Has Human Life Expectancy Reached Its Limit?
Has Human Life Expectancy Reached Its Limit?
今回は「人の寿命」に関する研究がテーマです。最新の分析では、医療が進んでも平均寿命の伸びが鈍くなっており、「寿命には限界があるのでは」との声も出ています。記事では人がどれくらい生きられるかという意味で「lifespan（寿命）」という単語が使われており、「extend lifespan（寿命を延ばす）」「average lifespan（平均寿命）」などの形でよく使われます。あなたは、健康で長生きするために、どんなことを意識していますか？講師と話してみましょう。
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A new study says humanity is hitting the upper limit of life expectancy.
Developments in medical technology and genetic research are not leading to major increases in lifespan overall, the researchers said.
The study was published recently in Nature Aging.
“We have to recognize there’s a limit” and possibly change ideas about when people should retire and how much money they will need to live out their lives, said S. Jay Olshansky of the University of Illinois-Chicago. Olshansky was the lead writer of the study.
Mark Hayward of the University of Texas was not involved in the study. However, he called it “a valuable addition to the mortality literature.”
“We are reaching a plateau” in life expectancy, he said.
It is always possible that some new development could push survival to greater lengths, “but we don’t have that now,” Hayward said.
Life expectancy is one of the world’s most important health measures. Still the life expectancy measurement has problems. For example, life expectancy is an estimate that cannot include new developments or changes that might affect the length of people’s lives.
These unknown developments could include pandemics or new treatments for diseases.
In the recent study, Olshansky and other researchers followed life expectancy estimates for the years 1990 to 2019. They took information from a database administered by the Max Planck Institute for Demographic Research.
The researchers paid special attention to eight of the places in the world where people live the longest: Australia, France, Hong Kong, Italy, Japan, South Korea, Spain and Switzerland.
The United States does not rank in the top 40, but it was included in the study because the researchers live in the U.S. Also, some experts have made estimates that life expectancy in the U.S. would increase greatly in the 2000s, Olshansky said.
Life expectancy measurements in the U.S. are more difficult. The country is affected by a number of causes of early death. Examples include drug overdoses, shootings, weight problems and uneven health care services.
But in one calculation, the researchers estimated what would happen in all nine places if all deaths before age 50 were prevented. The increase at best was still only 1.5 years, Olshansky said.
The study suggests that there is a limit to how long most people live, and we have almost hit it, Olshansky said.
“We’re squeezing less and less life out of these life-extending technologies. And the reason is, aging gets in the way,” he said.
It may seem common to hear of a person living to 100. Former U.S. President Jimmy Carter, for example, recently celebrated his 100th birthday.
In 2019, a little over two percent of Americans made it to 100, compared to about five percent in Japan and nine percent in Hong Kong, Olshansky said.
It is likely that the number of people who reach 100 will grow in the years ahead, experts say, but that is because of population growth. The percentage of people hitting 100 will remain limited, likely with fewer than 15 percent of women and 5 percent of men making it that long in most countries, Olshansky said.
Developments in medical technology and genetic research are not leading to major increases in lifespan overall, the researchers said.
The study was published recently in Nature Aging.
“We have to recognize there’s a limit” and possibly change ideas about when people should retire and how much money they will need to live out their lives, said S. Jay Olshansky of the University of Illinois-Chicago. Olshansky was the lead writer of the study.
Mark Hayward of the University of Texas was not involved in the study. However, he called it “a valuable addition to the mortality literature.”
“We are reaching a plateau” in life expectancy, he said.
It is always possible that some new development could push survival to greater lengths, “but we don’t have that now,” Hayward said.
What is life expectancy?
Life expectancy is an estimate of the average number of years a baby born in a particular year might expect to live. The measurement assumes death rates at the time of birth do not change.Life expectancy is one of the world’s most important health measures. Still the life expectancy measurement has problems. For example, life expectancy is an estimate that cannot include new developments or changes that might affect the length of people’s lives.
These unknown developments could include pandemics or new treatments for diseases.
In the recent study, Olshansky and other researchers followed life expectancy estimates for the years 1990 to 2019. They took information from a database administered by the Max Planck Institute for Demographic Research.
The researchers paid special attention to eight of the places in the world where people live the longest: Australia, France, Hong Kong, Italy, Japan, South Korea, Spain and Switzerland.
The United States does not rank in the top 40, but it was included in the study because the researchers live in the U.S. Also, some experts have made estimates that life expectancy in the U.S. would increase greatly in the 2000s, Olshansky said.
Who lives the longest?
Women continue to live longer than men. Female life expectancy improvements are still happening — but at a slower rate, the researchers found. In 1990, the average amount of improvement was about 2.5 years every 10 years. In the 2010s, it was 1.5 years — but almost zero in the United States.Life expectancy measurements in the U.S. are more difficult. The country is affected by a number of causes of early death. Examples include drug overdoses, shootings, weight problems and uneven health care services.
But in one calculation, the researchers estimated what would happen in all nine places if all deaths before age 50 were prevented. The increase at best was still only 1.5 years, Olshansky said.
The study suggests that there is a limit to how long most people live, and we have almost hit it, Olshansky said.
“We’re squeezing less and less life out of these life-extending technologies. And the reason is, aging gets in the way,” he said.
It may seem common to hear of a person living to 100. Former U.S. President Jimmy Carter, for example, recently celebrated his 100th birthday.
In 2019, a little over two percent of Americans made it to 100, compared to about five percent in Japan and nine percent in Hong Kong, Olshansky said.
It is likely that the number of people who reach 100 will grow in the years ahead, experts say, but that is because of population growth. The percentage of people hitting 100 will remain limited, likely with fewer than 15 percent of women and 5 percent of men making it that long in most countries, Olshansky said.
Mike Stobbe reported on this story for the Associated Press. John Russell adapted it for VOA Learning English.
Source：Has Human Life Expectancy Reached Its Limit?
VOA
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