Persistent Organic Pollutants and Type 2 Diabetes: A Prospective Analysis in the Nurses’ Health Study and Meta-analysis

Hongyu Wu,¹ Kimberly A. Bertrand,^2,3 Anna L. Choi,⁴ Frank B. Hu,^1,2,3 Francine Laden,^2,3,4 Philippe Grandjean,^4,5 and Qi Sun^1,3


¹Department of Nutrition, and ²Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA; ³Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA; ⁴Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA; ⁵Institute of Public Health, University of Southern Denmark, Odense, Denmark


Abstract

Background: Prospective data regarding persistent organic pollutants (POPs) and risk of type 2 diabetes (T2D) are limited, and the results for individual POPs are not entirely consistent across studies.


Objectives: We prospectively examined plasma POP concentrations in relation to incident T2D and summarized existing evidence in a meta-analysis.


Methods: Plasma polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), and hexachlorobenzene (HCB) concentrations were measured in 1,095 women who were free of diabetes at blood draw in 1989–1990 and participated in two case–control studies in the Nurses’ Health Study. We identified 48 incident T2D cases through 30 June 2008. We conducted a literature search in PubMed and EMBASE through December 2011 to identify prospective studies on POPs in relation to diabetes. We used a fixed-effects model to summarize results.


Results: After multivariable adjustment, plasma HCB concentration was positively associated with incident T2D [pooled odds ratio (OR) 3.59 (95% CI: 1.49, 8.64, p_trend = 0.003) comparing extreme tertiles]. Other POPs were not significantly associated with diabetes. After pooling our results with those of six published prospective studies that included 842 diabetes cases in total, we found that HCB and total PCBs both were associated with diabetes: the pooled ORs were 2.00 (95% CI: 1.13, 3.53; I² = 21.4%, p_{heterogeneity} = 0.28) and 1.70 (95% CI: 1.28, 2.27; I² = 16.3%, p_{heterogeneity} = 0.30) for HCB and total PCBs, respectively. 


Conclusions: These findings support an association between POP exposure and the risk of T2D.


Key words: DDE, DDT, dichlorodiphenyldichloroethylene, dichlorodiphenyltrichloroethane, HCB, hexachlorobenzene, PCB, persistent organic pollutant, polychlorinated biphenyl, POP, type 2 diabetes. 


Environ Health Perspect 121:153–161 (2013). http://dx.doi.org/10.1289/ehp.1205248 [Online 5 November 2012]


Address correspondence to Q. Sun, Department of Nutrition, Harvard School of Public Health, 665 Huntington Ave., Boston, MA 02115 USA. Telephone: (617) 432-7490. E-mail: qisun@hsph.harvard.edu


Supplemental Material is available online (http://dx.doi.org/10.1289/ehp.1205248).


This work was supported by the National Institutes of Health (grants DK58845, CA87969, CA49449, ES013692, and CA098122). K.A.B. was supported by the Training Program in Environmental Health Sciences (grant T32 ES007155) and the Nutritional Epidemiology of Cancer Education and Career Development Program (R25 CA098566). Q.S. was supported by career development award R00HL098459 from the National Heart, Lung, and Blood Institute and a Pilot and Feasibility Program sponsored by the Boston Obesity Nutrition Research Center (grant DK46200). 


The authors declare they have no actual or potential competing financial interests.


Received 23 March 2012; Accepted 5 November 2012; Online 5 November 2012.