When considering longevity, what role does your overall health play as opposed to the genetics of your family members? If you come from a long line of centenarians, does that mean that you can slack off on eating more vegetables and less red meat — or does the lifespan of one’s ancestors not really factor in to your own life expectancy? Based on the results of a recently-published study, the answer is “a little of each” — but it also makes clear how significant a role genes can play in extending one’s life.
In the new study, published this week in Science, the authors note that the hereditary aspects of longevity have long been beloved to be between 20% and 25%. Their findings suggest that genetics play a much larger role. Or, as they phrase it, “heritability of human life span due to intrinsic mortality is above 50%.”
What is responsible for the gulf between these two figures? The paper’s authors argue that the older estimates were “confounded by extrinsic mortality — deaths caused by extrinsic factors such as accidents or infections.” They went on to point out that the lower estimate was neither in line with other heritable characteristics in humans nor did it correspond to the frequency of longevity being heritable in mice.
The researchers explored the role that extrinsic mortality — defined here as “deaths caused by factors originating outside the body, such as accidents, homicides, infectious diseases and environmental hazards” — played in mortality. They found that this created a plateau between the ages of 20 and 40, and also determined that extrinsic mortality had declined over time. This was a significant finding, given that a number of existing studies drew on records of people born before the 20th century.
New Study Has Plenty to Say on Wealthy Americans’ Longevity
And how it compares to that of their European counterpartsAs one of the study’s co-authors, Ben Shenhar, told Max Kozlov at Nature, these findings do not mean that people with long-lived relatives get a pass on taking care of themselves; instead, he emphasized the role of lifestyle decisions in overall health. But there’s also more to learn. “There is much to be learnt from the genetics of ageing, if we can understand what genes are responsible for healthy ageing,” Shenhar told Nature.
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