The Grapevine

Smoking Cigarettes Causes Men To Lose Y Chromosomes, While Increasing Their Risk Of Cancer

smoking
A Swedish study finds men who smoke are at a greater risk of losing Y chromosomes. Photo courtesy of Shutterstock.

You’re a guy and you’re a smoker. Better be careful: every drag you take, pardon the pun, may be sabotaging your masculinity… and your life. A new study finds that men who smoke are at greater risk of losing Y chromosomes, the sex-determining chromosome, in their blood cells. This gene mutation was linked, predictably enough, with cancer — yet also with lower survival rates, no matter what caused a man’s death.

“Men who had lost the Y chromosome in a large proportion of their blood cells had a lower survival, irrespective of cause of death,” said Dr. Lars Forsberg, a researcher in the Department of Immunology, Genetics and Pathology at Sweden’s Uppsala University. “We could also detect a correlation between loss of the Y chromosome and risk of cancer mortality.”

The Manly Y

The Y chromosome represents just about two percent of a man’s total DNA. However, though small in terms of proportion, it is not insignificant.  Mutations in genes related to the Y chromosome are the cause of various medical conditions; for instance, men born with an extra Y chromosome have a tall stature yet also developmental and learning problems. That said, not all genes are unique to the Y chromosome, with some present on both the sex chromosomes, the X and the Y. Still, many genes are unique to the Y.

For the study, the team of Swedish researchers led by Dr. Jan P. Dumanski, a genetics professor at Uppsala, sampled blood from three groups of male participants, some beginning the test cycle way back in 1974. The researchers followed the waves of men for 20 years and all passed the age of 48 by their final blood analysis. In particular, the researchers looked at the DNA contained in each man’s blood samples.

The researchers saw striking changes in the DNA of the men who smoked. While the men did not start out with low Y chromosome counts, over time the smokers showed a greater loss of chromosome Y when compared to their non-smoking peers. According to the researchers, those men who smoked the most also experienced the greatest loss of precious Y. The good news? Declines in Y chromosome did not persist among the men who stopped smoking; ex-smokers and men who never smoked seemed to cause a decline in mutation rates. For this reason, the researchers speculate the condition is reversible.

“We believe that analyses of the Y chromosome could in the future become a useful general marker to predict the risk for men to develop cancer,” said Dumanski. Final takeaway? Men who smoke should stop now in order to preserve their lives... and their Y chromosomes, essential to masculinity.

Source: Dumanski JP, Rasi C, Lonn M, et al. Smoking is associated with mosaic loss of chromosome Y. Science. 2014.

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