Human Longevity: Can It Be Further Extended?

 Hello. This is Dr JoAnn Manson, professor of medicine at Harvard Medical School and Brigham and Women's Hospital. I'd like to talk with you about a recent interesting article in the journal Nature Aging that addresses the question of whether the major strides in life expectancy seen in the 20th century can be expected to continue into the current century.

As we all know, there were dramatic improvements in life expectancy in the 1900s. At the turn of that century, the average median life expectancy at birth was only about 50 years. Over the course of the century, on average, there was a 30-year increase in life expectancy. There was a gain of about 3 years in lifespan for every 10 years of the decade, and this was due to a combination of several factors: improvements in public health and medicine, dramatic declines in deaths in infancy and in childhood deaths from life-threatening infections, and improvements in prevention and treatment of chronic diseases. 

These authors wanted to look at the past 30 years in developed countries and see whether similar trends toward improved life expectancy are present. They used national vital statistics and survivorship data from eight highly developed countries.

With the longest-living populations in Europe, Asia, and Australia, they added the United States and Hong Kong, and looked at the data from 1990 through 2019. They excluded 2020 to avoid any influence from the COVID pandemic. They found that we're nowhere near such great gains in life expectancy over those 30 years.

In fact, they found overall a deceleration of the gain in life expectancy over that period. It was relatively stable with only very modest gains over that 30-year period. 

Currently, about 2% of males and 5% of females in developed countries live past age 100, and the authors projected that only about 5% of males and 15% of females are likely to live past age 100 by the end of this century, unless there's increased attention to the underlying biology of aging and interventions that are directly related to the human biology of aging. 

We know that multiple mechanisms are involved in aging. These include DNA methylation, epigenetic aging, inflammation, the accumulation of senescent cells, and changes in mitochondrial function. Certain interventions have looked very promising, such as GLP-1s, metformin, rapamycin, polyphenols, and others. 

However, the authors project that with the current approach — without attention to the underlying biology of aging and interventions that are directly addressing those pathways — even in 15 years, the average lifespan in developed countries for men may be only about 86 years, and for women, perhaps a little more than 90 years. This is still nowhere near what had been previously projected, which was half of the population with current birth cohorts reaching the age of 100. 

So, in some ways, this is a call to action to prioritize rigorous research on the underlying biology of aging, the aging process, and rigorously testing interventions that may be of benefit in addition to continuing the research on prevention and treatment of chronic diseases and other medical issues that are so important.

https://www.medscape.com/viewarticle/human-longevity-can-it-be-further-extended-2024a1000kk8