Objective: To study the contribution of smoking and alcohol consumption to semen quality.
Design: Retrospective analysis.
Setting: University-based fertility clinic.
Patients and methods: Smoking and alcohol consumption were investigated in a control group (68) and in a group of 47 subjects with defined poor semen quality (PSQ). The control group was composed of subjects whose semen showed a greater than 60% morphological normality, a greater than 60% motility with a linear progression, and a density of greater than 20 million spermatozoa/mL. The group with PSQ was composed of subjects whose semen showed a less than 30% morphological normality, less than 60% motility, characterized by slow, weak motility, and a density of less than 20 million spermatozoa/mL. Medical dossiers were studied regarding the life style of the subjects.
Results: The distribution of heavy smokers and light smokers did not differ statistically between the groups. There appeared to be a higher, but statistically insignificant, proportion of heavy smokers in the PSQ group (50%) compared to the control group (32.3%; P < .1); nor were significant differences found between cases and controls with respect to alcohol consumption pattern. In the PSQ group, a comparison of the semen characteristics of the daily drinkers with those of all the other subfertile patients showed no statistical difference concerning semen volume (4.1 +/- 1.9 vs. 3.3 +/- 1.3 mL; P > .1), sperm density (10.6 +/- 7.8 vs. 8.9 +/- 5.8 million spermatozoa/mL; P > or = .1), and percentage of motile spermatozoa (27.0 +/- 15.1 vs. 25.5 +/- 16.1%; P > .1). However, a lower percentage of normal sperm morphology was observed in the daily-drinker group (17.6 +/- 7.2% vs. 23.0 +/- 6.5% for the other subfertile patients; P < .05).
Conclusion: Factors such as smoking and alcohol consumption do not seem to play a pivotal role in the etiology of poor semen quality, but a pattern of excessive alcohol consumption may decrease further an already low percentage of sperm with normal morphology.