Why is life expectancy longer for women than it is

Bertrand Desjardins, a researcher in the demography department of the University of Montreal, explains.

Men dying sooner than women makes sense biologically: because 105 males are born for every 100 females, it would assure that there are about the same number of men and women at reproductive ages. But even though women showed a longer life expectancy in almost every human society in the last decade of the 20th century, the size of the advantage varied greatly.

For example, in the U.S. male life expectancy was 73.4 years for males and 80.1 years for females, a difference of 6.7 years, whereas in France it was 7.8 years and in the U.K., 5.3 years. The discrepancy was much greater in some countries, with the difference in Russia reaching more than 12 years, but in others, such as India (0.6 year) or Bangladesh (0.1 year), it was much less.

The diversity in worldwide longevity alone indicates that the difference in mortality between the sexes is not purely biological and that there are intervening social factors. Women most probably have a biological advantage that allows them to live longer, but in the past--and in several places, still today--the status and life conditions of women nullified this benefit.

Today, given the general progress in female life conditions, women have not only regained their biological advantage, but have gone much beyond it, both because they tend to engage in fewer behaviors that are bad for health than men do and because they better profit from current advances in health care and living conditions.

The biological advantage that women have is taken as a certainty, because the mortality of males is higher than that of females from the very outset of life: during the first year of life, in the absence of any outside influence which could differentiate mortality between the sexes, male mortality is 25 to 30 percent greater than is female mortality. The genetic advantage of females is evident.

More generally, the genetic difference between the sexes is associated with a better resistance to biological aging. Furthermore, female hormones and the role of women in reproduction have been linked to greater longevity. Estrogen, for example, facilitates the elimination of bad cholesterol and thus may offer some protection against heart disease; testosterone, on the other hand, has been linked to violence and risk taking.

Even though many biological and genetic factors have been identified, their overall effect is impossible to measure, especially given the influence of social factors on mortality. The extraordinary economic and social progress that has occurred since the 18th century has been accompanied by a dramatic reduction of the social differences between men and women and of the burden of motherhood, which had previously negated women's biological advantage. But the recent mortality trends have gone much farther than the mere recovery of an original advantage, creating instead a new advantage of greater magnitude for women.

Observations indicate that the growing excess male mortality in industrial countries could be explained by the rise of so-called "man-made diseases," which are more typically male. These include exposure to the hazards of the workplace in an industrial context, alcoholism, smoking and road accidents, which have indeed increased considerably throughout the 20th century.



It is an accepted fact that women outlive men. Why do YOU think this is so?