This study is performed by Lærke Priskorn at Department of Growth and Reproduction, Rigshospitalet, Denmark, in collaboration with Lund University, Sweden.

Background and results
Semen samples from 18-20-year-old men from the general population have since 1996 been collected at Rigshospitalet. More than 6.000 men are included in this data base. Approximately 35% of these men have low semen quality. Overall, there has been no persistent trend in semen quality over the 20-year period of this study. Exposure to maternal smoking is associated with lower sperm counts but no overall increase in sperm count was observed between 1996 and 2016 despite a decrease in this exposure from 40% among men investigated in 1996-2000 to 18% among men investigated in 2011-2016. This suggest that other unknown factors may maintain the low semen quality among Danish men.

It has been documented that an impaired semen quality is followed by a higher morbidity and mortality risk. The mechanisms behind this association between semen quality and future health is, however, largely unknown, but common fetal origin (e.g. maternal lifestyle or exposure to endocrine disrupting compounds), genetic factors or adult lifestyle are possible explanations.

This project is a continuation of previous studies in young men focusing on early markers of health. Extensive health data on nearly 900 young Danish men has been collected, including information on general health markers (e.g. lipids and markers of liver and kidney function), bone mineral density and body composition. A new mass spectrophotometric analysis performed at Lund University will try to identify proteomic biomarkers that can add information to the understanding of the pathogenesis of male infertility and associated disorders.

The hypothesis behind this study is that there may be a connection between the men’s semen quality and the different health parameters already at a young age, which could be useful information for future programs aiming at preventing the excess morbidity and mortality observed in infertile men.

Publication: Priskorn et al. Average sperm count remains unchanged despite reduction in maternal smoking: results from a large cross-sectional study with annual investigations over 21 years. Human Reproduction  33(6):998–1008.

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