The ends of chromosomes (telomeres) shorten with age, and this shortening may contribute to the increased risk of disease and death seen in old age; in the genetic disorder dyskeratosis congenita, for example, telomere shortening is accelerated, and patients have premature onset of many age-related diseases and early death. In the general population, however, whether people with longer telomeres live longer than those with shorter telomeres has not been tested before now.
Richard M Cawthon from the University of Utah, Salt Lake City, USA, and colleagues studied 143 individuals over the age of 60 years. When the study population were matched by age, and ranked by telomere length (done by blood assessment), those in the top half for telomere length lived four to five years longer than those in the bottom half. People with shorter telomeres were found to have higher mortality rates associated with a threefold increase in risk of death from heart disease for those in the bottom half of telomere length, and over an eightfold increased risk of death from infectious diseases for people in the bottom quartile of telomere length.
Richard Cawthon comments: "This is the first research study showing that telomere length is predictive of survival in humans. It supports the hypothesis that telomere shortening is a fundamental process of ageing, contributing to mortality from multiple age-related diseases. If this is correct, then it may be possible to extend the duration of healthy adult life using medical interventions that maintain telomere length."
Contact: Dr Richard M Cawthon, Department of Human Genetics, University of Utah, 15 N 2030 E Street, Room 2100, Salt Lake City, UT 84112, USA; T) 801-585-5520, F) 801-581-7796, E) rcawthon@genetics.utah.edu
Journal
The Lancet