Gender gap in longevity and disability in older persons.

Today, a woman has an excellent chance of surviving well into her 80s and, for those who survive to age 85 years, the remaining average life expectancy is an additional 6 years. Therefore, most women who reach age 85 can expect to pass age 90 (1). Life expectancy varies throughout the lifespan. The gap between men and women is actually largest at younger ages and gets smaller with increasing age (figure 1). Nevertheless, at all ages, women have a better survival than do men. At birth, the gap is about 6 years; at age 65, it decreases to about 3 years; and at age 75, it is even lower, at about 2 years (1). The gender gap in longevity has changed over time and varies across countries. Stages have been described that relate gender differences in longevity to societal development (2). In developing societies (stage 1), life expectancy in women is limited by high maternal mortality, so that the gender gap between men and women tends to be smaller. Stage 2 societies have had improvements in maternal and infant mortality, resulting in an increase in the gender gap that substantially favors women. Currently, the developed countries are entering a third stage, in which the life expectancy for women is so high that it may be near its maximum, and now the continued improvements in life expectancy are relatively greater for men than for women. Thus, in developed countries such as the United States, Canada, and the countries of Western Europe, the gender