Organic Pollutant Exposure May Raise Gestational Diabetes Risk

Increased exposure to organic pollutants in early pregnancy may significantly raise a woman’s risk for developing gestational diabetes, according to new research presented at EASD 2015, the annual meeting of the European Association for the Study of Diabetes.

“Our findings support our primary hypothesis that early life exposure to environmental chemicals that act as endocrine disruptors may exacerbate glucose homeostasis disorders such as gestational diabetes,” said study investigator Leda Chatzi, MD, PhD, who is an assistant professor of nutritional epidemiology at the University of Crete, Greece.

Persistent organic pollutants are a group of diverse substances, including polychlorinated biphenyls (PCBs) and organochlorine pesticides, that are resistant to biodegradation. Persistent organic pollutants are present almost everywhere in the environment.

Exposure to endocrine-disrupting chemicals such as persistent organic pollutants has been linked to type 2 diabetes and metabolic disturbances in epidemiological and animal studies. However, little is known about exposure to persistent organic pollutants during pregnancy and the development of gestational diabetes.

Dichlorodiphenyl dichloroethene (DDE-a breakdown product of DDT) and hexachlorobenzene (HCB) are synthetic chemicals that were used widely as pesticides, while PCBs were used in many industrial processes. These chemicals have been banned for decades but remain in the environment where they bioaccumulate in the bodies of animals and humans.

The purpose of this study was to determine the extent to which exposure to current low levels of different persistent organic pollutants in the first trimester of pregnancy is associated with gestational diabetes risk in 639 women from the Rhea pregnancy cohort in Crete, Greece.

The study is the Mother-Child Cohort in Crete, “Rhea” cohort which prospectively examines a population-based sample of pregnant women and their children.

Women who became pregnant during a period of 1 year starting in February 2007 were contacted and asked to participate in the study. The first contact was made at the time of the first comprehensive ultrasound, and several contacts followed during the pregnancy and thereafter.

The researchers determined the concentrations of several PCBs, DDE and HCB in first trimester maternal serum by mass spectrometry. Pregnant women were screened for gestational diabetes between 24 and 28 weeks of gestation.

A total of 68 (7%) women had gestational diabetes. The researchers found that a 10-fold increase in total PCBs was associated with a 4.4 times increased risk for gestational diabetes after adjusting for pre-pregnancy BMI and several other confounders.

The association was similar for no dioxin-like PCBs (4.4 times increased risk). However prenatal DDE and HCB exposure were not significantly associated with gestational diabetes risk.

“[Gestational diabetes] has adverse effects on both the mother and the developing fetus. [Gestational diabetes] has been associated with the development of type 2 diabetes and long-term risks of cardiovascular diseases. Moreover, in children, [gestational diabetes] has been associated with both perinatal and long-term adverse health outcomes,” Chatzi said.

Chatzi and colleagues believe that further studies are warranted to replicate these results and to evaluate potential biological mechanisms underlying the observed associations.

This is an important public health issue that needs to be addressed, they noted, and environmental risk factors for gestational diabetes need to be identified and avoided. Additionally, they emphasized the fact that prevention efforts urgently need to be investigated.

“Exposure to endocrine-disrupting chemicals such as [persistent organic pollutants] is one of the modifiable risk factors contributing to insulin resistance. Pregnant women with gestational diabetes may be more prone to suffer the diabetogenic effect of these pollutants. Thus, it is important to develop preventive interventions in pregnancy, including dietary and lifestyle changes to minimize early life exposure to [persistent organic pollutants],” Chatzi told Endocrinology Advisor.

The researchers now plan to use this cohort to examine whether prenatal exposure to organic pollutants is associated with alterations in glucose metabolism and diabetes development of the offspring in early childhood.

Reference

1. Chatzi L et al. Abstract 318: Exposure to persistent organic pollutants in early pregnancy and risk of gestational diabetes mellitus. Presented at: EASD 2015; Sept. 14-18, 2015; Stockholm.