Environmental Exposure to Polychlorinated Biphenyls and p, p′-DDE and Sperm Sex-Chromosome Disomy

BACKGROUND: Chromosomal abnormalities contribute substantially to reproductive problems, but the role of environmental risk factors has received little attention. OBJECTIVES: We evaluated the association of polychlorinated biphenyl (PCB) and dichlorodiphenyldichloroethylene (p, p'-DDE) exposures with sperm sex-chromosome disomy. METHODS: We conducted a cross-sectional study of 192 men from subfertile couples. We used multiprobe fluorescence in situ hybridization (FISH) for chromosomes X, Y, and 18 to determine XX, YY, XY, and total sex-chromosome disomy in sperm nuclei. Serum was analyzed for concentrations of 57 PCB congeners and p, p'-DDE. Poisson regression models were used to calculate incidence rate ratios (IRRs) for disomy by exposure quartiles, controlling for demographic characteristics and semen parameters. RESULTS: The median percent disomy was 0.3 for XX and YY, 0.9 for XY, and 1.6 for total sex-chromosome disomy. We observed a significant trend of increasing IRRs for increasing quartiles of p, p'-DDE in XX, XY, and total sex-chromosome disomy, and a significant trend of increasing IRRs for increasing quartiles of PCBs for XY and total sex-chromosome disomy; however, there was a significant inverse association for XX disomy. CONCLUSIONS: Our findings suggest that exposure to p, p'-DDE may be associated with increased rates of XX, XY, and total sex-chromosome disomy, whereas exposure to PCBs may be associated with increased rates of YY, XY, and total sex-chromosome disomy. In addition, we observed an inverse association between increased exposure to PCBs and XX disomy. Further work is needed to confirm these findings.