Do Perfluoroalkyl Compounds Impair Human Semen Quality?

Ulla Nordström; Joensen Rossana Bossi; Henrik Leffers; Allan Astrup Jensen; Niels E. Skakkebæk; Niels Jørgensen

Disclosures

Environ Health Perspect. 2009;117(6):923-927. 

In This Article

Abstract and Introduction

Abstract

Background: Perfluoroalkyl acids (PFAAs) are found globally in wildlife and humans and are suspected to act as endocrine disruptors. There are no previous reports of PFAA levels in adult men from Denmark or of a possible association between semen quality and PFAA exposure.
Objectives: We investigated possible associations between PFAAs and testicular function. We hypothesized that higher PFAA levels would be associated with lower semen quality and lower testosterone levels.
Methods: We analyzed serum samples for levels of 10 different PFAAs and reproductive hormones and assessed semen quality in 105 Danish men from the general population (median age, 19 years).
Results: Considerable levels of perfluorooctane sulfonic acid (PFOS) , perfluorooctanoic acid (PFOA) , and perfluorohexane sulfonic acid were found in all young men (medians of 24.5, 4.9, and 6.6 ng/mL, respectively) . Men with high combined levels of PFOS and PFOA had a median of 6.2 million normal spermatozoa in their ejaculate in contrast to 15.5 million among men with low PFOS–PFOA (p = 0.030) . In addition, we found nonsignificant trends with regard to lower sperm concentration, lower total sperm counts, and altered pituitary–gonadal hormones among men with high PFOS–PFOA levels.
Conclusion: High PFAA levels were associated with fewer normal sperm. Thus, high levels of PFAAs may contribute to the otherwise unexplained low semen quality often seen in young men. However, our findings need to be corroborated in larger studies.

Introduction

Perfluoroalkyl acids (PFAAs) are degradation products of many man-made polyfluorinated compounds (PFCs) used in consumer and industrial products, for example, for impregnation of carpets, textiles, and paper (Jensen et al. 2008; Jensen and Leffers 2008; Kissa 2001). Studies of environment, wildlife, and humans suggest widespread presence and exposure, persistence in the environment, and bioaccumulation (Giesy and Kannan 2001; Kannan et al. 2004). For perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorohexane sulfonic acid (PFHxS), three of the most abundant PFAAs, half-lives for humans have been estimated as 3.8, 5.4, and 8.5 years, respectively (Olsen et al. 2007). Some studies suggest that men may have higher serum concentrations of PFAAs than women, and younger individuals may have higher levels than older (Calafat et al. 2006). Thus, young men may have particularly high levels of exposure and may therefore be a group at risk for potential adverse effects of PFAAs.

PFAAs can cross the placental barrier and therefore have the potential to affect the fetus. In humans, levels of PFOS and PFOA in umbilical cord blood have been inversely related to birth weight (Apelberg et al. 2007). In addition, PFOS, PFOA, and PFHxS have been detected in human seminal plasma samples (Guruge et al. 2005). However, data on effects in humans are scarce, and most come from studies of occupationally exposed individuals. These studies have not given conclusive evidence of adverse effects. In a recent study, however, Fei et al. (2009) measured PFAA levels in early pregnancy and found that higher levels of PFOS and PFOA were associated with significantly longer waiting time to pregnancy.

Animal studies provide some evidence for adverse reproductive effects on animals exposed as adults or in utero. Exposure of adult male rats to PFOA reduced their testosterone levels and increased their estradiol levels, which may partly explain earlier findings of induction of Leydig cell hyperplasia and/or adenomas in the testes of exposed animals (Biegel et al. 1995; Cook et al. 1992).

Our objective in the present study was to investigate the associations between PFOS, PFOA, PFHxS, and other PFAAs and testicular function. Our primary hypothesis was that high concentrations of PFAAs would be associated with low testosterone levels and that high PFAA levels are negatively associated with semen quality variables.

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