Urinary Bisphenol A concentrations and human semen quality

Abstract

OBJECTIVE: Bisphenol A is used to manufacture polymeric materials and can be found in a wide variety of consumer products. These include polycarbonate plastic baby and water bottles, epoxy resins which may be used as the lacquer lining of food and beverage cans and some dental sealants and composites. Recent data from the CDC found BPA in 93% of urine samples from a reference population of U.S. citizens (NHANES 2003-2004). Because of demonstrated widespread human exposure and reproductive and developmental effects at low levels in experimental animals, there has been an increase in concern over potential adverse effects of BPA on human health. Rodent studies have shown an association between exposure to environmentally relevant low doses of BPA and decreased semen quality. In these animal studies, daily sperm production and sperm count decreased by up to 40%. Sperm motility decreased and abnormal spermatids increased. DESIGN: A prospective cohort study. MATERIALS AND METHODS: The study population included 71 male partners of couples from the Massachusetts General Hospital Fertility Center. Each man provided at least one semen and urine sample; thity nine men (55%) provided more than one urine and semen sample. Ninety-six percent of the urine samples were collected within 7 days of the semen sample, with only six urine samples collected within 8 or more days (maximum was 27 days) of the semen sample. RESULTS: The mean total urinary BPA level for the 142 urine samples was 2.41mg/L (range <0.4 (below LOD) – 18.70 mg/L). Analysis of the association of urinary BPA with semen parameters (sperm concentration, motility and morphology) is in progress. The semen parameters will be analyzed as both a continuous variable and dichotomized using WHO reference values for sperm concentration (<20million/mL) and motility (<50% motile) and Strict criteria for morphology (<4% normal).As expected, there was high intra-individual variability of both urinary BPA concentrations and semen parameters. In preliminary analyses, there were not strong associations of BPA with semen quality parameters. CONCLUSIONS: The lack of an association of urinary BPA concentrations with semen parameters should be interpreted cautiously due to the small sample size. Future statistical analyses will include additional men.