Male smokers are three times more likely than non-smoking men to lose their Y chromosomes, according to research that may explain why men develop and die from many cancers at disproportionate rates compared to women.
In a study in the journal Science, researchers at Sweden's Uppsala University found that Y chromosomes, which are important for sex determination and sperm production, more often disappear from blood cells of smokers than those of men who have never smoked or of men who have kicked the habit.
Since only men have Y chromosomes, the finding offers a possible answer to why smoking is a greater risk factor for cancer among men than women.
"There is a correlation between a common and avoidable risk factor, that is smoking, and the most common human mutation — loss of the Y chromosome," said Jan Dumanski, an Uppsala professor who worked on the study. "This ... may in part explain why men in general have a shorter life span than women and why smoking is more dangerous for men."