6 February 2015

We count our age in calendar years, but our bodies may not be counting the same way.

We count our age in calendar years, but our bodies may not be counting the same way.

Using a biological clock that compares the ageing of a person’s DNA to their actual age, QBI researchers at UQ have found some clear signals to life expectancy.

Professor Naomi Wray said the study found that people with a “biological”, or DNA, age greater than their true age were more likely to die younger, compared to those whose biological and true age were closely matched.

“Last year, it was discovered that from a simple blood sample it is possible to predict a person’s age with a high degree of accuracy,” Professor Wray said.

“But it is not totally accurate, and some people’s predicted or ‘biological’ age is higher than their actual age and vice versa.”

“Our study showed biological age really does seem to be tracking biological wear-and-tear.”

The QBI research, undertaken with the UQ Diamantina Institute and institutions in Scotland, Australia and the United States, used data from four independent studies that sampled almost 5000 older people, of whom about 10 per cent died in the following 14 years.

Each participant’s biological age was measured from a blood sample at the outset. The research showed that those with a higher biological age compared to actual age had an increased risk of death.

All four studies found the same pattern, with death linked to accelerated biological changes to DNA.

Professor Wray said the study could not look at what caused the DNA to change at an accelerated pace, nor was it an accurate predictor of death for an individual person.

“However, it’s an important clue for future research in the study of cellular ageing,” she said.

“What we’re seeing could be caused by environmental, lifestyle, genetic predispositions, or a combination of all these factors.”

The QBI’s Dr Allan McRae, who conducted analyses for the study, said biological ageing was measured by following DNA changes caused by a process known as methylation.

“Methylation affects whether genes are turned on or off, which has important repercussions for conditions such as disease susceptibility, so it makes sense that the biological clock speeding up has impacts on how we age,” Dr McRae said.

DNA methylation age of blood predicts all-cause mortality in later life is published in the journal Genome Biology.

Media: Darius Koreis, +61 7 3346 6353, d.koreis@uq.edu.au