Abstract A83: Organophosphate pesticides and sex steroid hormones in NHANES III

Organophosphate pesticides (OP) may perturb hormone balance, and thus may affect men’s health, e.g., prostate cancer. We evaluated whether men from the general population with higher urinary OP metabolites had higher or lower concentrations of sex steroid hormones than men with lower levels.

Concentrations of 3,5,6-trichloro-2-pyridinol (TCPY), a chlorpyrifos metabolite, and 4-nitrophenol (4-NP), a methyl parathion metabolite, previously were measured in spot urine for 1,338 men ages 20-59 who participated in the Third National Health and Nutrition Examination Survey (NHANES III). We measured serum concentrations of testosterone, estradiol, and sex hormone binding globulin (SHBG) for 1,637 men ≥ 12 years old who participated in the morning session of Phase I of NHANES III. 189 men participated in both sub-studies, forming the study population. Linear regression was used to estimate geometric mean hormone concentration by binary category of creatinine-corrected urinary OP concentration adjusting for age, US region, smoking, race, education, body mass index, and physical activity. We tested for trend across quartiles of TCPY and across 3 categories (< limit of detection (LOD), 2 categories ≥ LOD) of 4-NP by entering a single ordinal term in the model with values at the category medians, the coefficient for which was evaluated by the Wald test.

Mean testosterone (95% confidence interval) was significantly higher in men with higher TCPY (≥ median: 5.55 (4.95, 6.22)) compared with lower (<median: (4.93 (4.43, 5.48)). Although not statistically significant, mean estradiol and SHBG concentrations were also higher comparing higher to lower TCPY. There was no statistically significant difference in mean testosterone (<LOD: 5.44 (4.85, 6.10); ≥LOD: 5.14 (4.54, 5.83)) or estradiol (<LOD: 37.83 (34.88, 41.03); ≥LOD: 35.94 (32.94, 39.21)) between men with 4-NP concentration ≥LOD versus <LOD, although men with higher 4-NP tended to have lower hormone levels. SHBG did not differ by 4-NP category. None of the trends was significant (p>0.10).

This cross-sectional study, the first in a general population of US adult men, suggests positive associations of chlorpyrifos with testosterone, estradiol, SHBG, and inverse associations of methyl parathion with testosterone and estradiol. These findings differ somewhat from those in occupationally-exposed groups. Given that a) our findings are compatible with the hypothesis that OPs influence hormones even at low exposure, b) OPs were available to consumers and commonly used, and c) a prior study observed a higher prostate cancer risk in commercial applicators who used an OP and had a family history of prostate cancer (Am J Epidemiol 2003;157:800-14), future studies are warranted on OPs and men’s health, including prostate cancer.

Funding: Maryland Cigarette Restitution Fund at Johns Hopkins

Citation Information: Cancer Prev Res 2008;1(7 Suppl):A83.