Impact of age, clinical conditions, and lifestyle on routine semen parameters and sperm kinematics.

OBJECTIVE

To assess the impact of aging on routine semen and computer-assisted sperm analysis (CASA) motility parameters according to the current World Health Organization guidelines; and to evaluate the effect of obesity and lifestyle (alcohol consumption, cigarette smoking) in older men's semen.

DESIGN

Blind cross-sectional study.

SETTING

Research laboratory and andrology and reproduction laboratory.

PATIENT(S): A population of 11,706 men.

INTERVENTION(S): None.

MAIN OUTCOME MEASURE(S): Semen analysis: routine (semen volume, sperm concentration and count, motility, vitality, morphology, hypo-osmotic swelling test, round and peroxidase-positive cell concentration) and CASA (straight-line velocity, curvilinear velocity, average path velocity, linearity, straightness, beat cross frequency, wobble, amplitude of lateral head displacement, and mean angular displacement) parameters; and body mass index.

RESULT(S): A negative correlation was found between age and routine semen parameters: volume, sperm count, motility, vitality, total motile spermatozoa and normal-motile spermatozoa, round cell concentration, and hypo-osmotic swelling test values. Several CASA variables (straight-line velocity, curvilinear velocity, average path velocity, beat cross frequency, amplitude of lateral head displacement, and mean angular displacement) were also negatively affected. Using 40 years as a cut-off value, significant differences in most parameters correlated to age. In a selected subpopulation of men unexposed to known fertility-compromising factors, the same evaluations were performed, finding some parameters still decreased. Although obesity exerted a significant deleterious effect on older patients' semen quality, alcohol consumption and cigarette smoking mildly affected it.

CONCLUSION(S): Male aging, with the contribution of unhealthy conditions, are paramount effectors of sperm quality deterioration.