decline of semen quality and increase of leukocytes with cigarette smoking in infertile men

background: previous researches about the effect of smoking on semen quality are contradictory, and the mechanism behind the harmful effect of smoking on semen quality still remains unclear until today. objective: the objectives of this study are evaluation of the relationship between smoking and fertility, investigation of the effects of cigarette smoking on sperm parameters and detection of presence of leukocytes within the semen of idiopathic infertile men from northeastern china. materials and methods: a retrospective study of 1512 infertile patients who visited affiliated hospitals of jilin university from 2007-2010 were enrolled in this study. patients were assigned into one non-smoking and one smoking group which was divided into mild, moderate and heavy subgroups. sperm parameters (including leukocytes) and sperm morphology analysis were performed using standard techniques. results: compared with non-smokers, smokers had a significant decrease in semen volumes (p=0.006), rapid progressive motility (p=0.002) and sperm viability (p=0.019); moreover, smokers had a significant increase in the levels of immotile sperms (p=0.005) and semen leukocytes (p=0.002); ph and sperm concentration were not statistically significant (p=0.789 and p=0.297 respectively). sperm motion parameters were all lower in the smokers except for beat-cross frequency (hz) (bcf). further, the percentage of normal morphology sperm was decreased significantly in smokers (p=0.003), the sperm morphology was worse with increasing degree of smoking. conclusion: these findings suggest that smoking leads to a significant decline in semen quality and higher levels of leukocytes, thus smoking may affects the fertilization efficiency.