Do women or men live longer? In almost every population across the world, it’s women, according to a new report.
Researchers from Duke University and other institutions in Denmark and Germany recently conducted an experiment to determine what biological and social factors influence this gender gap.
To do so, they examined mortality data that went back nearly 250 years and spanned seven populations where the life expectancy for one or both sexes was 20 years or less. The individuals, which included working and former slaves, had died early by either famine, disease or other misfortunes.
After analyzing the results, they found that women outlived men even when the mortality rate was very high for both sexes. In fact, women lived longer than men by between six months and almost four years on average. And in some countries, it was more than a decade.
After they categorized their findings by age group, they also discovered infant mortality rates are lower among women. “Newborn girls are hardier than newborn boys,” the authors wrote.
While the scientists noted the gender gap couldn’t be fully explained by behavioral or social differences between sexes, they believe biological factors could play a key role.
“The female advantage in times of crisis may be largely due to biological factors such as genetics or hormones,” they said. “Estrogens, for example, have been shown to enhance the body’s immune defenses against infectious disease. ... Our results add another piece to the puzzle of gender differences in survival.”
Want to learn more about the findings? Take a look at the full analysis, published in the Proceeding of the National Academy of Sciences.