Once you’ve reached the age of 75, you’re more likely to go on to celebrate your 100th birthday if you live in a walkable, mixed-age, higher-income neighborhood, suggests the findings from a study published recently in the International Journal of Environmental Research and Public Health.
And it doesn’t matter if that neighborhood is in a city or a small town, the research also found.
“Our study adds to the growing body of evidence that social and environmental factors contribute significantly to longevity,” says Rajan Bhardwaj, the study’s lead author and a medical student at Washington State University, in a released statement.
According to demographers at the U.S. Census Bureau, the United States currently has about 93,000 centenarians, up from 53,000 in 2010. During the next decade, that number is expected to reach 130,000, but it will really grow after baby boomers begin to turn 100, starting in 2046. It’s estimated that by 2060, the U.S. will have about 603,000 centenarians.
As Bhardwaj and his co-authors point out in their paper, previous research has suggested that genetics determines only 20 to 30 percent of an individual’s chance of reaching 100. That means that social and environmental factors — ones that support healthy aging — are all-important for living to a ripe old age.
But what exactly are those factors? Bhardwaj and his colleagues devised a study to try to answer that question.
For the study, the researchers examined demographic data on 144,665 residents of the state of Washington who died at age 75 or older between 2011 and 2015. The data included information regarding each person’s age, gender, race, educational level, marital status and place of residence at their time of death.
Within that group of elderly residents were 2,698 people — or 1.8 percent — who lived to be at least 100. (The oldest of them died at 114.)
Using data from the American Community Survey, the Environmental Protection Agency and other sources, the researchers gave each neighborhood represented in the study a score. The variables that went into the neighborhood scores included such things as poverty level, access to public transit, access to primary health care, walkability, percentage of working-age residents, air pollution and green space.
Next, to determine which communities had a higher probability of its residents reaching 100, the researchers subtracted 100 from the age of each person in the study at their time of death. The resulting positive and negative values were then applied to individual neighborhoods. Areas with lower overall values were considered to have a higher likelihood of having residents who reached a centenarian age, and vice versa.
The study found that neighborhood walkability was strongly associated with the likelihood of people reaching centenarian age.
“People living in walkable neighborhoods usually have easy access to public transit, healthy food clinics/hospitals, and other services,” Bhardwaj and his co-authors write. “More walkable areas allow people to walk and bike for transportation and recreational purposes, which, in turn, promotes accumulating savings and physical activity.”
“Walkable neighborhoods are especially important for older adults who may have decreased mobility and no longer drive, as they are likely to benefit from easier access to their community afforded by walkable neighborhoods,” they add.
The study also found a strong correlation between age diversity in a neighborhood and the likelihood that its elderly residents will reach 100.
“Communities with higher working age populations [people aged 15 to 64] have higher socioeconomic status, more government support, and better access to transportation and healthcare services,” the researchers explain. “These factors have been shown separately to influence longevity and the chance of becoming a centenarian.”
While neighborhoods with higher incomes were more likely to produce centenarians, those with higher education levels were not. This finding may reflect that fact that college degrees have become more common and therefore their value in terms of living longer may not be as strong as it was for previous generations, the study’s authors explain.
Another unexpected finding was that being never married, divorced or widowed raised the likelihood of living to 100. Previous research has suggested that the converse was true, that marriage confers a health benefit in old age, particularly for men. It could be, however, that not having the stress of an unhappy marriage — or not having to care for a spouse in old age — confers some kind of longevity benefit, the findings from the current study suggest.
The study also found that women were much more likely than men to become centenarians, and that, consistent with previous research, racial minorities in the United States were much less likely. The latter finding is related to the large racial and ethnic disparities that pervade the U.S. in such domains as health, housing, employment and income, the researchers point out.
Limitations and implications
This study is observational, so it can’t prove a cause-and-effect relationship between specific neighborhood characteristics and longevity. In addition, it involved only people living in Washington state, so the findings may not be applicable to people living elsewhere.
Another limitation is that only the home address at the time of the people’s death. It’s not known what influence, if any, the people’s previous neighborhoods had on their longevity.
Still, plenty of other research has linked living in a walkable neighborhood — particularly those with ample green space — with better physical and psychological health. The current study suggests that such neighborhoods may promote longevity as well.
FMI: You can read the study in on the International Journal of Environmental Research and Public Health website.