MedWire News: Results from a prospective study have confirmed that cigarette smoking reduces sperm motility, decreases the antioxidant capacity of the semen, and increases the risk forleukocytospermia.

"Numerous investigations have been conducted on the relationship between cigarette smoking and male infertility; however, the exact molecular mechanisms are not well understood," write Fabio FirmbachPasqualotto and colleagues from the University of Caxias do Sul in Brazil.

Accordingly, the researchers analyzed the semen of 112 infertile men and 10 fertile volunteers.

Comparisons revealed that concentrations of the antioxidants superoxide dismutase and catalase were significantly lower in semen from infertile than fertile men, and that semen levels of superoxide dismutase significantly and negatively correlated with cigarette smoking.

In addition, semen levels of superoxide dismutase were positively linked to sperm number and negatively related to leukocytospermia, which also inversely correlated with sperm motility.

"We can conclude that decreased antioxidant enzyme levels are associated with male infertility, and that the detrimental effects of cigarette smoking on sperm motility and antioxidant levels may be a possible reason for infertility in men who smoke cigarettes," summarize the investigators.

They add: "Given the potential adverse effects of low antioxidant levels on fertility, physicians should advise infertile patients who smoke cigarettes to quit smoking."

Journal abstract