With the increase in longevity, another demographic shift has taken place, said Lisa F. Berkman, director of the Harvard Center for Population and Development Studies. While people are living longer, fertility rates are going down, and both trends are reshaping the demographic pyramid, which looks less and less like a pyramid.
“What we have is a rectangularization of the pyramid,” said Berkman, who is also the Thomas D. Cabot Professor of Public Policy, Epidemiology, and Global Health and Population at Harvard T.H. Chan School of Public Health. “It’s no longer a pyramid with lots of young people at the bottom because fertility rates have declined and stayed there, or very few people at the top because longevity has increased.”
For Berkman, the demographic transformation poses a challenge to societies, which must reimagine themselves to adapt to an aging population. Keeping older people in the workforce would not displace younger workers, she said, and many companies would benefit from the “soft skills,” such as interpersonal and negotiating skills, older workers tend to have.
“Many societies were built on the wisdom of elders,” said Berkman. “In some ways, it isn’t surprising that people like Nancy Pelosi, Joe Biden, and Tony Fauci are around. What’s surprising is that they never would have been alive 50 years ago because 50 years ago, the odds of survival to 80 were so much smaller.”
The road to healthy aging
Researchers define “healthy aging” according to four areas: longevity, physical health, emotional health, and cognitive health. A person who lives into older years with good status in all four domains can be said to have “healthy aging,” said Okereke.
But social disparities play a role in healthy aging. Those who live longer and healthier lives tend to have higher income and education levels and other socio-economic advantages. Much of the disparity, said Okereke, has to do with the factors that drive early mortality. At birth, the life expectancy of a Black man in the U.S. is estimated to be at least a decade shorter than that of a non-Latinx white woman, she said.
Genetics can contribute to longevity, said Okereke, but more important in survival and healthy aging are “the choices we make as adults”: regular exercise, healthy diet, and not smoking. Social determinants of health can also tip the scales, she said.
“For example, early life factors, such as household wealth versus poverty, food and financial security versus instability, health-promoting versus traumatic environments, educational attainment and quality, and so on — these factors affect how a person can be set up to lead a longer, more healthful life versus not,” said Okereke.