A new study on human ageing could open the door to affecting people's life spans, a genetics professor says.
The study, of nearly 1000 people aged 38, found their biological ages varied from under 30 to nearly 60 .
The participants were all part of the long-running Dunedin Multidisciplinary Study, tracking people since birth in 1972-73 to the present.
Although Associate professor Peter Dearden, from Otago University, was not directly involved in the study he said it had been difficult to measure ageing in the past.
He said that had prevented scientists from applying to humans ways they use to extend the life span of other organisms.
"But the real breakthrough here is that we can measure it, and if we can measure it, we can actually see if we can have any effect on ageing, maybe that it's impossible, but at least now we can gather that evidence."