A recent academic study has shown that under extreme conditions such as famines, epidemics and enslavement, women are able to survive for longer than men. Across modern populations, women outlive men in almost all instances, with life expectancy for English women being 83.1 years, compared to 79.5 years for men (the figure for Scotland is 81.2 years for women and 77.1 years for men).
Now, academics from the Southern University of Denmark have looked at data from seven historic cases when populations were exposed to extreme hardship, in order to gain new insights into the gender mortality gap. Case studies included the Irish famine of 1845-1849, the Iceland measles epidemics of 1846 and 1882, and the experiences of freed Liberian slaves returning to Africa from the US in the early 19th century, where they encountered a very different disease climate which killed many. These situations saw dramatic decreases in life expectancy. During the 1882 Iceland measles epidemic, for example, life expectancy dropped from 43.99 to 18.83 years for females and from 37.62 to just 16.76 years for males.
The researchers found that, in all the populations, women had lower mortality across almost all ages, and with one exception, women lived longer on average than men.
The study noted that gender differences in infant mortality “contributed the most” to the gender gap in life expectancy, indicating, “that newborn girls were able to survive extreme mortality hazards better than newborn boys”. Based on these findings, the academics concluded, “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 behavioural and social differences may be minimal or favour males.”
They did however note that “Our findings also indicate that the female advantage differs across environments and is modulated by social factors.” The academics referred to existing research that suggests hormonal differences might further explain the gender mortality gap. For example, oestrogens, found in larger quantities in women, have anti-inflammatory effects, whereas testosterone, found in larger amounts in men, may actually suppress the immune system.
The new study’s lead author, Professor Virginia Zarulli, wrote in the journal PNAS: “The conditions experienced by the people in the analysed populations were horrific. Even though the crises reduced the female survival advantage in life expectancy, women still survived better than men.