DDT Levels and Seminal Parameters in Men: The Adverse Impact of Indoor Residual Spraying (IRS)

Abstract

ISEE-371 Objective: To determine DDT exposure levels and seminal parameters in young rural men from Limpopo Province, South Africa, where indoor residual spraying (IRS) is done annually for malaria vector control. Material and Methods: The cross-sectional study included 311 Venda men (18–40 years) from DDT-sprayed villages and 150 men from similar ethnic and socioeconomic backgrounds living in nonsprayed villages. Complete semen analyses were conducted according to the methods of the World Health Organization (1999), and blood samples were assayed for testosterone, thyroid function, and DDT and its metabolites. Computer-assisted sperm motion analysis (CASA) was used to determine additional sperm motility parameters, and sperm chromatin integrity was measured. Results: The p,p′-DDT lipid-adjusted concentration in men from the sprayed area was 90.23 ± 102.4 μg/g compared with 1.92 ± 1.4 μg/g in the men from the reference area. The major metabolite, p,p′-DDE, measured 215.47 ± 210.6 μg/g in exposed men compared with 1.66 ± 1.9 μg/g in the reference group. Various seminal parameters, including sperm motility parameters and the percentage motile sperm were impaired with higher p,p′-DDT and p,p′-DDE concentrations (r = −0.27, P < 0.001 and r = −0.20, P < 0.001, respectively) in the exposed men. No associations were found with any of the seminal parameters or hormones in the reference group. The mean testosterone level of the DDT-exposed men (23.60 ± 9.1 nmol/L) was higher than that in reference group (20.70 ± 6.1 nmol/L). Conclusions: Exposure to DDT was associated with impaired semen quality, suggesting adverse effects on testicular function and/or the regulation of reproductive hormones. The low exposure levels in those living in nonsprayed villages confirmed that direct DDT exposure was possibly a result of the IRS. The high exposure levels of DDT and p,p′-DDE in South Africa are of reason for concern as it seems likely that IRS using DDT may have long-term negative impacts on reproductive health.