Look to your aunts, uncles and parents for clues to your longevity
Your chances of inheriting genes linked to longevity are highest if you come from a family with many long-lived members, researchers say. And that includes aunts and uncles, not just parents. Using databases at the University of Utah and in the Dutch province of Zeeland, investigators analysed the genealogies of nearly 315,000 people from over 20,000 families dating back to 1740. We observed . . . the more long-lived relatives you have, the lower your hazard of dying at any point in life, said study lead author Niels van den Berg. He is a doctoral student in molecular epidemiology at Leiden University in the Netherlands.
For example, someone whose parents are both top survivors has a 31 per cent lower hazard of dying than someone of the same age without such parents, van den Berg said in a University of Utah news release. Top survivors refers to people in the top 10 per cent age-wise of a group of people born within a given time period. Moreover, that persons hazard of dying is reduced, even if the parents themselves did not live to be extremely old but aunts and uncles were among the top survivors, van den Berg said.
In long-lived families, parents can therefore pass on longevity genes to their children, even if external factors prohibited them from reaching the top survivors, he explained.
The findings reinforce the idea that there really are longevity genes to be discovered in humans, van den Berg said. The study was published online Jan. 7 in the journal Nature Communications.
Researchers have long searched for genes associated with longevity, but those genes have been much more difficult to pinpoint than genes for disease, said study co-author Eline Slagboom, a professor of molecular epidemiology at Leiden University.
This research has led us to be far stricter in selecting the people in whom you have to look for those genes, Slagboom said. If you investigate a random group of people aged over 100, however exceptional they may be, its highly likely that many of them do not in fact belong to a family in which longevity is heritable, Slagboom said. Their age is probably a matter of chance, the result of a healthy lifestyle or healthy circumstances, for example during childhood, and isnt therefore reflected in their DNA.
What is the key to a long lifespan? A number of prior and ongoing projects have intensely studied centenarians (100 years old) and supercentenarians (110 years old) with hopes of unlocking genetic and/or biochemical secrets as to why a subset of humans live an exceptionally long and disease-free life. This is a highly challenging area of study in humans, given their long average lifetimes relative to the animal kingdom and the significant environmental variability that individuals experience over the course of these lifetimes.
One pathway of keen interest for lifespan modulation consists of human growth hormone (GH) and insulin-like growth factor (IGF), in which mutations in the IGF1 locus have been shown to be enriched in centenarians. Recently, in the June 16 issue of Science Advances, Ben-Avraham et al. identified a new longevity-associated allele consisting of a splice isoform of the GH receptor (GHR) lacking exon 3 (d3-GHR).
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