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SALT LAKE CITY — It’s well known that women have generally outlived men for at least a century. But the size of the gap in life expectancy at birth is the biggest it’s been since 1996. Research by the University of California San Francisco and Harvard T.H. Chan School of Public Health finds that in the U.S., women outlive men by nearly six years.
The research paper was published this week in JAMA Internal Medicine.
According to the study, the difference between how long men and women are expected to live rose to 5.8 years in 2021 — an increase from 4.8 years in 2010, the year when the gap was the smallest in recent memory.
According to the UCSF-Harvard analysis, the life expectancy was 76.1 years overall in 2021, down from 78.8 years in 2019 and 77 years in 2020.
The researchers said that the pandemic hit men especially hard and accounted the most for the widening of the gap from 2019 to 2021. Other major contributors were unintentional injuries and poisonings — including overdose deaths — accidents and suicides.
“There’s been a lot of research into the decline in life expectancy in recent years, but no one has systematically analyzed why the gap between men and women has been widening since 2010,” study first author Dr. Brandon Yan, a UCSF internal medicine resident physician and research fellow at Harvard, said in a news release.
“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,” he said.
The researchers said that before COVID-19’s deadly toll, unintentional injuries, diabetes, suicide, homicide and heart disease accounted for the gaps in life expectancy. But the pandemic hit men harder than women, “likely due to a number of reasons, including differences in health behaviors, as well as social factors such as the risk of exposure at work, reluctance to seek medical care, incarceration and housing instability,” the release said. “Chronic metabolic disorders, mental illness and gun violence also contributed.”
“Deaths of despair” are also driving the trend. As Boston Herald explains, that refers to “the increase in deaths from such causes as suicide, drug use disorders and alcoholic liver disease, which are often connected with economic hardship, depression and stress.”
Calculating life expectancy
The researchers used data from the National Center for Health Statistics to identify what was killing people and thus lowering life expectancy. Then they calculated the impact on men and women to estimate the gap between the two.
Yan said more work is needed to see if directing specialized care at men could help narrow the gap and let men live longer than they are now. And with COVID-19 less dramatically deadly than in its early stages before vaccines, COVID’s contribution might change in the future.
“We need to track these trends closely as the pandemic recedes,” said senior author Dr. Howard Koh, a professor of public health leadership at Harvard. “And we must make significant investments in prevention and care to ensure that this widening disparity, among many others, does not become entrenched.”
There are some slight variations in life expectancy calculations. According to the Centers for Disease Control and Prevention, the life expectancy for both sexes in 2021 is 76.4 years. Broken down by sex, males have a life expectancy of 73.5 years, while females live 79.3 years on average in 2021. The gap is the same 5.8 years calculated by UCSF-Harvard.
The female advantage
Life expectancy is a complicated estimate of the number of years a person can expect to live. And dramatic changes to what’s going on can change the estimates.
According to IFL Science, “Females, on average, live longer than males. This is true of our own species, as well as others in the animal kingdom. Previous research attempting to explain the gap in life expectancy has suggested that it might have something to do with sex chromosomes. Biological females have two X chromosomes, while males have an X and a Y, putting them at greater risk of X-linked abnormalities. Loss of the Y chromosome as we age could also account for the trend.”
The article notes other explanations include the risk of having heart disease — female hormones may help reduce that for females — size differences between males and females and “differences in occupations, risk-taking and willingness to see a doctor.”
A 2020 Harvard Health Publishing blog by Dr. Robert H. Shmerling, senior faculty editor, unpacked those a bit, noting that men not only die more often of heart disease than women do, but they also do so at a younger age. And while acknowledging all the factors above that may account for the difference, he added that men tend to be less socially connected than women, which also contributes to greater risk of death.