Environmental exposure to pyrethroids and sperm sex chromosome disomy: a cross-sectional study

Heather A Young,Melissa J Perry,Dana Boyd Barr,Zaida I Figueroa,John D Meeker,Sheena E Martenies

doi:10.1186/1476-069x-12-111

Abstract

BackgroundThe role of environmental pesticide exposures, such as pyrethroids, and their relationship to sperm abnormalities are not well understood. This study investigated whether environmental exposure to pyrethroids was associated with altered frequency of sperm sex chromosome disomy in adult men.MethodsA sample of 75 subjects recruited through a Massachusetts infertility clinic provided urine and semen samples. Individual exposures were measured as urinary concentrations of three pyrethroid metabolites ((3-phenoxybenzoic acid (3PBA), cis- and trans- 3-(2,2-Dichlorovinyl)-1-methylcyclopropane-1,2-dicarboxylic acid (CDCCA and TDCCA)). Multiprobe fluorescence in situ hybridization for chromosomes X, Y, and 18 was used to determine XX, YY, XY, 1818, and total sex chromosome disomy in sperm nuclei. Poisson regression analysis was used to examine the association between aneuploidy rates and pyrethroid metabolites while adjusting for covariates.ResultsBetween 25-56% of the sample were above the limit of detection (LOD) for the pyrethroid metabolites. All sex chromosome disomies were increased by 7-30% when comparing men with CDCCA and TDCCA levels above the LOD to those below the LOD. For 3PBA, compared to those below the LOD, those above the LOD had YY18 disomy rates 1.28 times higher (95% CI: 1.15, 1.42) whereas a reduced rate was seen for XY18 and total disomy (IRR = 0.82; 95% CI: 0.77, 0.87; IRR = 0.93; 95% CI: 0.87-0.97), and no association was seen for XX18 and 1818.ConclusionsOur findings suggest that urinary concentrations of CDCCA and TDCCA above the LOD were associated with increased rates of aneuploidy. However the findings for 3BPA were not consistent. This is the first study to examine these relationships, and replication of our findings is needed before the association between pyrethroid metabolites and aneuploidy can be fully defined.

Highlights

The role of environmental pesticide exposures, such as pyrethroids, and their relationship to sperm abnormalities are not well understood
Pyrethroids (PYRs), a family of synthetic insecticides which are structurally based on the natural pesticide pyrethrum [11], have been identified as potential endocrine disruptors [10,12,13,14]
Our results showed consistent increased risks ranging between 7-30% of XX, YY, XY, and total sex chromosome disomy among those with higher levels of PYR metabolites (CDCCA and TDCCA) after adjustment for potential confounders

Summary

Introduction

The role of environmental pesticide exposures, such as pyrethroids, and their relationship to sperm abnormalities are not well understood. Sex chromosomes are susceptible to aneuploidy and sperm that are sex chromosome aneuploid are viable and can result in offspring with fertility conditions such as Klinefelter Syndrome, Turner Syndrome [1,7,8,9]. Chemicals such as pesticides are known to disrupt hormone signaling that may interfere with recombination sequences [10], and prior epidemiologic studies have shown associations between occupational pesticide use and sperm aneuploidy (reviewed in 11). Pyrethroids (PYRs), a family of synthetic insecticides which are structurally based on the natural pesticide pyrethrum [11], have been identified as potential endocrine disruptors [10,12,13,14]

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Conclusion