Grant: Travel Awards - Institute Community Support

Although banned in Western countries since the 1970s, DDT insecticide (dichlorodiphenyltrichloroethane) is used in 11 countries for Indoor Residual Spraying (IRS) programs to control mosquitoes that carry malaria. More than 120 million people around the world are exposed to IRS insecticides. Recent studies on humans and animals suggest that DDT could increase the risk of hypertension. However, no study has investigated whether DDT could increase the risk of the hypertensive disorders of pregnancy (HDP), which are a leading cause of maternal morbidity and mortality in most countries where IRS is used. Our aim was to determine whether serum concentrations of DDT and its main breakdown product, DDE, are associated with preeclampsia, blood pressure, and protein in urine among pregnant women. We evaluated 751 mother-infant pairs from South Africa and used data from the National Institute of Environmental Health Sciences-funded Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), a cohort study following mother-infant pairs from birth. Blood samples were taken from all participants at the time of delivery to determine concentrations of DDT and DDE. Data on the diagnosis of HDP (preeclampsia, eclampsia or pregnancy-induced hypertension) was collected using a questionnaire and blood pressure was abstracted from medical records. We found that every 10-fold increase in maternal DDT and DDE concentrations was associated with a 47% and 53% elevated risk of hypertension, preeclampsia or eclampsia, respectively. While elevated concentrations of DDT and DDE were associated with higher blood pressure measurements and protein in urine, these results were not statistically significant. Results therefore suggest that DDT and DDE exposure may increase the risk of HDP. This is the first study investigating this question in an IRS area. Results will contribute to the risk-benefit analysis of DDT use for malaria control by national and international organizations.