ESPE Yearbook of Paediatric Endocrinology

To read the full abstract: Proc Natl Acad Sci U S A 2018;115:E832-E840

Women live longer than men in nearly all modern populations. They can expect to live longer than men almost anywhere in the world. This pervasive inequality has intrigued researchers for decades, and many conclude that the gap has biological foundations, which are modulated by social and environmental conditions.

Here, Zarulli et al. studied data on survival of male and female Freed Liberian slaves between 1820-1843; plantations slaves in Trinidad in the early 19th century; the Ukrainian, Irish and Swedish famines in 1933, 1845–1849, and 1772–1773, respectively; and the Icelandic epidemics in 1846 and 1882. In all of these settings, with the partial exception of the Trinidad slaves (in the case of the lower-bound scenario), females lived longer than males. They cite the fact that under very harsh conditions females survive better than males even as infants, when behavioral and social differences may be minimal or favor males, lending support to a biological explanation for the female survival advantage, which may subsequently be influenced by socially and environmentally determined risks, opportunities, and resources. Consistent with a biological basis, females live longer than males in most monkeys and apes for which data are available, in both captive and wild populations. The sexual dimorphism in resilience becomes smaller later in life, when estrogens disappear, which may suggest a hormonal basis, which could act on health (e.g. protection from cardiovascular disease) or behaviors (e.g. women take fewer risks than men). There are different ways of describing the same coin; a previous study found that an increased men’s mortality in a list of specific entities is the reason, rather than a female survival advantage. But whatever the epidemiology, the mechanism must lie with the main sex-specific factors, the X- and Y-chromosomes and sex hormones.