DURHAM, N.C. — Across the globe, women typically have a longer lifespan than men. There are many theories as to why, but a recent study suggested that women may deal with hardship better than men and are more likely to survive extreme crises.
A research team comprised of Duke University and University of Southern Denmark scientists analyzed mortality data going back 250 years to arrive at their conclusions.
They found that, perhaps surprisingly, the life expectancy gap in times of great stress and hardship showed an advantage for females as early as infancy. In other words, they say female infants are hardier and more resilient than males, particularly during trying times.
The authors focused on seven populations in which the life expectancy was 20 years or less for one or both sexes. Among those populations were African slaves working in the United States and Trinidad in the early 1800s; famine victims in Sweden, Ireland, and the Ukraine in the 18th, 19th, and 20th centuries and Icelanders suffering from the measles epidemics of 1846 and 1882.
In each of these horrible historical periods in which children were dying exceptionally young, bringing life expectancy rates down to miserable levels, women still lived longer than men by six months to as much as four years on average. For example, girls born during the Ukrainian famine that struck in 1933 lived 10.85 years on average, while boys lived 7.3 years — a 50% difference.
The results of this new research introduces new notions that the gap between the life expectancy of girls and boys is not entirely because of behavioral and social differences between the sexes, such as risk-taking and violence. Instead, there may be something to the notion that biology holds the key to women being more resilient. The authors point to estrogen as an example because of the hormone’s ability to boost women’s immune system.
“The hypothesis that the survival advantage of women has fundamental biological underpinnings is supported by the fact that under very harsh conditions females survive better than males even at infant ages when behavioral and social differences may be minimal or favor males,” the researchers write.
The study was published January 8, 2018 in Proceedings of the National Academy of Sciences.