Men and women have different life expectancies. The gap's growing in the US and shrinking in Europe. But it exists in non-human animals, too. Why is that?Take a look around your average retirement home or advanced-age friend group and you'll see a significant sex imbalance. Men are rare among the 85-and-overs. Common wisdom is that they die earlier than women, and the numbers support it.

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In Germany in 2022, for example, men had an average life expectancy of just over 78 years, while women's life expectancy was at 82.8 years.

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In the US, the average life expectancy for women was around 79 in 2021, while for men it was a little over 73 years. This gap of 5.8 years is the largest it's been since 1996.

In a new study, US researchers explain that external factors, chief among them the COVID-19 pandemic, are to blame for the widening gap.

In the paper, published in the JAMA Journal of Internal Medicine in November 2023, the authors say that the pandemic disproportionately affected men in the US and contributed to bringing down their average life expectancy.

The other major contributor to men's lower life expectancy are what the researchers call "deaths of despair" — lives cut short by suicide, addiction issues or violent crime, for example.

"While rates of death from drug overdose and homicide have climbed for both men and women, it is clear that men constitute an increasingly disproportionate share of these deaths," said the study's lead author, Brandon Yan.

Dangerous jobs, heart disease also reasons for men's earlier deaths

There are other causes for the gap in life expectancy between men and women.

Robert H. Shmerling, a rheumatologist and senior faculty editor at Harvard Health Publishing, lists the facts that men on average are more likely to skip routine health check-ups, and that men far outnumber women in dangerous jobs, such as firefighting or military combat.

Shmerling, too, points to the fact that men commit suicide more often than women. One potential reason for this could be the stigma that is still attached to mental health care in many cultures, especially for men.

Another big factor, the medical expert says: Heart disease. Men in the US are 50% more likely to die of heart disease than women.

In Europe, men fare better

Outside of the US, the decline of cardiovascular disease in men is a reason that the life expectancy gap between the sexes is shrinking.

A team of authors from Germany's Federal Institute for Population Research examined life expectancy by sex in Austria, the Czech Republic, Denmark, France, Germany, Slovakia and Switzerland, and found that the mortality difference between the sexes had decreased.

The results, published in the European Journal of Public Health in July 2023, show that declines in the life expectancy gap between the sexes "were mostly driven by a reduction of male excess mortality from cardiovascular diseases and neoplasms."

Neoplasms are tumors — and malignant ones are cancers.

Between 1996 and 2019, the mortality gap decreased in all seven countries included in the study.

In most countries, this was primarily due to a reduction of heart disease among men. In France, a reduction in cancers among men contributed significantly to a shrinking mortality sex gap.

It's not all good news, though. In the Czech Republic, the difference between how long men and women live has decreased because fewer men are dying from lung cancer — while women's death rates from lung cancer are increasing.

Courtship and mating behavior responsible for shorter life of male mammals

Humans are not the only animals with a marked difference in life spans between the sexes.

In March 2020, a study by an international team of researchers showed that in the wild, female mammals lived longer than males. The study was published in the Proceedings of the National Academy of Sciences.

In the 101 species the scientists studied, females' median lifespan was on average 18.6% longer than that of males. In humans, by contrast, that number stands at 7.8%.

One species where this was obvious: bighorn sheep. The case of the wooly mammals also showed the researchers, however, that differences in life expectancy only occur in rough times. When living conditions are favorable for the sheep and there's enough food for everyone, males don't die significantly earlier than females.

But when things look less rosy, female bighorn sheep are better at coping, partly because they have more energy to expend on feeding.

Males on the other hand are thought to spend a lot of energy on sexual competition or building muscles. Aggression, then, seems to decrease life expectancy — that goes for males across species, including humans.

Edited by: Zulfikar Abbany

(The above story first appeared on LatestLY on Nov 17, 2023 08:10 PM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).