Even if general appeals to one's health aren't enough to convince people to quit smoking, perhaps this new research out of Sweden will give men some pause. An Uppsala University study published yesterday in Science says that male smokers are, on average, three times more likely to lose Y chromosomes as their nonsmoking counterparts, Reuters reports. The study also found that the more men smoked, the more Y chromosomes they lost, LiveScience reports. "The cells that lose the Y chromosome … don't die," says study co-author Lars Forsberg. "But we think that they … have a disrupted biological function." Specifically, that disrupted function may mean that blood cells missing the Y's can't fight off disease, he explains—and because only men have Y chromosomes, that cell-weakening could be the link to men's higher cancer rates.
The study looked at blood pressure, as well as drinking, exercising, and smoking habits, and collected blood samples of 6,000 men taking part in three separate studies in Sweden. Forsberg and his team had previously linked the loss of the Y chromosomes in blood to shorter life spans and a jump in the rate of non-blood-related cancers, so they controlled for age in this study to isolate other factors that might lead to this loss: Only smoking had a correlation. There's good news to be found from the study, though: Forsberg says that some study participants who eventually kicked the habit ended up recouping their lost Y chromosomes, suggesting the chromosome loss may be reversible. "This discovery could be very persuasive for motivating smokers to quit," he says. (Meanwhile, women have a higher risk of heart disease from smoking than men.)