Across the world, women consistently live longer than men. In the UK, the most recent figures place their average life expectancies at 82.5 and 79.5, respectively.
Read more: The UK's average age has reached an all-time high as population grows at an above-average rate
The reason for the difference is not fully understood, but new research from the University of South Carolina suggests the main cause is a lower risk of developing heart disease among women.
They looked at how death rates changed in 13 developed countries at the end of the 1800s and start of the 1900s, when improvements to healthcare and diet caused death rates to plummet.
They found that although everyone benefited from these improvements, it was women that experienced the biggest increase in life expectancy – for individuals born after 1880, female death rates decreased 70 per cent faster than those of males.
Read more: Women's life expectancy has fallen for the first time since 1995 – and it could be because they're taking up traditionally male habits
Even when the researchers controlled for smoking-related illnesses, cardiovascular disease appeared to be the number one health problem holding men back from experiencing the fast rise in life expectancy, as it caused the vast majority of excess deaths in men over 40.
Smoking accounted for just 30 per cent of the difference in mortality between the sexes after 1890, despite men making up by far the majority of smokers at the time – this was less than the researchers were expecting. The results are published in the journal the Proceedings of the National Academy of Sciences.
Nature versus nurture
Whether men's poorer cardiovascular health is the result of genetics or environmental factors is not known. Caleb Finch, lead researcher in the study, said more work was needed to determine that:
Further study could include analysis of diet and exercise activity differences between countries, deeper examination of genetics and biological vulnerability between sexes at the cell level, and the relationship of these findings to brain health at later ages.