Length of DNA strands can predict life expectancy

The length of strands of DNA in patients with heart disease can predict their life expectancy, a new study has claimed.
Researchers from the Intermountain Heart Institute who studied the DNA of more that 3,500 patients with heart disease, were able to predict survival rates among patients with heart disease based on the length of strands of DNA found on the ends of chromosomes known as telomeres.
The longer the patient's telomeres, the greater the chance of living a longer life.
The new study, presented at the American College of Cardiology's Annual Scientific Session in San Francisco has shown that telomere length can be used as a measure of age, but these expanded findings suggest that telomere length may also predict the life expectancy of patients with heart disease.

Telomeres protect the ends of chromosome from becoming damaged. As people get older, their telomeres get shorter until the cell is no longer able to divide.
Shortened telomeres are associated with age-related diseases such as heart disease or cancer, as well as exposure to oxidative damage from stress, smoking, air pollution, or conditions that accelerate biologic ageing.

"Chromosomes by their nature get shorter as we get older," said John Carlquist, director of the Intermountain Heart Institute Genetics Lab.
"Once they become too short, they no longer function properly, signalling the end of life for the cell. And when cells reach this stage, the patient's risk for age-associated diseases increases dramatically," Carlquist said.

Carlquist and his colleagues tested the DNA samples from more than 3,500 heart attack and stroke patients.
"Our research shows that if we statistically adjust for age, patients with longer telomeres live longer, suggesting that telomere length is more than just a measure of age, but may also indicate the probability for survival. Longer telomere length directly correlate with the likelihood for a longer life-even for patients with heart disease," said Carlquist.
They drew on two unique resources that offer unparallelled opportunity for researchers to study the effects of telomere length and survival rates of heart patients.
An archive of peripheral blood DNA samples collected from almost 30,000 heart patients, with as much as 20 years of follow-up clinical and survival data.