Compared with women, men have a shorter life expectancy. The US Centers for Disease Control and Prevention estimate that women live an average of 5 years longer than men. Now, a new study suggests this disparity may be down to a loss of the Y chromosome in blood cells, prompting men to have a shorter life span and higher mortality from cancer.

The researchers publish the results of their latest findings in the journal Nature Genetics.

As part of a national collaboration between four Swedish universities – known as Sciifelab – scientists from Karolinska Institutet, KTH Royal Institute of Technology, Stockholm University and Uppsala University worked together on the study.

The difference in life span among sexes is not unique to the US; the researchers note that around the world, men have a shorter average life span, and incidence and mortality in cancer is higher in men, compared with women.

Although changes in the DNA of normal cells gather during our lives and have been linked to cancer and diabetes, the researchers say the reasons and risk factors behind the differences in life expectancies have been “largely unknown.”

To further investigate, the team analyzed the DNA in blood samples from a group of more than 1,600 elderly men.