If aging occurred as a random event, unaffected by external variables, the distribution of older adults would be equal across geography regardless of what individuals do or how they live. But we do not see that.
Instead, what we find are distinct clusters of older adults. Wealthy countries have proportionally more older adults than poor countries, Blacks and minority groups have lower percentages of adults living to older ages. Educational levels and income increase longevity, long-lived parents have long-lived children, happy healthy people live longer, obese people die earlier. Taller people die earlier, women who give birth later in life live longer and have longer-lived children, long-lived people escape diseases, and women outlive men.
Michelle Poulain a demographer who identified the "Blue Zones" while marking communities of centenarians on a map with his blue pen, has come up with a number of clusters. And they are all related to geography. The only clusters of extreme long-lived older adults are found in natural environments in traditional cultures within a confined geography. These "Blue Zones" are places of exceptional longevity.
Recent advances in genetic manipulation in animals which increases life expectancy by 30 to 50 percent is overshadowing studies of geography that show similar improvements in life expectancy of similar magnitude.
Where we live is just as important in promoting longevity as biological manipulations. For example some Black inmates in prison live longer than their peers living in the community. Our environment can protect us from harm, but can it also promote health? Numerous studies have shown that both monks and nuns living in religious orders live much longer by a margin of 11 to 31 percent. And we all live in segregated communities.
Rich people live in rich neighborhoods and poor people live in poor neighborhoods. And it seems that being in a place where we belong promotes health. Researchers found that low-income older adults living in high-income neighborhoods had poorer physical functioning, more functional limitations, worse self-rated health, worse cognitive ability, and were lonelier than low-income adults who lived in low-income neighborhoods. Being in a high-income neighborhood did not confer an advantage because they did not belong.
The process whereby the feeling of belonging is translated into a longer life is turning out to be simple. Researchers are exposing the role of how genes have a capacity to switch on and off according to the internal environment in our bodies. Epi-genes, as they are known, can be switched on and off, allowing for the expression or suppression of our genetic information.
The environment can trigger epigenetic changes. In addition, how we feel about our community changes our internal chemicals which affect our epigenetic makeup. How we feel about where we live changes how our body expresses our genes.
Which might explain why it is that the only clusters of extreme long-lived older adults are found in natural environments in traditional cultures within a community that they belong to. The feeling of belonging translates into our bodies being contented and not ready to shut down. If we understood the body better we would not need to know the brain.
Mario Garrett, Ph.D., is a professor of gerontology at San Diego State University and can be reached at mariusgarrett@yahoo.com
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