Why do women live longer than men?

Why do women live longer than men?
Steven Austad. Credit: UAB

Women live longer than men. This simple statement holds a tantalizing riddle that Steven Austad, Ph.D., and Kathleen Fischer, Ph.D., of the University of Alabama at Birmingham explore in a perspective piece published in Cell Metabolism on June 14.

"Humans are the only species in which one sex is known to have a ubiquitous survival advantage," the UAB researchers write in their research review covering a multitude of species. "Indeed, the sex difference in longevity may be one of the most robust features of human biology."

Though other species, from roundworms and fruit flies to a spectrum of mammals, show lifespan differences that may favor one sex in certain studies, contradictory studies with different diets, mating patterns or environmental conditions often flip that advantage to the other sex. With humans, however, it appears to be all females all the time.

"We don't know why live longer," said Austad, distinguished professor and chair of the UAB Department of Biology in the UAB College of Arts and Sciences. "It's amazing that it hasn't become a stronger focus of research in human biology."

Evidence of the longer lifespans for women includes:

  • The Human Mortality Database, which has complete lifespan tables for men and women from 38 countries that go back as far as 1751 for Sweden and 1816 for France. "Given this high data quality, it is impressive that for all 38 countries for every year in the database, female life expectancy at birth exceeds male life expectancy," write Austad and Fischer, a research assistant professor of biology.
  • A lifelong advantage. Longer female survival expectancy is seen across the lifespan, at early life (birth to 5 years old) and at age 50. It is also seen at the end of life, where Gerontology Research Group data for the oldest of the old show that women make up 90 percent of the supercentenarians, those who live to 110 years of age or longer.
  • The birth cohorts from the mid-1800s to the early 1900s for Iceland. This small, genetically homogenous country—which was beset by catastrophes such as famine, flooding, volcanic eruptions and disease epidemics—provides a particularly vivid example of female survival, Austad and Fischer say. Over that time, " at birth fell to as low as 21 years during catastrophes and rose to as high as 69 years during good times," they write. "Yet in every year, regardless of food availability or pestilence, women at the beginning of life and near its end survived better than men."
  • Resistance to most of the major causes of death. "Of the 15 top causes of death in the United States in 2013, women died at a lower age-adjusted rate of 13 of them, including all of the top six causes," they write. "For one cause, stroke, there was no sex bias, and for one other, Alzheimer's disease, women were more at risk."

Cell Metabolism invited Austad to contribute this perspective paper, "Sex differences in lifespan."

Austad first became interested in the topic when Georgetown University asked him to lecture on it in 2003. Although lab models like the roundworm C. elegans, the fruit fly Drosophila melanogaster and the mouse Mus musculus are intensively used in scientific studies, people in those fields are not very aware of how longevity patterns by sex can vary according to genetic backgrounds, or by differences in diet, housing or mating conditions, Austad says.

Those uncontrolled variables lead to different results in longevity research. A survey of 118 studies of laboratory mice by Austad and colleagues in 2011 found that 65 studies reported that males outlived females, 51 found that females outlived males, and two showed no sex difference.

But if variables are carefully controlled, mice may prove to be a useful model to study sex differences in the cellular and molecular physiology of aging, Austad and Fischer write.

This understanding will be helpful as researchers start to develop drugs for human use that affect aging, Austad says. "We may be able to develop better approaches," he said. "There is some complicated biology underlying sex differences that we need to work on."

Differences may be due to hormones, perhaps as early as the surge in testosterone during male sexual differentiation in the uterus. Longevity may also relate to immune system differences, responses to oxidative stress, mitochondrial fitness or even the fact that men have one X chromosome (and one Y), while women have two X chromosomes.

But the female advantage has a thorn.

"One of the most puzzling aspects of human sex difference biology," write Austad and Fischer, "something that has no known equivalent in other species, is that for all their robustness relative to men in terms of survival, women on average appear to be in poorer health than men through adult life."

This higher prevalence of physical limitations in later life is seen not only in Western societies, they say, but also for women in Bangladesh, China, Egypt, Guatemala, India, Indonesia, Jamaica, Malaysia, Mexico, the Philippines, Thailand and Tunisia.

One intriguing explanation for this mortality-morbidity paradox is a possible connection with health problems that appear in later life. Women are more prone to joint and bone problems, such as osteoarthritis, osteoporosis and back pain, than are men. Back and joint pain tends to be more severe in women, and this could mean chronic sleep deprivation and stress. Thus, the in morbidity could be due to connective tissue maladies in women, and connective tissue in humans is known to respond to female hormones.

But this is just one of several plausible hypotheses for the mystery of why women live longer, on average, than men.


Explore further

Lowered birth rates one reason why women outlive men

More information: Cell Metabolism, DOI: 10.1016/j.cmet.2016.05.019
Journal information: Cell Metabolism

Citation: Why do women live longer than men? (2016, June 14) retrieved 23 July 2019 from https://phys.org/news/2016-06-women-longer-men.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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Jun 14, 2016
NURSES are FEMALES, That's Why!
More Peemales in Waste. That's why.

Jun 14, 2016
lower pressure, i.e. heart muscle

Jun 15, 2016
I thought the reason why woman live longer was already well known and pretty obvious?
Men tend to smoke more, drink more, take more unnecessary health risks, more often die of accidents such as from riding cars/motorcycles too fast; generally greater risk taking ?

Jun 15, 2016
Why do men die before their wives? ...because they want to!

(Old joke)

Jun 15, 2016
One word STRESS. Men handle it worse than women.

Jun 15, 2016
2 Reasons Women live longer or Men die sooner.
#1 Testosterone in men is hard on the system (like burning a candle at both ends). Study people born as men that switch to being women and the reverse, study women who transition to men and use testosterone. Of course there are factors like men are more likely to engage in hostile actions like war or driving too fast or smoking to look cool that could all be linked back to testosterone, but even if you factor out anger based thinking, and look at Testosterone only from the chemical side it will be seen as gas to the life fire.
#2 Women that have children live longer. I think there are reports that show for each child up to about 6, this will extend max lifespan. Not sure if it has to do with stem cells or what we know from young blood studies, but has something to do with being in contact with creating new life will extend the life of the mother as well as part of a survival gift nature. Why pregnant women have radiant hair or glow?

Jun 15, 2016
One word, women! It's the only way to truly get away from them.

Jun 15, 2016
Short people live longer. Women are shorter than men, therefore they live longer.
http://www.ncbi.n.../1600586

Jun 15, 2016
One word STRESS. Men handle it worse than women.

Actually... men probably handle stress better. It's just that women are always busy seeking more ways of piling more of it on...
It's their "job".


Jun 15, 2016
You forgot one main word: _e_o_e_e_. Can anybody guess it?

Jun 15, 2016
You forgot one main word: _e_o_e_e_. Can anybody guess it?

Oh, man... Can I buy a consonant?

Jun 15, 2016
Men are nothing but sperm donors. Women are the species. That's just a fact.

Jun 15, 2016
You forgot one main word: _e_o_e_e_. Can anybody guess it?

telomeres.
What do I win?

Jun 15, 2016
Men are nothing but sperm donors. Women are the species. That's just a fact.

Man, you've been married a while, haven't ya...:-)?

Jun 15, 2016
You forgot one main word: _e_o_e_e_. Can anybody guess it?

telomeres.
What do I win?

A baby's arm, sticking out of a bowling ball?
(Thanks to - "Whaddaya Want from Life", by the Fee Waybill and The Tubes...)

Jun 15, 2016
Men are nothing but sperm donors. Women are the species. That's just a fact.

Man, you've been married a while, haven't ya...:-)?


Maaayyyybeee

Maybe just a tongue-in-cheek response to the knee-jerk misogynism a thread like this attracts... ;-)

Jun 16, 2016
A baby's arm, sticking out of a bowling ball?
(Thanks to - "Whaddaya Want from Life", by the Fee Waybill and The Tubes...)

LOL.
That's a gem. Thanks.

Jun 17, 2016
Men are nothing but sperm donors. Women are the species. That's just a fact.


Nothing wrong with being a sperm donor. I donate mine several times a week.
:-) Ain'r life grand.

Jun 17, 2016
>"Humans are the only species in which one sex is known to have a ubiquitous survival advantage," the UAB researchers write in their research review covering a multitude of species.

I don't have access to the full text, but this claim is grossly misleading at best. What about orcas, elephants, antechinuses, tarantulas, and sexually cannibalistic arthropods generally? Sure, these species are mostly not intensively studied in the lab, but there's no reason to think the female survival advantage consistently observed in the wild is NOT ubiquitous. And for antechinuses at least, unless my knowledge is outdated, the sex difference is extremely robust in lab studies as well.

Jun 18, 2016
It ain't easy being king. Take a look at a pride of lions, and it becomes obvious that there are more females than males, usually at a ratio of about 2- or 3-to-1. Considering that male and female lions are born in equal numbers, the question arises: What happens to the missing males?

Jun 18, 2016
Only about 1 in 8 male lions survive to adulthood

Jun 18, 2016
Men engage in activities that weed out a class of male that might well be able to survive to extended old age. The best male physical specimens are engaged in warfare of some sort all their lives. There are very few female warriors. Men take on the dangerous professions like mining, farming, steel mills, etc., women generally do not. Even contact sports (safe warfare[?]) among men shortens their lives, like boxing, football, etc., due to head trauma, etc. If these activities are not accounted for by only looking at "birth to 5 years" and "over 50" survival rates, the weeding out (during the period between these cohort samples) >>of the most fit males<< creates a bias of massive proportions.

An interesting test of this theory is to use the the data bases in the article and compare the differences against the times of warfare in these data cohorts. We need more detailed knowledge of the numbers of males killed in dangerous wars, professions, etc., and subsequent survival rates.

Jun 19, 2016
Study a year ago determined woman sleep on average 30 mins more per day. Interestingly , that meant men live more waking hours on average. Sleep is safer, lower metabolism, and stress relief. That article, posted here on physorg, concluded this as a compelling factor in longevity bias.

Jun 19, 2016
Give women Testosterone. I bet they don't live as long as a control group

Jul 12, 2016
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Jul 12, 2016
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