Semen quality improves marginally during young adulthood: a longitudinal follow-up study
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STUDY QUESTION: Does semen quality improve during early adulthood?
SUMMARY ANSWER: Semen variables change little during the third decade of life, however some improvement in sperm morphology and motility may occur.
WHAT IS KNOWN ALREADY: A suspicion of deteriorating semen quality has been raised in several studies. The longitudinal development of semen quality in early adulthood is insufficiently understood.
STUDY DESIGN, SIZE, DURATION: A longitudinal follow-up of two cohorts of volunteer young adult Finnish men representing the general population was carried out. Cohorts A (discovery cohort, born 1979-1981, n = 336) and B (validation cohort, born 1983, n = 197) were followed up from the age of 19 years onward for 10 years.
PARTICIPANTS/MATERIALS, SETTING, METHODS: Inclusion criteria included that both the men and their mothers were born in Finland. Semen analysis was performed in cohorts A and B at 2-4 year intervals over a period of 10 years. Semen volume, sperm concentration, total sperm count, motility, total motile count and morphology were the variables assessed in the analysis. A physical examination was carried out at each visit to detect any significant andrological abnormalities. The overall participation rate was 13.4%.
MAIN RESULTS AND THE ROLE OF CHANCE: During the follow-up, the percentage of sperm with normal morphology and the percentage of motile sperm increased significantly both in the discovery (A) (P < 0.001 at 19 versus 29 years for both) and validation (B) (P < 0.001 and P = 0.03 at 19 versus 29 years, respectively) cohort. Sperm concentration and total sperm count showed a significant increase with age only in cohort B (P = 0.03 at 21 versus 29 years, P = 0.009 at 19 versus 29 years, respectively).
LIMITATIONS, REASONS FOR CAUTION: A limited number of men participated both in the first round and in the final fourth round (cohort A, n = 111 and cohort B, n = 90 men) and in all four rounds (cohort A, n = 61 and cohort B, n = 52).
WIDER IMPLICATIONS OF THE FINDINGS: Almost full spermatogenic capacity is reached by the age of 19 years. However, the improvement in sperm motility and morphology during early adulthood may slightly improve male fecundity.
STUDY FUNDING/COMPETING INTERESTS: This study was supported by the European Commission (QLK4-CT-1999-01422, QLK4-CT-2001-00269, QLK4-2002-0063, FP7/2008-2012: DEER 212844), The Danish Medical Research Council (9700833, 9700909), Danish Agency for Science (Technology and Innovation 09-067180), the Svend Andersen's Foundation, Velux Foundation, and Novo Nordisk Foundation, the Turku University Hospital, Sigrid Jusélius Foundation and the Academy of Finland. There are no conflicts of interest.
Original language | English |
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Journal | Human Reproduction |
Volume | 31 |
Issue number | 3 |
Pages (from-to) | 502-10 |
Number of pages | 9 |
ISSN | 0268-1161 |
DOIs | |
Publication status | Published - 2016 |
- Adult, Age Factors, Finland, Humans, Longitudinal Studies, Male, Multivariate Analysis, Reproductive Health, Semen Analysis, Sperm Count, Sperm Motility, Spermatogenesis, Journal Article, Research Support, Non-U.S. Gov't
Research areas
ID: 176835381