New research may have put paid to the age-old trope that women outlive men, with the latest findings suggesting there's a high probability that men typically live longer - especially those who are married and have a degree.
The statistical analysis, conducted by a team of researchers at Denmark's Syddansk Universitet, spanned more than 200 years across all continents of the globe and was published in the journal BMJ Open.
Over the last two centuries, between 25 percent and 50 percent of men have outlived women, challenging the received wisdom that men simply don't live as long as their counterparts, said the scientists.
The myth of women always outliving men is in part due to the use of 'life expectancy', which is an average, the researchers said. Large differences in life expectancy can sometimes mask substantial overlaps in lifespan between the sexes.
Women's 'survival advantage' has been observed over time across many different populations. However, sex differences in survival are often identified by comparing life expectancy, which summarises the average length of life, rather than years lived - and this has been interpreted as 'men do not live as long as women', the researchers explained.
The team wanted to quantify the probability that males outlive females over time and across populations, exploring the impact of changes in life expectancy and variations in lifespan between the sexes.
They used a particular statistical approach - the 'outsurvival' statistic - to study differences in deaths between the sexes in 199 populations from every continent over a period of 200 years. This statistic measures the probability that a person from a population with a high death rate will outlive someone from a population with a low death rate. Additionally, the researchers compared the probability of men outliving women by education level and marital status, using national US statistics on deaths and population counts.
The analysis showed that since 1850, the probability of males outliving females has, at all points in time and across all populations, varied between 25 percent and 50 percent - with only a few values above 50 percent in different countries at different times.
These were Iceland in 1891; Jordan in 1950–54; Iran in 1950–64, Iraq in 1960–69; before 1985 in Bangladesh, India, and the Maldives; and between 1995 and 2010 in Bhutan.
In other words, the data showed that between one and two of every four men have outlived women for the past 200 years, challenging the age-old notion that men simply don't live as long as women.
In developed countries, the probability of males outliving females fell until the 1970s, after which it gradually increased in all populations. The rise and fall in differences in life expectancy were mainly attributed to smoking and other behavioural differences.
The probability of males living longer than females is generally higher in low and middle-income countries, the researchers noted.
The team highlighted South Asian countries, where values were above 50 percent for men in the 1950s and 1960s. In India, the death rate for children under five was higher for girls than for boys and has remained higher for girls in recent years. Fewer girls than boys above the age of 15 have died since the 1980s however, 'balancing out' the disadvantage at younger ages, they explained.
And certain external factors seem to play a key role. For example, between 2015 and 2019, the probability of males outliving females was 40 percent across the entire US population, but this statistic varied, depending on marital status and educational attainment. The probability of men outliving women was 39 percent for those who were married and 37 percent for those who weren't, and was 43 percent for those with a university degree and 39 percent for those without a high school diploma.
What's more, married men with a degree have an advantage over unmarried women, educated only to a secondary level. Couples influence each other's health, the researchers said, and this is particularly true for men, who benefit more than women from being in a stable relationship.
"A blind interpretation of life expectancy differences can sometimes lead to a distorted perception of the actual inequalities [in lifespan]," they wrote.
"Not all females outlive males, even if a majority do. But the minority that do not is not small… [the findings indicate] that 40 percent of males have a longer lifespan than that of a randomly paired female."
The data nevertheless showed that overall, the death rate has fallen faster for women than for men under the age of 50, especially in the first half of the 20th century; largely as a result of improvements in infant and child mortality rates.
And men have not only maintained their survival disadvantage at younger ages, but at older ages too. They are more prone to accidents and homicides in their 20s and 30s, and they tend to smoke and drink more, leading to higher rates of cancer and death in their 60s.
A more nuanced approach to sex differences in survival is needed, said the researchers.
"Efforts in reducing lifespan inequalities must thus target diverse factors, causes and ages," they concluded.
