Bisphenol A exposure and reduced male sex hormone levels in a Norwegian population

Abstract

Background: Bisphenol A (BPA) is used in production of polycarbonate plastics and epoxy resins. Despite endocrine disrupting properties and suspected impact on male reproductive health BPA is still frequently used in a wide variety of consumer products. Few studies have addressed BPA exposure and steroid hormones in a general population sample. We aimed to investigate whether BPA exposure is associated with steroid hormone concentrations (17β-estradiol, estrone, estrone 3-sulfate, progesterone, progesterone 17α-OH-progesterone, testosterone, androstenedione, dehydroepiandrosterone sulfate (DHEAS), aldosterone, cortisone and cortisol) in a healthy Norwegian population. Methods: The study included 205 women and 232 men aged 18-48 years, participating in the RHINESSA study (2014-15) in Norway. Urine concentration of BPA and steroid hormones in serum were measured using liquid chromatography - mass spectrometry. We applied linear mixed effects random intercept models with sex hormone levels (one at a time) as outcome, BPA concentration as exposure and adjusted for age, sex, BMI, smoking and time of day for urine and blood sampling. Results: Bisphenol A was detected in 96% of the urine samples; and median concentration was 1.32 ng/mL (5th-95th percentile: 0.50-5.15, max: 21.9 ng/mL). Increasing exposure to BPA (per ng/mL) was associated with decreasing levels of testosterone (-11.72 pmol/cL, 95% Confidence Interval (CI): -22.93, -0.51) and DHEAS (-6.83 nmol/cL, 95% CI: -12.72, -0.94) for men and women combined. Restricting the analyses to men, increasing exposure to BPA was associated with decreasing levels of 17β-estradiol (-0.88 pmol/L, 95% CI: -1.72, -0.04) and with elevated endogenous aldosterone levels (4.32 pmol/L, 95% CI: 0.91, 7.73). Conclusions: The urinary biomarker concentration of BPA is ubiquitous, but relatively low. BPA was associated with an altered hormone profile, in particular with reduced levels of androgens as well as with 17β-estradiol which is synthesized from androgen precursors. Whether the association is of clinical relevance needs to be elucidated.