Longevity Yin and Yang
Your Years Are Numbered…
It may not be possible to extend the human life span beyond the ages already attained by the oldest people on record, Einstein scientists reported last October in Nature.
Since the 19th century, average life expectancy has risen almost continuously thanks to improvements in public health and other areas. On average, for example, U.S. babies born today can expect to live to nearly age 79 compared with an average life expectancy of only 47 for Americans born in 1900. Since the 1970s, the maximum duration of life—the age to which the oldest people live—has also risen. But the Einstein researchers found that this upward arc for maximal life span has a ceiling—and we’ve already touched it.
“Demographers as well as biologists have contended there is no reason to think that the ongoing increase in maximum life span will end soon,” says senior author Jan Vijg, Ph.D., a professor and chair of genetics, the Lola and Saul Kramer Chair in Molecular Genetics and a professor of ophthalmology and visual sciences at Einstein. “But our data strongly suggest that it has already been attained.”
When Dr. Vijg and colleagues looked at survival improvements since 1900 for people age 100 and above, they found that gains in survival peaked at around 100 and then declined rapidly, regardless of the year people were born. “This finding indicates diminishing gains in reducing late-life mortality and a possible limit to human life span,” says Dr. Vijg.
Using maximum-reported-age-at-death data, the Einstein researchers put the average maximum human life span at 115 years—a calculation allowing for record-oldest individuals occasionally living fewer or more than 115 years. (Jeanne Calment—the French woman who died in 1997 at age 122, after living longer than any person in recorded history—was a statistical outlier, they concluded.) The researchers calculated that the probability in a given year of seeing one person live to 125 anywhere in the world is less than one in 10,000.
…But Last Ones Can Be Golden
The final years of an exceptionally long life could well be healthy ones, Einstein researchers reported last summer in the Journal of the American Geriatrics Society.
“Most people struggle with an ever-increasing burden of disease and disability as they age,” says study leader Nir Barzilai, M.D., a professor of medicine and of genetics at Einstein and director of Einstein’s Institute for Aging Research. “But we found that those who live exceptionally long lives have the additional benefit of shorter periods of illness—sometimes just weeks or months—before death.”
Dr. Barzilai and colleagues looked at the health status of centenarians and near-centenarians enrolled in two ongoing studies: the Longevity Genes Project and the New England Centenarian Study. Both studies also included noncentenarian comparison groups.
The long-lived participants in these two studies proved markedly similar with respect to major illness: Compared to the younger groups, their onset of major age-related disease was delayed, with serious illness compressed into a few years very late in life. The findings contradict the notion that the older people get, the sicker they become and the greater the cost of taking care of them.
Dr. Barzilai is also the Ingeborg and Ira Leon Rennert Chair in Aging Research and an attending physician in endocrinology at Montefiore.