health Study
