Los Angeles, July 7: Men have shorter lives than women because they are more prone to heart disease, claims a new study that found significant differences in life expectancies between the sexes first emerged as recently as the turn of the 20th century.
Across the entire world, women can expect to live longer than men. Researchers wondered why does this occur and was this always the case.
According to the study led by researchers at the University of Southern California Davis School of Gerontology, significant differences in life expectancies between the sexes first emerged as recently as the turn of the 20th century.
As infectious disease prevention, improved diets and other positive health behaviours were adopted by people born during the 1800s and early 1900s, death rates plummeted, but women began reaping the longevity benefits at a much faster rate.
In the wake of this massive but uneven decrease in mortality, a review of global data points to heart disease as the culprit behind most of the excess deaths documented in adult men, said USC University Professor Eileen Crimmins.
"We were surprised at how the divergence in mortality between men and women, which originated as early as 1870, was concentrated in the 50-to-70 age range and faded out sharply after age 80," Crimmins said.
The study examined the life spans of people born between 1800 and 1935 in 13 developed nations. Focusing on mortality in adults over the age of 40, the team found that in individuals born after 1880, female death rates decreased 70 per cent faster than those of males.
Even when the researchers controlled for smoking-related illnesses, cardiovascular disease appeared to still be the cause of the vast majority of excess deaths in adult men over 40 for the same time period.
Surprisingly, smoking accounted for only 30 per cent of the difference in mortality between the sexes after 1890, Crimmins said.
The uneven impact of cardiovascular illness-related deaths on men, especially during middle and early older age, raises the question of whether men and women face different heart disease risks due to inherent biological risks and/or protective factors at different points in their lives, said USC University Professor Caleb Finch. The study appears in the journal PNAS.