Evaluation of sperm quality at a national level: Logistic, recruitment, analytical and statistical problems encountered in switzerland

Josefina Vargas, Roumen Parapanov, Marc Van Den Bergh, Eric Stettler, Pierre Crettaz, Alfred Senn, Marc Germond

Fondation Faber, Lausanne, Switzerland, Kantonspital Baden Ag, Fertilitätslabor, Switzerland, Swiss Army Medical Services, Switzerland, Federal Office of Public Health, Switzerland

Aim:
For decades, numerous studies have reported a decline in sperm quality among industrialised countries. Explanations for this decline point toward environmental factors acting on animals and humans. More recently, the detrimental role of endocrine disruptors during foetal development of the testicles has also been hypothesised. In order to test whether these effects are operating in Switzerland, a survey study among Swiss young men was initiated in 2005 and will cover within the next two years the entire country. The aim of this report is to present the differences in sperm quality observed so far in various geographic regions of the Switzerland.
Method:
One month before recruitment, all conscripts are informed about the study. When interested, the volunteers send a consent form and two questionnaires to the Swiss army physician in charge of supervising the study and warranting anonymity. Four recruiting centres (Lausanne, Rüti, Windisch, Monte Ceneri) are actively involved in the sample collection phase. At the end of their recruiting camp, volunteers are invited in a nearby laboratory for biological investigations. Sperm samples are analysed according to WHO recommendations. Sperm concentration, motility and morphology are measured using a computerised system (CASA, SCA Microptic, Spain).
Results:
Results are grouped according to a geographic stratification of Switzerland into (1) Plateau west and central, (2) Jura, (3) Alps, (4) Plateau north and east. Medians for sperm concentration were significantly lower in regions 3 and 4 compared to the two other regions, whereas sperm motility was less affected.
Conclusion:
The geographic differences observed in sperm quality throughout Switzerland are currently further investigated by enlarging the cohort and identifying possible explanations for such differences. A human biomonitoring is underway in order to identify the presence of various endocrine disruptors in serum and urine samples collected from the volunteers.

doi: 10.1016/S1472-6483(10)62403-0