Why do women outlive men?

Around the world, women live longer than men [Ortiz-Ospina & Beltekian 2018]. This is true not only for humans, but also for many other mammalian species [Xirocostas et al. 2020]. The higher life expectancy of women is often attributed to the fact that women generally eat healthier and pay more attention to their health. On average, women visit the doctor earlier and more often than men, generally drink less alcohol, use less tobacco and pay more attention to a healthy diet [Griswold et al. 2018, Oksuzyan et al. 2014]. Life expectancy statistics also include suicide, which is significantly more common in men than in women [Kiely et al. 2019, Miranda-Mendizabal et al. 2019]. However, there may also be a genetic component that makes women live longer. The advantage for women may be the double X chromosome [Xirocostas et al. 2020]. While women have two X chromosomes, men have one X chromosome and one Y chromosome. Important genetic information on the X chromosome is therefore duplicated in women and can compensate for possible gene mutations and defects on the other X chromosome.

This is not the case in men and is responsible, for example, for the colour blindness that is much more common in men. A key factor in ageing may be that the X chromosome also contains gene segments that influence the body's immune system [Libert et al. 2010]. If these gene segments are defective in men, they cannot be compensated for by a second, defect-free X chromosome. In addition to the different sex chromosomes, the influence of sex-specific hormones on the ageing process is also being discussed. For example, the hormone testosterone has been linked to risk-taking behaviour and an increased incidence of cardiovascular disease in men [Roberts et al. 2004, Stanton et al. 2011].