I have long maintained that human lifespan could be attributed to different factors in different periods of life:
Birth to teens the most important factor was care—both parental and professional healthcare
Teens to middle age the most important factor was behavior
Middle age and later the most important factor was genetics
It appears that science is increasingly confirming that last part of my hypothesis if this report by David Cox at NBC News can be believed:
A person’s genes play a far greater role in likely lifespan than previously thought, according to a major new study published Thursday in the journal Science.
Using data from human twin studies, an international team of researchers arrived at the conclusion that the genetic contribution to how long we’re likely to live is as high as 55%.
This new finding is strikingly higher than previous estimates, which have calculated the role of genetics in lifespan could range from 6% to 33%. It’s likely to intrigue — and perhaps disappoint — the fast-growing community of longevity influencers and self-described biohackers touting longer lives through supplements and customized drug regimens.
The study authors said they arrived at this very different figure by separating out what they termed extrinsic mortality (defined as deaths from external factors such as accidents, homicides, environmental hazards and infectious diseases) and intrinsic mortality (deaths caused by internal biological factors such as age-related diseases, genetic mutations and the general decline of health with age).
Through treating these two categories of death separately, the researchers said they were able to get a far more accurate estimate of the relationship between genetics and lifespan. It also matches with findings regarding the role of genes in other key physiological traits: Height, body fat distribution and muscle build are all thought to be at least 50% heritable.
As regular readers of this blog may recall I am a student of my family’s history. At present I am older than my father was when he died and older than both grandfathers when they died. I have also outlived one great-grandfather and will soon outlive the other three.
I have no plans of dying in the immediate future but last year I actually felt old for the first time in my life. There may be something to this heredity stuff.
