Men taking aspirin every day may have double the risk of melanoma, the most serious type of skin cancer, compared to those who are not exposed to daily to the common pain reliever, says a large study involving almost 200,000 patients.
Melanoma is a type of cancer that develops from the pigment-containing cells known as melanocytes. It typically occurs in the skin, but may rarely occur in the mouth, intestines or eye.
The researchers suggested that among the numerous possibilities, one reason men may be more vulnerable could be related to males expressing a lower amount of protective enzymes, like superoxide dismutase and catalase, compared to females, the researcher said.
"These lower levels of protective enzymes suggest that a higher level of resulting oxidative cellular damage in men that might contribute to the possibility of developing melanoma," said study co-author Beatrice Nardone from Northwestern University Feinberg School of Medicine in the US.
Besides acting as a painkiller, aspirin has other uses as well such as reducing the risk of heart attacks and strokes.
"This (the finding) does not mean men should stop aspirin therapy to lower the risk of heart attack," Nardone stressed.
According to the researchers, the result of the study, published in Journal of the American Academy of Dermatology, were surprising because aspirin is often reported to decrease risk of gastric, colon, prostate and breast cancer.
Nardone attributed this to variability of the research methods used in studies that look for associations and risks for cancers.
For the study, researchers collected data comprising almost 200,000 patients who were aspirin-exposed or aspirin-unexposed (control group) with no prior history of melanoma and with a follow-up time of at least five years.
For the aspirin-exposed patient population, the study included only patients who had at least one year of once-daily aspirin exposure at a dose of 81 or 325 mg.
When the groups were separated into men and women, men exposed to aspirin had almost twice the risk for diagnosis of melanoma compared to men in the same population who were not exposed to aspirin.
The findings suggest that men who take daily aspirin may benefit from periodic skin exams by the dermatologist.