Next step will be to examine the importance of inherited and environmental factors.
Researchers working with zebra finches at the University of Glasgow report that a good indicator of how long individuals will live can be obtained from early in life using the length of telomeres. Their paper appears online this week in PNAS.
The study is the first in which telomere length has been measured in the same individuals from early life and then repeatedly during the rest of their natural lives, said the research team. The results show that telomere length in early life is strongly predictive of subsequent lifespan.
To carry out the study, the scientists measured telomere lengths in small samples of blood cells taken at various ages in a group of zebra finches whose lifespan varied from just 210 days to almost nine years. The best predictor of longevity was telomere length at just 25 days, according to Britt Heidinger, Ph.D., from the University of Glasgow. “While there was a lot of variation among individuals in telomere length, those birds that lived longest had the longest telomeres at every measurement point,” noted Dr. Heidinger.
It is known that the variation in telomere length is partly inherited, but also varies due to variation in environmental factors such as exposure to stress, explained team leader Pat Monaghan, Ph.D., also at the University of Glasgow.
“Our study shows the great importance of processes acting early in life. We now need to know more about how early life conditions can influence the pattern of telomere loss, and the relative importance of inherited and environmental factors. This is the main focus of our current research,” she said.
The study also raises the question about if and when the day might come when diagnostics for telomere length in humans will be developed and subsequently incorporated into each person’s lifestyle/health plan.
“At present we do not have comparable studies in people that would allow us to say at what life stage telomere length best predicts lifespan,” replied Dr. Monaghan. “Telomere length in early life has not been measured in individuals whose subsequent lifespan is known. For obvious reasons, this would take a very long time. Also, there is a lot of variation among individuals, and other factors also affect lifespan. So, while it might be possible to attach a probability to having a lifespan of a particular duration based on telomere length, the realized lifespan may differ.”