More people are living to be 100: Here’s why

Story at a glance


  • America’s population is aging, with more people living to be 100.


  • Reaching extreme old age depends on multiple factors like location, gender, lifestyle and parental age of death.


  • Medical advances, lifestyle changes and rapid growth in population have all contributed to the influx of centenarians.


The average lifespan in the United States has taken a hit in recent years in part due to the COVID-19 pandemic and the opioid crisis. But the nation’s population is growing older with more people living to 100 than in decades past.

There were 89,739 centenarians living in the United States in 2021, nearly twice as many as there were 20 years ago, according to data from the Population Division of the United Nations.

And one of the oldest living people on the planet is a California-born Catalan woman named María Branyas Morera who turned 115 years old on Jan. 19, according to the Guinness world records website.


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People are living longer for complex reasons but here are a few factors contributing to the growing number of centenarians.

Improved public health and medical advances

Between 1900 and 2020 the average life expectancy in the United State rose by more than 30 years due, in part, to multiple public health measures.

Infectious diseases deaths began to decline after the U.S started chlorinating drinking water in 1908 to kill off water-born illnesses like typhoid, cholera and dysentery.

The discovery and introduction of antibiotics like penicillin in the early 20th century helped lower mortality rates among people with bacterial infections. Experts estimate that in about 100 years antibiotics extended the average lifespan in the U.S by 23 years.

The popularization of home refrigeration, pasteurization and new food safety regulations to control bacteria also contributed to lower rates of infection.

Medical advances have also played a profound role in expanding the average American’s lifespan over the past century. One example of this is the medical leaps that have been made in diagnosing and treating heart disease.

“Forty years ago, if you had a heart attack there was a very good chance that you might not survive from it,” said Mark Lachs, co-chief of the Division of Geriatrics and Palliative Medicine at Weill Cornell Medicine and New York Presbyterian.

“Now, we put a piece of rigatoni in one of your arteries, a stent, and you get to live another twenty, thirty, or forty years.”

Better lifestyle choices

Heart disease has been the leading cause of death in the U.S. since at least the 1950s, according to the Centers for Disease Control and Prevention, with heart-related conditions accounting for 588.8 deaths per 100,000 people that year alone.

That ratio fell by more than half by the year 2000, and by 2019 heart disease accounted for 161.5 deaths per 100,000 people in the U.S., according to agency data.

The nation’s drastic decline in heart disease deaths is in part due to the more Americans giving up smoking, which research shows can knock off at least 10 years from a person’s life expectancy.

In 1965, 45 percent of Americans over the age of 18 smoked. Since then, the number of adult smokers has dwindled with only 12.5 percent of adults admitting to smoking in 2020.

Population growth  

In 1915, 10 percent of all babies born in the U.S. died before they reached their first birthday, according to CDC data. But better medicine, better hygiene and a bevy of public health measures eventually drastically reduced maternal and infant mortality rates.

But the most important force behind the increased number of centenarians is the “Baby Boom” generation, according to S. Jay Olshanksy, a professor of epidemiology and biostatistics at the University of Illinois, Chicago who also spoke with The Washington Post.

“If you have 100,000 people you aren’t going to have that many people that are going to make it out to 100 years old,” said Olshanksy. “But if you have 7 billion people on the planet the probability of more people making it past 100 increases dramatically.”

The United States experienced a 20-year increase in birth rates following the end of World War II until 1964, commonly referred to as the Baby Boom. During that time, at least 72 million babies were born making the “baby boomer” generation the second largest in U.S. history.

“After the baby boom population dies off, we may actually see a decline in the number of centenarians,” said Thomas Perls, a professor at Boston University Chobanian & Avedisian School of Medicine with a specialty in aging.

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