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Deterioration of sperm quality in young healthy Belgian men
K Van Waeleghem1, N De Clercq, L Vermeulen
1University Hospital, Ghent, Belgium.
Insights
Sperm quality has declined significantly in young men over 19 years, with reduced motility and morphology. This trend suggests a decline in sperm production among men aged 20-40.
Area of Science:
- Reproductive Health
- Andrology
- Human Reproduction Research
Background:
- Sperm characteristics are crucial indicators of male reproductive health.
- Trends in sperm quality over time are essential for understanding population-level fertility.
- Previous studies have indicated potential declines in sperm parameters, necessitating further investigation.
Purpose of the Study:
- To retrospectively analyze changes in sperm characteristics of healthy young men over a 19-year period.
- To identify time-related trends in ejaculate volume, sperm concentration, count, morphology, and motility.
- To assess the proportion of candidate sperm donors with sperm parameters below established normal ranges.
Main Methods:
- Retrospective analysis of semen analysis data from 416 healthy young men (candidate sperm donors).
- Data collected over a 19-year period.
- Statistical analysis to evaluate trends in sperm volume, concentration, count, morphology, and motility (progressive and total).
Main Results:
- Average sperm concentration decreased significantly, while ejaculate volume showed a slight increase.
- Sperm morphology and rapid progressive motility exhibited significant time-related declines.
- The proportion of donors with sperm characteristics below the 5th percentile of a normal fertile population increased substantially from 13% to 54%.
Conclusions:
- A significant deterioration in sperm quality, particularly morphology and motility, has been observed in young men over the past 19 years.
- The findings suggest a potential degeneration in sperm production among men aged 20-40.
- The consistent methodology for semen analysis and donor recruitment supports the conclusion that these changes reflect a real decline in sperm characteristics.
Abstract:
We have retrospectively analysed the sperm characteristics of 416 consecutive healthy young men who presented themselves in the past 19 years as candidate sperm donors. Ejaculate volume increased slightly (P = 0.067), and average sperm concentration decreased (P = 0.035) by 12.4 x 10(6)/ml over the observation period, so that sperm count per ejaculate remained unchanged (P = 0.91). In contrast, sperm morphology (r = - 0.23, P < 0.0001), rapid progressive motility (r = - 0.42, P < 0.0001) and total motility (r = - 0.33, P < 0.0001) presented an important and time-related decrease. When a quadratic model was used rather than a linear one to analyse the data on rapid progressive motility, there appeared to have been no further decline since 1990. The average proportion of spermatozoa with normal morphology decreased from 39.2% in the period 1977-1980 to 26.6% in 1990-1995 (P < 0.0001), and the mean percentage of spermatozoa with rapid progressive motility decreased from 52.7 to 31.7% (P < 0.0001). The percentage of candidate donors with sperm characteristics below the 5th percentile cut-off value of a normal fertile population increased from 13 to 54% during the observation period (P < 0.0001). Since the technique of semen analysis has remained essentially unchanged in-so-far as has been practically possible, as has the method of recruitment of candidate sperm donors, the observed deterioration of sperm characteristics is considered to reflect degeneration of sperm production among men aged between 20 and 40 years.