Pesticide exposure and risk of hypospadias: assessment and the adequacy of exposure measurements

Hypospadias is a congenital malformation that occurs in 0.3-1% of live births, in which the meatus (the urethral opening) is dorsally malpositioned. Uncorrected hypospadias can cause difficulties in urination, abnormal sexual function, and adverse psychological consequences; surgical correction, though generally successful, constitutes an economic burden for families. Several common classes of pesticides have demonstrated potential to disrupt normal endocrine hormones that regulate fetal genitourinary development. Past epidemiologic studies of pesticide exposure and risk of hypospadias have been limited by limited available data, small sample sizes, or poor ascertainment of pesticide exposure. The objective of this study was to examine the relationship between parental occupational pesticide exposure and risk of hypospadias in their offspring; and further, to assess whether addition of residential pesticide exposure data is feasible and contributes to overall pesticide exposure. We began by conducting a meta-analysis of the current literature, in which summary measures of occupation (such as census occupation code) had been used to assign pesticide exposure. We found elevated but marginally significant risks of hypospadias were associated with maternal occupational exposure (PRR of 1.36, CI = 1.04-1.77), and paternal occupational exposure (PRR of 1.19, CI= 1.00-1.41) in the previously published literature. We then used industrial hygienist review of occupational histories to estimate the relationship between pesticide exposure and risk of hypospadias. We found that maternal occupational exposure to any pesticides (yes/no) was not associated with an increased risk of hypospadias (OR = 0.83, 95% CI = 0.6-1.1), cumulative insecticide (OR = 1.09;