Smoking Could Cause Loss of Y Chromosome

Researchers at Uppsala University in Sweden believe they have found a link between smoking and the loss of the Y chromosome in men, though exactly what causes that loss is unclear. The findings, published in Science on Thursday, present yet another compelling reason to quit smoking. In light of a previous study, which found an association between Y chromosome loss in blood cells and a higher risk for cancer, more smokers may leave the pack behind.

The studies, led by professor Lars Forsberg, could help researchers to understand why male smokers are at a higher risk for developing cancer outside the respiratory tract than women who smoke, as well as why men are at a higher risk of dying from gender non-specific cancers. The first study, published in Nature, found that men with a significant loss of Y chromosomes experienced a median survival time 5.5 years less than men with no significant loss. The findings, according to the study, suggest that Y chromosomes may have an impact beyond gender determination.

For the most recent study, researchers collected data from 6,000 men and assessed factors such as diabetes, age, alcohol intake, blood pressure and smoking habits to determine if any of those factors could be linked to Y chromosome loss in their blood cells. The only two factors that seemed to be associated with the loss were age and smoking, and the amount the men smoked factored heavily into the rates of loss. Heavy smokers presented a higher instance of loss than moderate smokers, and men who had quit smoking showed the same levels as men who had never smoked at all. Smokers were 2.4 to 4.3 times more likely to present a loss of Y chromosomes than non-smokers.

For the study, researchers took advantage of data which are being used for three ongoing, long-term studies on possible associations between traits—such as lifestyle and behavior— and disease. The recent observation has led the research team to found the Cancer Risk Assessment from loss of chromosome Y (CRAY) Innovation startup, in the hopes of developing a diagnostic test to assess men’s cancer risk based on levels of Y chromosome loss in their blood cells, reports Science.

Researchers still do not understand what the correlation between the loss and the heightened risk for cancer might be, but they hypothesize that the deficiency may favor specific blood cells known to fight cancer. Without a Y chromosome, those blood cells are unable to fight off the cancer, which allows it to spread. The team plans to conduct multiple follow-up studies to test that hypothesis. The researchers also speculate that smoking may cause damage to all DNA, but that the small, mutation-prone Y chromosome is simply more susceptible. Forsberg believes the results of the study may convince more smokers to quit, knowing the loss of the chromosome is reversible.

A study published in 2011 in Cancer Epidemiology, Biomarkers and Prevention analyzed data from the National Cancer Institute—which has been collecting cancer data since the 1970s—reported a higher likelihood of death from cancer among men than women. According to the study, lip cancer saw the largest gap in cancer-related mortality between the sexes, accounting for 5.51 deaths among men for every one among women.

By Sree Aatmaa Khalsa

Medical News Today
Cancer Epidemiology Biomarkers and Prevention

Photo by: Molly – Flickr License

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