Why Women Live Longer

It isn't natural—lower rates of smoking, childbirth, and access to modern healthcare all play a part.

Misao Okawa
World's oldest living person, 115-year-old Misao Okawa, receives her certification from a Guinness World Records official in Osaka, Japan (Reuters/Kyodo)

Salustiano Sanchez-Blazquez became the world’s oldest man last month, at age 112, the Associated Press reported last week. But the oldest woman is 115. As in most sports, survival statistics are sex segregated to give the weaker sex a chance at being number one — 87 percent of a (Wikipedia’s) list of the oldest people since 1955 are women.

There are many causes of women’s longevity, some apparently biological (such as their more resilient immune systems) and some more man-made (such as lower rates of accidental, homicidal, or suicidal death). But the overall survival advantage is an outcome of social dynamics.

Life expectancy stats
(Centers for Disease Control)

In the United States, women’s advantage in life expectancy at birth is just less than five years, but it was almost eight years in the 1970s. Demographers have determined that the major driver of the 20th century trend was smoking (there is a similar pattern in much of Europe).

News reports didn’t mention whether Sanchez-Blazquez smoked, but more than 80 percent of American men born in 1901 did by the time they were in their thirties, which accounts for the early deaths of millions of men into the 1970s (in the 1950s Americans consumed about 12 pounds of tobacco per person annually, three times current levels). In contrast, young women’s smoking rates never passed 55 percent, and their peak was later, in the 1970s. Since 1965 smoking rates have fallen by more than half, and the gender gap has dropped by more than two-thirds, so women’s survival advantage may narrow further.

Smoking rates by sex
(National Health Interview Survey)

The global advantage

Smoking is a major factor globally, and many countries could be going through what the U.S. did in the last century. The World Health Organization reports that smoking is more common for men than for women in every country except Austria, and in many countries the difference is huge.

Smoking rates by sex
(World Health Organization)

Women have a survival advantage in 204 out of 210 countries, with average lives 4.6 years longer than men’s, as shown below in the figure on the left. And this is not just from men dying younger due to war, violence, or accidents. The figure on the right shows life expectancy for those who survive to age 60, and here too the female advantage is nearly universal. No one suggests this is all due to smoking, of course. But men’s higher smoking rates are relatively recent in many countries, so we might see a widening gap in the next few decades.

Life expectancy across countries
(United Nations Statistics Division)

In the U.S., are we returning to a “natural” female survival advantage now that smoking differences are narrowing? Historically, women’s advantage only emerged once social development made a few changes to the ground rules: fewer babies, fewer deaths in childbirth and basic access to modern healthcare and sanitation.

If you look back 10,000 years, it appears that women in the hunter-gatherer bands of southwest Asia had lower mortality rates than men did. But just a few thousand years later, after they settled down into agricultural food production, the situation reversed and women’s mortality rate was higher—probably because they started having more children, spaced more closely together. So which condition was natural? Since then, the pre-modern historical record offers little consistency. In medieval Japan women lived longer than men, but the opposite was true in medieval Croatia and 18th century rural Finland. It is not until the last century or two that universal female advantage emerged.

Way too many women around the world still die in childbirth, but it’s a much smaller factor in overall survival than it once was, even in the places with the highest childbirth death rates. That’s because women have fewer babies, and live much longer after their childbearing years, which dilutes the effect of maternal mortality on overall survival. In the U.S., our maternal mortality is a shameful 17 per 100,000 births—higher than all but one Western European country (Cyprus), and more than twice their average. But even here, dying in childbirth accounts for only 1.4 percent of women’s deaths from ages 15 to 44, an age range that only accounts for 4 percent of all female deaths. So it’s just not driving the sex difference in survival.

I suspect that even if we eliminated smoking, war, murder, and maternal mortality, women would live a few years longer than men, on average. But that doesn’t make it natural.