Life Expectancy Drives U.S. and World Population Growth

• Edwin S. Rubenstein
• March 29, 2022
• Forum Papers
• Forum Paper
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Life Expectancy Drives U.S. and World Population Growth
An NPG Forum Paper
by Edwin S. Rubenstein
March 2022

In the latest New York Times Health Issue, author Steven Johnson notes that “Between 1920 and 2020, the average human life span doubled,” adding that “…the spike in global population has not been caused by some worldwide surge in fertility. What changed is people stopped dying.”

Ironically, Johnson’s historical narrative starts at a moment in time when it seemed people would never “stop dying.” In September 1918, a flu virus began spreading through Camp Devon, a crowded military base outside Boston. By the end of the second week, one in five soldiers came down with the illness. But the real shock, as described in the camp physician’s notes, was its lethality: “It is only a matter of a few hours then until death comes,” he wrote. “It is horrible. One can stand it to see one, two or 20 men die, but to see these poor devils dropping like flies sort of gets on your nerves. We have been averaging about 100 deaths per day.”

Sound familiar?

In fact, the 1918 flu pandemic was worse than COVID-19. The best estimates suggest as many as 100 million people died from the Spanish Flu that eventually circled the world. To put that in context, as of January 14, 2022, 5.5 million people have died from all COVID variants, on a planet with four times as many people.

A graphic may be the best way to appreciate the over-sized impact of the 1918 flu on U.S. life expectancy:

The 1918 pandemic saw a terrifying slash in U.S. life expectancy. Practically overnight expectancy plunged by 12 years, from 51 in 1917 to 39 in 1918. At its peak, from 1918 to 1919, nearly half of all U.S. deaths were attributed to the Spanish flu. Yet no one, except for a few Federal statisticians, knew the full extent of the calamity. There was no panic. Parents sent their children to school as before.

And – most amazingly – by 1919, life expectancy was at pre-pandemic highs. Think about it: No mask mandates, no flu vaccines, no public service announcements, and a government that never publicly acknowledged the problem. But the country was far less densely populated, our air was clearer, and extreme weather events were less frequent.

By comparison, COVID’s impact on life expectancy is barely perceptible. Look at the two points at the far right of the graphic. They are from a Federal report released last summer, and show life expectancy fell from 78.8 years in 2019 to 77.3 years in 2020, a decline of 1.5 years. But it has changed our lives completely – perhaps forever.

Two flu pandemics; two radically different reductions in life expectancy. Why?

Hint: It’s not just because of advances in medical knowledge between 1918 and 2020. The answer lies in the viruses themselves. They were different. The 1918 flu variant was unusually lethal among young adults, while deaths among older people were rare. By contrast, an older demographic – the nursing home population, for example – was more likely to succumb to the 2020 COVID variant.

Life expectancy in a given year is calculated as the average age of individuals who die in that year. When abnormal numbers of young people perish, life expectancy falls dramatically. Statistically, a 20-yearold victim of the 1918 pandemic could have lived another 31 years, had they spent their entire lives under the conditions of 1917.

When otherwise healthy older people die from COVID, average life expectancy also declines – though not nearly as much. An 85-year-old COVID victim in 2020, for example, would have lived an additional six years, on average, under the conditions of 2019.

THE DELTA DIFFERENCE

A study published in the BMJ (formerly the British Medical Journal) assessed premature deaths in 37 countries, comparing life expectancy in 2020 with what would have been if the historical trends from 2005-2019 remained in place.5 Life expectancy dropped in 31 of those countries during the pandemic.

The U.S. decline was among the worst. (U.S. men saw life expectancy decline by nearly 2.3 years.) Only Russia fared worse.

One surprise: the most recent drop in U.S. life expectancy was driven mainly by deaths of young people. In the U.S. “…we have lost a huge amount of people at a young age. That’s really, really sobering,” Dr. Nazrul Islam, an Oxford University researcher and the study’s lead author, is quoted as saying.

“Early in 2020, COVID primarily killed older U.S. adults in densely populated hot spots. But since the delta variant took hold [in the summer of 2021] the disease has shifted its burden to those who have not gotten the shot… Data says younger, Southern, rural, and white populations are now more at risk.”

The BMJ paper suggests that the U.S. did a relatively poor job of protecting young people during the pandemic and that the country’s life expectancy has dropped at a faster pace since at least World War II.

Since December 2021 the Omicron variant has infected more people than Delta and early COVID combined, but its death rate appears to be considerably lower. Young people are still dying, however, and as a result, U.S. life expectancy could well be lower in 2021
than it was in 2020…Continue reading the full Forum paper by clicking here.