Perfluorinated compounds and male reproductive function

Introduction
There is only limited evidence on the effects of perfluorinated compounds on male reproductive function. Animal studies indicates that high concentrations of perfluorooctanesulfonic acid (PFOS) may damage sperm cell production in mice, probably through disturbances in enzyme activity involved in sexual hormone production. Multigenerational studies in rats indicates that perfluorooctanoic acid (PFOA) is probably not affecting male reproductive function. A study including 105 Danish men indicated that the proportion of morphological normal sperm cells was lower among men with a high combined intake of PFOS and PFOA, while the study found no statistical significant associations to other sperm parameters.

Methods
A cross sectional study on the association of semen quality to PFOS and PFOA measured in serum samples were performed among 591 fertile men from Greenland, Ukraine and Poland. Semen quality was assessed according to the WHO guidelines, and extensive quality control was performed to assure comparable results from the three countries included in the study.

Results
The concentration of perfluorerinated compounds in male serum samples varies considerably between countries with median level of PFOS ranging from a median of 44.7 ng/ml in Greenland to 18.5 ng/ml in Poland and 7.6 ng/ml in Ukraine. PFOA varies less (4.5; 4.8 and 1.3 ng/ml) in Greenland, Poland and Ukraine, respectively. Sperm concentration, total sperm count and sperm cell motility was not statistically significantly associated to PFOS or PFOA but the proportion of normal sperm cells was 22%; confidence interval (1 to 44%) and 35% (4 to 66%) lower at the second and third tertile of PFOS exposure compared to the first tertile.

Discussion
The present study confirms results from the previous study on negative associations between exposure to perfluorinated compounds and sperm cell morphology and suggests that PFOS may be the causal agent.