Telomere Length Can Predict Life Expectancy

Researchers at the University of East Anglia have come up with a novel technique to predict the biological age and life expectancy of an individual by measuring the DNA.

They analyzed the length of the chromosome caps, known as telomeres, in a 320-strong population of Seychelles Warblers on a small isolated island. Their blood samples were collected twice a year and the telomere length analyzed.

The study highlights that the duration at which the telomeres shorten with age differs drastically in humans. Shorter telomeres at any age are associated with an increased risk of death.

Located at the end of the chromosomes, telomeres act as protective caps in order to prevent the genes close to end of the chromosome collapsing. Its length is a better indicator of future life-expectancy than actual age and may, therefore, be an indicator of biological age.

This 20-year research is the first of its kind that measures telomeres across the entire lifespan of individuals in a wild population.

"Over time these telomeres get broken down and become shorter. When they reach a critical short length they cause the cells they are in to stop functioning. This mechanism has evolved to prevent cells replicating out of control -- becoming cancerous. However, the flip side is that as these zombie cells build up in our organs it leads to their degeneration -- aging -- and consequently to health issues and eventually death," lead researcher Dr Richardson said,

The research team investigated whether, at any given age, the telomere lengths could predict imminent death. "We found that short and rapidly shortening telomeres were a good indication that the bird would die within a year. We also found that individuals with longer telomeres had longer life spans overall," informed Dr Richardson.

The study is being published Nov 20 in Molecular Ecology.

"It would be virtually impossible to do such a study in humans," said Dr Richardson. "For one thing it would take a very long time to study a human lifespan. Also in humans we would normally, quite rightly, intervene in cases of disease, so it wouldn't be a natural study.

"We found that telomeres are linked to body condition and reflect the history of oxidative stress that has occurred within an individual's lifetime. The healthier you are, or have been, the better telomeres you have. But it's hard to know whether this is a consequence of being healthy, or a cause.

All these stresses do damage to our bodies. You hear people saying 'oh they look like they've had a hard life'. This is why. A shortened telomere shows an accumulation of damage life has done to you."