The first-ever nationwide testing of young Swiss men has found that over 60% have below average sperm count, mobility or morphology.
Researchers from the University of Geneva tested over 2,500 army recruits aged between 18 and 22. With a median of 47 million sperms per millilitre, the Swiss are at the bottom of the pack along with Denmark, Norway and Germany. The European median ranges from 41 to 67 million per ml.
"It is important to know that below 40 million sperm per ml, the time needed to conceive a baby increases significantly," said Serge Nef, one of the co-authors of the study.
When compared with the World Health Organizationexternal link (WHO) benchmarks established in 2010, 17% of those tested have sperm counts of less than 15 million per ml. A man with a sperm count below 15 million per ml can be considered sub-fertile and is likely to have problems conceiving a child. Infertility is defined as the inability to conceive after 12 months of regular unprotected sex.
It is not just sperm count that is cause for concern. Sperm mobility was also found to be low among those tested, with a quarter having lower than 40% sperm mobility. In addition, 40% have less than 4% morphologically normal sperm. In total, 60% of those tested have at least one of these three parameters (concentration, mobility and morphology) below WHO standards. About 5% have a problem on all three fronts.
Smoking by mothers during pregnancy was found to correlate with poor sperm quality. Among the sub-fertile men, 18% had mothers who smoked compared to 11% among those with relatively healthy sperm. Correlation, however, does not mean causality.
The scientists cautioned against making assumptions on fertility based on a single spermogram. The results suggest that the sperm quality of young men in Switzerland is not optimal and may well compromise their fertility.
Biomonitoring study on sperm quality
In response to the University of Geneva study findings, the Federal Office of Public Health (FOPH) announced it is launching a pilot project on so-called human biomonitoring to determine whether certain harmful substances are responsible for poor sperm quality in Swiss men.
The aim of the study is to understand what and to what extent pollutants are affecting sperm quality, which will inform measures the health sector can take to restrict such substances.
The research project will start this fall with 1,000 people from German and French-speaking Switzerland. Throughout the year, study participants will visit the study site for health check-ups, to provide blood and urine samples, and answer questions about their health and environment. If the pilot phase shows positive results, the study could be expanded to 100,000 participants.