Smoking May Harm Sperm, Male Fertility
Results Seen in Small Study Funded by Cigarette Company
Oct. 17, 2005 -- Smoking may hamper a man's fertility, according to a small study funded by cigarette company Philip Morris.
Scientists at the University of Buffalo compared sperm from screened sperm donors to sperm from 18 male smokers. In lab tests, the smokers' sperm was less likely to bind tightly to an egg -- a necessary step for fertilization.
The results were presented in Montreal at the American Society of Reproductive Medicine's annual meeting.
"Specialized testing clearly reveals a significant drop in fertility potential for men who are heavy tobacco smokers," says researcher Lani Burkman, PhD, in a news release.
Men who smoke also "should be aware that smoking can damage their sperm DNA, passing on faulty DNA to their baby. Concerned smokers should quit or be tested in a local andrology laboratory," says Burkman.
Burkman is an assistant professor of urology at the University of Buffalo's medical school. He is also an associate professor and head of the andrology section of the university's gynecology and obstetrics department.
Study of Smokers
The smokers in the study all smoked at least four cigarettes a day for two years or more. On average, they had smoked for more than 15 years.
In a lab test, the sperm from each smoker was exposed to half of an egg for two or three hours. The test was also done with the donors' sperm, using the other halves of the same eggs.
To pass the test, at least 65% of a man's sperm had to bind tightly to the egg's outer layer.
The sperm from 12 smokers (two-thirds of the smokers) failed. Their sperm wasn't totally infertile but showed only one-quarter of normal fertilizing capacity, the researchers note.
"Most of the failed cases (nine out of 12) demonstrated a severe loss in fertilizing capacity," write Burkman and colleagues. Sperm from the other smokers showed normal function.