Male smokers facing infertility is passe now as new study revealed that they lose Y-Chromosome, which is present only in males, substantiating the already established fact that cancer cases are reported more among men than women worldwide.
The study published in Science, encapsulated the research done by Uppsala University researchers that showed a clear link between smoking and loss of the Y chromosome in blood cells. The researchers have previously shown that loss of the Y chromosome is linked to cancer and since only men have the Y chromosome, they are more prone to cancer. Now the researchers also attribute it to the shorter life among men than women.
Smoking causes many diseases, including lung cancer. Epidemiological data show that male smokers have a greater risk of developing cancer outside the respiratory tract than female smokers but the present study, which is the result of an international collaboration, the researchers discovered an association between smoking and genetic damage among men due to their sex difference.
The team, which has earlier demonstrated an association between loss of the Y chromosome in blood and greater risk for cancer, now focused more on any lifestyle or clinical factors that could be linked to loss of the Y chromosome.
“Out of a large number of factors that were studied, such as age, blood pressure, diabetes, alcohol intake and smoking, we found that loss of the Y chromosome in a fraction of the blood cells was more common in smokers than in non-smokers,” said Lars Forsberg, researcher at the Department of Immunology, Genetics and Pathology, Uppsala University, and lead author of the study.
The research further shows that the link between smoking and loss of the Y chromosome was dependent upon the dose, which means loss of the Y chromosome was more common in heavy smokers compared to moderate smokers.
In addition, the link was only valid for current smokers and men who had been smoking previously, but quit, were on par with non-smokers with the same frequency of cells with loss of the Y chromosome. So, the process of loss of Y-Chromosomes is reversible, point out researchers.
“These results indicate that smoking can cause loss of the Y chromosome and that this process might be reversible. We found that the frequency of cells with loss of the Y chromosome was not different among ex-smokers compared to men who had never smoked. This discovery could be very persuasive for motivating smokers to quit,” said Lars Forsberg.
However, it is still unclear how loss of the Y chromosome in blood cells is induced by smoking and causing cancer but one possibility that the researchers cite was that immune cells in blood, that have lost their Y chromosome, have a reduced capacity to fight cancer cells.
“In summary, we have shown that 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. This finding may in part explain why men in general have a shorter life span than women, and why smoking is more dangerous for men,” said Jan Dumanski, professor at the same department of Uppsala University, who has collaborated for the study.
The study is a global collaboration between researchers at Uppsala University, Södertörn University, Karolinska Institutet, the University of Oxford, Broad Institute of MIT and Harvard University, the University of Liverpool, New York University and Stockholm School of Economics. The results have been published on-line in Science Express.