The world is awash in studies on longevity. Perhaps the most famous are those from Dan Buettner who identified several "Blue Zones" around the globe -- in places like Japan, Greece, Italy -- which boast unusually high numbers of centenarians. Buettner credits the longevity of these people to moderate exercise, healthy social connections, strong family ties, and mostly vegetarian diets with a moderate amount of alcohol.
But what about here in the United States? I ran across a 2020 study from Washington State University that analyzed the elderly in the state of Washington. The researchers identified a number of factors associated with longevity -- and a few that aren't. Their conclusions were derived from a somewhat narrow study of 144,000 people, age 75 and older, in just one state. But it's reasonable to think that the results apply to the rest of us as well.
Less than 2% of us reach the ripe old age of 100. However, because of advances in medicine and public health, the number of centenarians is projected to increase dramatically, from less than a million today to an estimated 3.7 million in 2050. Still, social and environmental factors -- not the latest surgical techniques -- are the main determinants of healthy aging, which is defined as "the process of developing and maintaining the functional ability that enables well-being in older age."
So here's what the Washington researchers found:
Race and gender. Women are more likely than men to live to see 100. White people are more likely to reach 100 than African Americans. However, Hispanics and Asians have lower mortality rates compared to both African Americans and white Americans at all ages, and thus have the best chance to cross the centenarian goal line.
Neighborhood. Living in a walkable neighborhood has "a strong positive correlation" with the likelihood of living to 100. Walking, a healthy activity in itself, is associated with lower body mass index and other measures of health. But also, people in walkable neighborhoods typically have access to public transit, medical facilities, healthy food and other helpful goods and services.
Marital status. Compared to married older adults, those who never married or were widowed, divorced or separated were more likely to become centenarians. This also flies in the face of some previous research which has identified a "marriage protection" for older people due to greater social connectedness, less self-destructive behavior, and the healthier habits generally found in married people. But this study found that the marriage protection seems less relevant among older people. Why? They may have became widowed earlier in life; hence stress associated with the trauma is long gone. The study also included more women, who suffer less negative effects from the break-up of a marriage than men. Additionally, some people still married may be experiencing a strained relationship which can take its own toll on health.
Socioeconomic status. People who live in middle and upper middle-class areas are more likely to reach age 100 than those who live in poor areas. A higher income is associated with all kinds of advantages, including closer and stronger social connections, as well as healthier lifestyle choices and better access to medical facilities, parks and recreational activities and many other social services.
Population. The study found clusters of healthy older people in urban, higher socioeconomic areas, but very few centenarians in rural areas of the state. The researchers concluded that these communities, with more younger working people, enjoyed more government support, greater availability of community organizations, better access to transportation and health care services -- all factors that separately influence longevity and the chance of become a centenarian.
What does all this mean for us? Many of the factors that determine our longevity, such as race and gender, are beyond our control. But lifestyle matters a lot. We can exercise more, eat healthier diets, develop stronger social connections -- not so much to improve our chances to live to 100, but more to support "the process of developing and maintaining the functional ability that enables well-being in older age."