- According to the authors of new research, their study is the first to use the ‘outsurvival statistic’ to quantify the probability of men living longer than women across multiple populations over time.
- Their analysis of hundreds of populations over 200 years showed that a fraction of men—between one and two men out of four—outlive a randomly paired woman.
- The probability of men outliving women also varies depending on their marital status and educational attainment, the study found.
Early in school, it is common for students to learn that women tend to live longer than men. While this bit of trivia is common knowledge, it’s probably an overly simplistic portrait of male and female lifespans, according to a new study by researchers at the University of Southern Denmark.
Traditionally, scholars have determined that women live longer than men by comparing life expectancy, a statistical measure of the average time an individual or group of individuals are expected to live. For this study, the researchers employed the outsurvival statistic, which measures the probability that an individual from a population with low life expectancy will live longer than an individual from a population with a high life expectancy.
“We think that the metric that we developed, this outsurvival statistic, is better than the alternative metrics in several key aspects,” Ilya Kashnitsky, assistant professor at the Interdisciplinary Centre on Population Dynamics at the University of Southern Denmark and a co-author of the study, told Medical News Today.
Published in the open-access journal BMJ Open, the study reports that since 1850, between 25% and 50% of men, who lived at all points in time and across all populations, outlived women.
“We can do it any number of times here,” Kashnitsky said. “Like take 1,000 random or 10,000 random men and then, independently, take a random woman from this population. Compare. Look who lives longer. And when we do these comparisons… if we aggregate on average there [is a] 40% chance that men will live longer than women.”
For the study, the researchers studied sex differences in mortality in 199 populations from every continent over 200 years. They found that despite large differences in life expectancy, there are substantial overlaps between males’ and females’ lifespan distributions.
“You can often read in the papers… ‘Well, women live longer than men’,” Kashnitsky told MNT. “And then the nuance that, actually, these distributions overlap a lot is usually lost.”
The majority of people, including many individuals working in medical fields or in public health, don’t understand statistics, Hamilton Lombard, a demographer at the University of Virginia’s Weldon Cooper Center for Public Service, told MNT.
For example, Lombard pointed out that people think that because the life expectancy in 1700 was 30 that it was very rare, at that time, to ever see an old person.
“That’s not true at all,” he said. “Probably 80% of all the deaths were happening for people under the age of two. If you made it out to 18, your odds of living to be 80 weren’t very different from today. There were lots of 80-year-olds back then.”
Lombard said it’s “fantastic” that the study illustrates that men have a high probability of outliving women. He added, though, that ideally, the general public would also understand variation in life expectancy.
“If somebody did statistics and can remember standard deviation they would get that concept really quickly,” Lombard said, adding: “But I think most people don’t ever take statistics.”
In their study, the researchers point out that men are more prone to accidents and homicides in their 20s and 30s. Men also tend to smoke and drink more, leading to higher cancer prevalence and death in their 60s.
“So, the differences of ages of death within males are much, much huger than the differences between males on average, and females on average,” Kashnitsky said.
The study points out that only a few times in history among specific populations did more than 50% of men outlive women.
Those times were in Iceland in 1891, in Jordan between 1950 and 1954, in Iran between 1950 and 1964, in Iraq between 1960 and 1969, in Bangladesh, India, and the Maldives before 1985, and in Bhutan between 1995 and 2010.
A complex combination of biological, environmental, and behavioral factors determine the length of an individual’s lifespan, according to the researchers.
Marital status plays a role. With couples, the researchers explain in the study, social ties impact health and longevity patterns. In the United States between the years 2015 to 2019, the probability of outliving women for married men was 39%. For single men, the probability was 37%.
Educational attainment also matters. The probability of men to outlive women was 43% for men with a university degree and 39% for men who did not have a high school diploma.
“If a man has a college degree, they’re more likely to outlive a woman with just a high school degree and even more likely to outlive a woman without a high school degree,” Lombard told MNT.
By pointing this out, the study is telling readers it’s not cut and dry that women outlive men, according to Lombard. “It really depends on variables.”
The study does a good job of illustrating, according to Lombard, the fact that the typical lifespans for men and women have changed over time. “It’s not been static,” he said.
Today, it’s common to see more women living in nursing homes than me, but Lombard predicts that won’t always be the case.
The gap in life expectancy between men and women was wider 30 to 40 years ago. That’s due to differences in behavior like smoking and drinking and that “with better healthcare, particularly for children, [women] started having longer lives,” Lombard said. “[M]en didn’t see a similar improvement at the same time, so that caused the gap to get bigger.”
Today, in most developed countries, Kashnitsky explained: “People are dying at more similar ages.”