Women live longer than men even during severe famines and epidemics

Abstract

Women in almost all modern populations live longer than men. Research to date provides evidence for both biological and social factors influencing this gender gap. Conditions when both men and women experience extremely high levels of mortality risk are unexplored sources of information. We investigate the survival of both sexes in seven populations under extreme conditions from famines, epidemics, and slavery. Women survived better than men: In all populations, they had lower mortality across almost all ages, and, with the exception of one slave population, they lived longer on average than men. 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. Our results confirm the ubiquity of a female survival advantage even when mortality is extraordinarily high. 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. Our findings also indicate that the female advantage differs across environments and is modulated by social factors.

Keywords: epidemics; famines; gender; mortality; survival.

Fig. 1.

Survival curves (shaded areas), life expectancies (solid vertical lines), and ages at which only 5% of a synthetic same-sex cohort would still be alive (dashed vertical lines) for seven high-mortality populations. For Trinidad, dashed survival curves and vertical lines with asterisks represent estimated upper bounds. Source: authors' calculations based on published data from ref. for Liberia, from ref. for Trinidad, from ref. for Ukraine, from ref. for Ireland, and from the Human Mortality Database (www.mortality.org) for Sweden and Iceland.

Fig. 2.

Age decomposition of the differences in life expectancies between males and females for the eight high-mortality populations. Light blue bars for Trinidad represent the decomposition of the upper-bound life expectancy values. See Table S1.

Fig. 3.

Male:female mortality ratios and differences over age for seven high-mortality populations. Gray lines represent the unsmoothed data, blue lines represent the smoothed data [obtained with the R function stat_smooth (100)], and the gray shaded areas represent the SEs of the smoothing. The dashed lines for Trinidad represent the smoothed upper-bound values. Source: authors' calculations based on published data from ref. for Liberia, from ref. for Trinidad, from ref. for Ukraine, from ref. for Ireland, and from the Human Mortality Database (www.mortality.org) for Sweden and Iceland.