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DDT metabolite and androgens in African-American farmers
Stephen A Martin1, Siobán D Harlow, Mary Fran Sowers
1National Institute of Environmental Health Sciences, Epidemiology Branch, MD A3-05, Research Triangle Park, NC 27709, USA.
Background:
The ubiquitous dichlorodiphenyltrichloroethane (DDT) metabolite 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) is an androgen receptor antagonist. Data on potential antiandrogenic activity of DDE in humans are limited.
Methods:
The relations between concentrations of plasma DDE and several serum androgens (total testosterone, bioavailable testosterone, 5alpha-dihydrotestosterone, and free androgen index) were examined in 137 North Carolina black male farmers, using multiple linear regression.
Results:
Participants ranged in age from 30 to 88 years (mean = 62 years). Most had farmed for about 30 years and 27% reported having used DDT. The median DDE level was 7.7 microg per liter (1213 microg per kg lipid), slightly higher than in other recent studies. Overall, concentrations of DDE and androgens were unrelated. Total testosterone decreased 2% (95% confidence limits [CL] = -9%, 5%) per increase in interquartile distance of lipid-adjusted DDE. The percentage change in other hormones was similarly negligible. However, among those whose DDE level was in the top tenth percentile, compared with all others, total testosterone and free androgen index were lower by 23% (CL= -40%, 1%) and 22% (CL =-41%, 4%) respectively. Plasma androgen levels decreased with age, a relation that has previously been studied only in whites.
Conclusions:
Studies of more highly exposed populations may be needed to evaluate effects, if any, of DDE.