title: Evolution of semen quality in North-eastern Spain: a study in 22,759 infertile men over a 36 year period.
abstract: A retrospective study was conducted in a large population to determine whether sperm quality has changed in Northeastern Spain between 1960 and 1996. From a total initial population of 22,759 men, two separate groups were studied: men with spermatozoa (n = 20,411) and those with azoospermia (n = 1364). After adjustment for age and sexual abstinence, multiple linear regression analyses were used to assess changes in semen parameters over time. A 0.2% decline was observed in semen volume in the spermatozoa group (P < 0.001). No significant increase (0.04%) in sperm count (x 10(6)/ml) was observed in the spermatozoa group. There was a 0.4% increase in motile spermatozoa in the spermatozoa group (P < 0.001). There was a statistically significant decline in normal spermatozoa (3.6%) in the spermatozoa group (P < 0.001). Of the total population, 1364 men had azoospermia (6.0%). The changes observed in the semen parameters analysed in this large population showed no evidence of a deteriorating sperm quality, although a statistically significant decline was observed in the percentage of normal spermatozoa.
authors.affiliation: Laboratorio Investigaciones Seminológicas, Barcelona, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Andolz
authors.forename: M A
authors.initials: MA
authors.lastname: Bielsa
authors.forename: J
authors.initials: J
authors.lastname: Vila
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging; D006801:Humans; D007248:Infertility, Male / Q000473:pathology / Q000503:physiopathology*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009845:Oligospermia / Q000473:pathology / Q000503:physiopathology; D012661:Semen / Q000502:physiology*; D013030:Spain; D013076:Sperm Count; D013081:Sperm Motility