Endocrine disrupting chemicals in urine of Japanese male partners of subfertile couples: a pilot study on exposure and semen quality

Abstract

The concentrations of chemicals with suspected endocrine disrupting effect were measured in urine samples collected from 42 Japanese male partners of couples who had infertility consultation at a gynecology clinic in Tokyo. The urinary analytes included metabolites of 5 phthalate diesters, pyrethroid insecticide (3-phenoxybenzoic acid, 3-PBA) and soy isoflavones (daidzein and equol), and cadmium. The semen parameters (semen volume, concentration and motility) of the male subjects were examined at the clinic as a diagnostic screening. Multiple regression analysis using one of the semen parameters examined as dependent variable and urinary biomarkers with age, body mass index, abstinent period, alcohol drinking, smoking and consumption frequency of selected foods as independent variables. For sperm concentration, urinary mono-n-butyl phthalate was selected as a significant independent variable with positive beta, while urinary daidzein was with negative beta. Consumption frequency of coffee (negative) and fruits (positive) were also significant. For sperm motility, urinary 3-PBA was selected as significant with negative beta as well as detectability of equol and frequency of coffee consumption with negative beta while smoking was with positive beta. This pilot study suggested the pyrethroid exposure level and dietary habit (coffee and soy products) as a significant contributor to poorer semen quality.