Predictors of Plasma DDT and DDE Concentrations among Women Exposed to Indoor Residual Spraying for Malaria Control in the South African Study of Women and Babies (SOWB)

Abstract

Background: Few studies have examined predictors of DDT (dichlorodiphenyltrichloroethane) and DDE (dichlorodiphenyldichloroethylene) levels among residents in homes sprayed with DDT for malaria control with the aim of identifying exposure-reduction strategies.Methods: The present analysis included 381 women enrolled in the Study of Women and Babies (SOWB) during 2010–2011, from eight South African villages in the Limpopo Province, South Africa. Indoor residual spraying (IRS) occurred in half of the villages. Questionnaires regarding various demographic and medical factors were administered and blood samples were obtained. We classified the women into three exposure groups by type of residence: unsprayed village (n = 175), IRS village in household with a low likelihood of DDT use (non-DDT IRS household, n = 106), IRS village in household with a high likelihood of DDT use (DDT IRS household, n = 100). We used multivariable models of natural log-transformed DDT plasma levels (in micrograms per liter) and DDE (in micrograms per liter) to identify predictors for each group.Results: Median levels of DDT and DDE among women in unsprayed villages were 0.3 [interquartile range (IQR): 0.1–0.9] and 1.7 (IQR: 0.7–5.5), respectively. Median levels of DDT and DDE among women in DDT IRS households were 2.6 (IQR: 1.1–6.6) and 8.5 (IQR: 4.7–18.0), respectively. In unsprayed villages, women with water piped to the yard, rather than a public tap, had 73% lower DDT (95% CI: –83, –57%) and 61% lower DDE (95% CI: –74, –40%) levels. In DDT IRS households, women who reported taking more than six actions to prepare their home before IRS (e.g., covering water and food) had 40% lower DDT levels (95% CI: –63, –0.3%) than women who took fewer than four actions.Conclusion: The predictors of DDT and DDE plasma levels identified in the present study may inform interventions aimed at decreasing exposure. Among households where DDT is likely to be used for IRS, education regarding home preparations may provide an interventional target.Citation: Whitworth KW, Bornman RM, Archer JI, Kudumu MO, Travlos GS, Wilson RE, Longnecker MP. 2014. Predictors of plasma DDT and DDE concentrations among women exposed to indoor residual spraying for malaria control in the South African Study of Women and Babies (SOWB). Environ Health Perspect 122:545–552; http://dx.doi.org/10.1289/ehp.1307025

DDT Exposure in Utero and Breast Cancer

“…Thus, the findings of this study are relevant to current populations in which high in utero exposure is certainly occurring, such as in South Africa (23). The impact of DDT use on unborn generations has been recently raised as an ethical consideration (41).…”

“…Third, because of its persistent presence in the environment, people worldwide continue to be exposed to DDTs that are already present (17). Environmental contamination and human exposure are greater where use was recent and where safer use, storage, and disposal are challenging (18), such as in China (19) and areas in Mexico (20,21) and Africa (22,23). Indeed, DDT health effects will remain relevant for the foreseeable future, given that the distribution of malaria vectors is predicted to expand with climate change (24).…”

DDT exposure of frogs: A case study from Limpopo Province, South Africa

“…The reason why there is so little p,p'-DDT in aquatic biota in areas where there is active application of this compound is not known. This could be due to the tropical nature of the area and that initial application is done as indoor residual spray (IRS) Whitworth et al 2014). The residues Ptychadena anchietae Zimbabwe Farming area using DDT Whole animal <1989 1 300-1 500 from malaria control probably travel a longer route before reaching the aquatic environment than agriculturally applied DDT and therefore more p,p"-DDT will break down to p,p"-DDE.…”

“…From decades of use, residues of DDT associated with malaria control have accumulated in the environment and in human and animal tissues. DDT residues have been measured in human milk (Bouwman et al 1990, Bouwman et al 2006, Sereda et al 2009) and blood (Aneck-Hahn et al, 2007, Whitworth et al, 2014Gaspar et al 2015) from inhabitants to the east of Thohoyandou, Vhembe District, Limpopo Province ( Fig. 1).…”

Anti-Müllerian Hormone and Lifestyle, Reproductive, and Environmental Factors Among Women in Rural South Africa

“…The specific analytic methods, including quality assurance/quality control (QA/QC) are described elsewhere. 19 Briefly, DDT and DDE specimens were analyzed in 14 batches, thirteen of which contained an aliquot from a single QA/QC specimen. The between-batch coefficient of variation for DDT was 5.0% and for DDE was 7.8%.…”