A new study found male-smokers lose more Y-chromosomes than non-smokers and have an increased risk of cancer as they grow older. The new study was published in Science on December 4.
To this day, researchers believed that losing Y chromosomes was only a normal aging process, but earlier this year a study revealed that accelerated loss of Y chromosomes may be linked to increased risk of developing cancerous tumors and death.
The new study adds to these previous findings. Researchers believe that loss of Y chromosomes while aging is also accelerated by smoking.
Dr Lars Forsberg, lead author of the study and researcher at Uppsala University in Sweden, said the new study might explain why so many male smokers develop cancer as compared to female smokers.
The new study also shows that not all men who smoke will lose Y chromosome, just as many non-smokers develop cancer, and many smokers don’t.
“But overall, smoking is associated with loss of Y, and loss of Y is associated with cancer,”
Dr Forsberg also said.
For years, scientists thought that Y chromosomes had no other function than determine male sex. Two-thirds of this chromosome was seen as repetitive and empty DNA code. However, scientists are starting to believe that this chromosome may have multiple roles, besides determining sex. New studies show that it contains a vast amount of genes that haven’t been yet decoded and their purpose remains obscure.
The lead author of the recent study believes that the immune system protection against cancer gets disrupted in cells with no Y chromosome. Other scientists believe that assuming this may be “a pretty big leap” since Y chromosome loss may be just a sign for other genetic damages caused by smoking that remain unknown.
“What we can say from this,” he said, “is that smoking seems to cause a loss of Y, but we’re not really sure yet what the significance is,”
Dr. Martin Bialer, genetics expert that wasn’t part in the study, said.
In the new study, scientists tested blood sample from about 6.000 middle-aged men (smokers and non-smokers). Fifteen percent of the participants aged 70 and beyond had a significant loss of Y chromosome, but male smokers, regardless of age had a two to four times more risk of developing Y loss than non-smokers.
Dr Forsberg had some good news too – he said former smokers had similar test results to non-smokers, and that should give them some extra motivation to stop smoking.