Is semen quality related to the year of birth among Danish infertility clients ?
There is circumstantial evidence that human sperm count may have declined during past decades.
The purpose of this study was to identify the association between semen quality and year of birth.
The study comprised 8608 men consulting four Danish medical centres from 1968 to 1992 because of infertility.
Data on semen quality and urogenital disorders were obtained from medical records while lifestyle data were collected from a subset of the population by a postal questionnaire (response 80%). Semen characteristics were analysed as a linear function of year of birth, centre, season and calendar year at time of semen examination, sexual abstinence and lifestyle factors.
Effects of age were accounted for by restriction and stratified analysis.
The sperm count declined with increasing year of birth at two of the four centres, but this association disappeared when confounders were adjusted for.
Within the subset of men born 1950-1970 we revealed a decrease in the average sperm count by 1.9 mill/ml (95% confidence interval [Cl] : 1.45,2.27) per one advancing year of birth.
This finding was consistent across centres even after adjustment for effects of covariates.
The proportion of morphologically normal sperm cells changed in parallel with the sperm count, while semen volume did not decline in any time periods. (...)
Mots-clés Pascal : Sperme, Stérilité, Epidémiologie, Homme, Mâle, Tendance, Variation séculaire, Danemark, Europe, Année naissance
Mots-clés Pascal anglais : Semen, Sterility, Epidemiology, Human, Male, Trend, Secular variation, Denmark, Europe
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 98-0056872
Code Inist : 002B20A04. Création : 14/05/1998.