Rava is an online news portal providing recent news, editorials, opinions and advice on day to day happenings in Pakistan.
Women live longer than men in almost all modern populations. That is a fact.
But scientists still can not explain very well why.
Some studies have tried to investigate the biological origins of that advantage. Others have highlighted the importance of social factors.
Now, research from the Danish university Southern University has just confirmed that women have an “omnipresent” survival advantage, even in circumstances in which the overall mortality is extraordinarily high.
Their findings were recently published in the American scientific journal PNAS ( Proceedings of the National Academy of Sciences ).
Advantage even in famines and epidemics
The academics investigated the differences in survival between men and women in seven populations that lived under extreme conditions, such as famines, epidemics and slavery.
They analyzed the differences in mortality during:
- famines in Ukraine (in the 1930s), Sweden (1770) and Ireland (1845)
- epidemics in Iceland (1840 and 1880) and between slave populations in plantations in Trinidad in the early nineteenth century and freed American slaves who returned to Liberia circa 1820, only to find a very different epidemiological environment that ended the lives of many .
During the measles epidemic of 1882, for example, life expectancy dropped from 43 to 18 for women and 37 to 16 for men.
The researchers found that women survived more than men : in all populations they had a lower mortality rate in almost all age groups, and, with the exception of one slave population, they lived on average more than men.
Differences already in neonates
Interestingly, the difference in mortality between men and women was already manifested among babies: in extreme conditions girls survived more than boys, at early ages in which social and behavioral differences may be minimal or may even be favorable for the men.
These results agree with the hypothesis that women have a biological survival advantage, although this advantage may also interact with environmental factors.
“Our findings also indicate that the female advantage differs in different environments and is modulated by social factors,” they clarify in the study.
What is that advantage?
But the scientific community still does not know how to explain what concrete biological aspects are behind these gender differences in mortality rates.
In this study, the researchers refer to previous analyzes that suggest that hormonal differences between men and women can play a role.
For example, estrogens, which are hormones that women have in abundance, have an anti-inflammatory effect, while testosterone, typical of men, can suppress the immune system.
In any case, according to the academician who led the study, Virginia Zarulli, “the conditions experienced by the people in the analyzed populations were horrible.” Although the crises reduced the survival advantage in terms of life expectancy, women survived better than the men”.
“Even when mortality was very high, women lived longer.”