Objective: To assess hormone levels, testicular volume, and semen characteristics of fertile men of various age groups.
Patients and methods: The records of 889 men who sought a vasectomy between September 1999 and March 2003 were reviewed. Patients were divided into five groups by age; we evaluated semen volume, sperm concentration, motility, morphology and complex sperm motion variables. Follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone levels and both testicular volumes were compared.
Results: There were no differences among the groups in the levels of LH, testosterone, or right and left testicular volumes. There were differences among the five groups in FSH levels, semen volume, sperm concentration and motility. Normal morphology according to the World Health Organisation criteria was significantly lower in patients aged > 45 years. From a linear regression analysis, semen volume, sperm concentration and motility decreased by 0.01 mL, 2.1%, and 0.27%, respectively, per year, and the FSH level increased by 0.27%.
Conclusions: Sperm concentration and motility decrease and FSH levels increase with age. Normal sperm morphology decreases from 45 years old. Thus, the ageing effect should be considered when proposing standard values for semen characteristics in routine semen analysis.