In the season 5 finale of The Kardashians, the family took a commercially available blood test to discover how fast their bodies were ageing. It came as little surprise, given their privileged lifestyles, that the reality TV stars were said to be ageing more slowly than most mortals of the same age. Khloé, then 39, found she had a biological age of 28. Cue whoops of joy and much smugness.

The Kardashians join a growing list of celebrities who have taken similar tests and then crowed about their “biological ages”. Now, there’s a new test on the block.

Chronological age is the number of candles on your birthday cake. Biological age is a measure of the health of your cells and organs. The new method, devised by Vadim Gladyshev from Harvard Medical School and colleagues, not only provides a measure of biological ageing, but also a “time to death”. Who wants to hand over a sample for analysis? Definitely not me.

Researchers have been devising so-called molecular clocks to estimate biological age for more than a decade. The problem they are trying to solve is that there is no objective measure for age – humans don’t have tree rings – so researchers pick something that they can measure, that seems to change with age and that may also say something about the........

© The Guardian