Exposures to air pollution and endocrine disruptors and measures of semen quality in a population based cohort of US men

Abstract

Background: Multiple studies have identified adverse associations between exposures to air pollution and endocrine disrupting chemicals on semen quality. However, few studies have assessed these associations among men from the general population, as opposed to clinical settings. Our objective was to assess these associations in a subset of participants in the US nationwide Growing Up Today Study (GUTS).Methods: We aim to enroll 200 men from GUTS living in the conterminous US, without a vasectomy, are who have not undergone chemotherapy, and are not taking anabolic steroids. For 90 days, participants use a smartphone application to track GPS location, run an air pollution sampler to collect real-time indoor measurements of NO2, and wear 3 separate passive wristband samplers each for 30 days. After 90 days of monitoring, participants produce a semen sample, which is analyzed for concentration and morphology at the Massachusetts General Hospital Andrology Laboratory via computer-aided semen analysis. For the first 45 participants, we assessed the interclass correlation (ICC) of exposures and assessed associations between exposures and outcomes using Spearman correlations and linear regressions.Results: The average NO2 concentration was 18.11 (SD=10.2) ppb and 21 chemicals were detected in at least 20% of wristbands measured. The ICC for daily NO2 was 0.71 (95%CI: 0.61, 0.79), the ICCs for the 21 chemicals varied widely, ranging from 0.04 (0.00, 0.97) for dicyclohexyl phthalate to 0.88 (0.78, 0.94) for galaxolide. Ninety-day average exposures to NO2 were not associated percent normal morphology, but were associated with decreased sperm concentration (-12.09 M/ml per IQR (14.49 ppb) NO2). There were no clear patterns observed between the EDC exposures and semen parameters.Conclusions: In an initial subsample of general population men, exposures to NO2, but not endocrine disrupting chemicals, were associated with lower sperm concentrations.