Impaired Semen Quality Associated With Environmental DDT Exposure in Young Men Living in a Malaria Area in the Limpopo Province, South Africa

Abstract

The pesticide DDT [1,1,1-trichloro-2,2-bis(chlorodiphenyl)ethane] is 1 of the 12 persistent organic pollutants (POPs) under negotiation at the Stockholm Convention to restrict or ban their production and use because of their toxicity, resistance to breakdown, bioaccumulation, and potential for being transported over long distances. DDT has estrogenic potential, and the main metabolite, p,p9-dichlorodiphenyl-dichloroethylene (p,p9-DDE), is a potent antiandrogen. In response to mounting evidence on the endocrine-disrupting influence of environmental chemicals on human health, this epidemiological study was initiated to test the hypothesis that nonoccupational exposure to DDT affects male reproductive parameters. In a cross-sectional study, healthy male subjects (n 5 311) between 18 and 40 years (23 6 5) of age were recruited from 3 communities in an endemic malaria area in which DDT is sprayed annually. A semen analysis according to World Health Organization (WHO) standards was performed. The Hamilton Thorne Computer Assisted Sperm Analysis (CASA) system was simultaneously used to determine additional sperm motility parameters. Blood plasma samples were assayed for p,p9-DDT and metabolites as a measure of exposure. The exposure levels were expressed as lipid-adjusted p,p9-DDT and p,p9-DDE values. The mean p,p9-DDT and p,p9-DDE concentrations were 90.23 mg/g (6102.4) and 215.47 mg/g (6210.6), respectively. The multivariate linear regression analyses indicated that mean CASA motility was lower with a higher p,p9-DDE concentration (b 5 20.02, P 5 .001) and the CASA parameter beat cross-frequency (BCF) was higher with a higher p,p9-DDT concentration (b 5 0.01, P 5 .000). There was also a statistically significant positive association between percent sperm with cytoplasmic droplets and p,p9-DDT concentration (b 5 0.0014, P 5 .014). The ejaculate volume (mean 1.9 6 1.33 mL) was lower than the normal range ($2.0 mL) according to WHO, and a significant decrease with increasing p,p9-DDE values was seen for both square roottransformed volume (b 5 20.0003; P 5 .024) and count (b 5 20.003; P 5 .04). Although there were no associations between either p,p9-DDT or p,p9-DDE concentrations and the rest of the seminal parameters, the incidence of teratozoospermia (99%; normal sperm ,15%) was high. Twenty-eight percent of the study group presented with oligozoospermia (,20 6 10 6 sperm/mL), which had a significant positive association with p,p9-DDE (odds ratio [OR] 5 1.001, P 5 .03). There was a significant positive association between participants with asthenozoospermia (32%) and p,p9-DDT (OR 1.003, P 5 .006) and p,p9-DDE (OR 1.001, P 5 .02). The results imply that nonoccupational exposure to DDT is associated with impaired seminal parameters in men. The high exposure levels of p,p9-DDT and p,p9-DDE are of concern because these levels could have far-reaching implications for reproductive and general health.

DDT contamination from indoor residual spraying for malaria control

“…p,p′-DDT, an estrogenic endocrine disrupting chemical, and its anti-androgenic metabolite, p,p′-DDE, have been linked to male reproductive health effects Aneck-Hahn et al, 2006). DDT and/or DDE have also been linked with post generational female reproductive ability (Cohn et al, 2003), urogenital birth defects in neonates (Bornman et al, 2005) and pre-term births (Longnecker et al, 2001).…”

“…Although some studies have found little evidence for a link between DDT exposure and health effects, (Cocco et al, 2005(Cocco et al, , 2006, other studies have shown that DDT and its metabolites may have adverse health effects in humans (e.g. Beard, 2006;IPEP, 2006;Aneck-Hahn et al, 2006;Eskenazi et al, 2009). However, limited data is available on the levels of DDT exposure experienced by those living in sprayed homes.…”

Estimation of human body concentrations of DDT from indoor residual spraying for malaria control

“…Recent studies from South Africa found reduced retinol-binding protein and thyroid hormone concentration, urogenital malformations in newborn boys, and impaired semen quality, associated with non-occupational exposure to DDT (Aneck-Hahn et al, 2007;Bornman et al, 2010;Delport et al, 2011).…”

Implications for health education and intervention strategies arising from children's caregivers concerns following successful malaria control

“…[17][18][19] Therefore, one should be aware of the possibility that the lack of community involvement in an existing community-passive malaria control system may also become a problem when promoting measures to reduce exposure to IRS chemicals 27 , as some of these are likely to involve behavioural changes.…”

“…Formal employment opportunities are few, and many are subsistence farmers. [16][17][18] Based on aerial photographs, random starting points for systematic homestead sampling were identified. Because the villages are informally planned and homesteads are often without clear site boundaries, it was impossible to derive a precise number of homesteads for each village.…”