TY - JOUR

T1 - Semen quality improves marginally during young adulthood

T2 - a longitudinal follow-up study

AU - Perheentupa, Antti

AU - Sadov, Sergey

AU - Rönkä, Riitta

AU - Virtanen, Helena E.

AU - Rodprasert, Wiwat

AU - Vierula, Matti

AU - Jørgensen, Niels

AU - Skakkebæk, Niels E

AU - Toppari, Jorma

N1 - © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology.

PY - 2016

Y1 - 2016

N2 - 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.

AB - 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.

KW - Adult

KW - Age Factors

KW - Finland

KW - Humans

KW - Longitudinal Studies

KW - Male

KW - Multivariate Analysis

KW - Reproductive Health

KW - Semen Analysis

KW - Sperm Count

KW - Sperm Motility

KW - Spermatogenesis

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

U2 - 10.1093/humrep/dev328

DO - 10.1093/humrep/dev328

M3 - Journal article

C2 - 26740579

VL - 31

SP - 502

EP - 510

JO - Human Reproduction

JF - Human Reproduction

SN - 0268-1161

IS - 3

ER -