Scientists have uncovered fresh clues that could explain why men typically don't live as long as women.
Research suggests this is linked to the loss of the Y chromosome, which can cause the heart muscle to scar and can lead to deadly heart failure.
An estimated 40% of 70-year-olds suffer from the loss of this male sex chromosome, but they could benefit from an existing drug that targets dangerous tissue scarring.
Chromosomes are bundles of DNA in each cell which come in pairs. Women have two X chromosomes while men have an X and a Y chromosome.
Professor Kenneth Walsh, from the University of Virginia, said: "Particularly past age 60, men die more rapidly than women. It's as if they biologically age more quickly."
He added: "This new research provides clues as to why men have shorter lifespans than women."
Pirfenidone may help counteract the harmful effects of the chromosome loss, University of Virginia (UVA) researcher Kenneth Walsh said.
Many men begin to lose their Y chromosome in a fraction of cells as they age - something which appears to be particularly true for smokers.
Scientists previously found men who suffer Y chromosome loss are more likely to die at a younger age and suffer age-related conditions such as Alzheimer's.
The new research is believed to be the first hard evidence the chromosome loss directly causes harmful effects to men's health.
Researchers used gene-editing technology to develop a special mouse model to better understand the effects of Y chromosome loss in the blood.
They found the loss accelerated age-related diseases and made the mice more prone to heart scarring and led to earlier death.
The researchers also looked at the effects of Y chromosome loss in human men, conducting three analyses of data compiled from the UK Biobank study. They found Y chromosome loss was associated with cardiovascular disease and heart failure.
As chromosome loss increased, so did the risk of death, the researchers found.
They said their findings suggest targeting the effects of Y chromosome loss could help men live longer, healthier lives.
The findings are published in the Science journal.