Chronological age does not capture ageing. We need a biological clock.
In an earlier Newsletter I discussed finding a “cure” for ageing. (Newsletter #069). Around the world teams are trying to develop ageing pharmaceuticals. These would slow ageing and extend human life. The Newsletter describes three barriers to a successful outcome. The first was the science itself. Researchers are still exploring the causes and processes of ageing. Without a deep understanding, it is impossible to design interventions.
There were two other barriers to the field. At the time ageing was not accepted as a disease. This created all kinds of administrative and funding issues. Any drug could not be authorized by regulators such as the FDA. Funding would be more difficult to get. Recently, however, the this problem was removed. The World Health Organization has classified ageing as a disease (Newsletter #218).
The second problem is more practical. How to conduct studies on life extension in a time frame that makes sense. Studies cannot wait 100 years to find out if a drug has worked. If the measure of success is “average lifespan” how many years would it take to be sure that the average had increased? Even if drugs have to be taken after the age of 60 this still means a 30-50 year wait for each study. Instead, what is needed is a way of measuring age over much shorter periods. What is needed is a clock that can measure an individual’s biological age. Progress at slowing the clock can then be assessed with and without a drug or intervention.
A New Biological Clock
A team of researchers led by Oxford University have just developed just such a clock. They used the same blood proteins that I mentioned last week (Newsletter #223 Ageing by Instalment). They had available three powerful longitudinal studies. Each tracks an individual’s health over their lifetime. Each measures multiple blood proteins. The UK Biobank data alone measures over 3000 different proteins.
They used AI on the UK data to generate an index of biological age. In the end this was based on only 204 proteins. For each individual they could thus compute a biological age. This can be compared with their chronological age. The “protein age gap” measures how fast someone is ageing. The gap was as large as twelve years between two people of the same chronological age. Some were ageing faster, others slower,
They were able to use the same algorithm in other parts of the world. They computed biological age for samples from China and Finland. Two countries that have very different lifestyles. More importantly they have different genetic make-ups to the UK.
Predicting Illness
With the UK Biobank they were able to predict serious illnesses. They could use the protein age gap to predict subsequent diseases. This included physical and mental illness. They also predicted when someone would die.
Faster ageing was indeed associated with physical frailty. With the ability to undertake common tasks. With grip strength and the ability to pick things up. The protein age gap predicted things like bone density and the occurrence of various cancers.
It has a powerful association with the onset of 18 major diseases. Diseases of the heart, liver and kidney could be predicted. So too can it predict the occurrence of multiple such diseases within one individual. The gap was associated with measures of cognitive ability. It could predict the onset of dementia.
The biological age gap could predict the likelihood of premature death. This biological clock is more powerful than its predecessors. It can predict more diseases across a wider range of diverse people and diseases.
The Power of A Biological Clock
Clocks such as this may unlock the search for a medicine for ageing. This particular clock can predict telomere length. Another measure of ageing that is based on DNA itself.
The clock also offers the opportunity for individual interventions to prevent diseases. Based on the diagnosis that the clock offers lifestyles can be changed. It could also be used to develop precision medicines.
One of principle researchers provides a key summary:
“Chronological age simply tells the passage of time rather than the ageing of our body’s functions. For some people, their biological ‘clock’ is ticking faster than others and they age faster.”
Prof Zhengming Chen, Richard Peto Professor of Epidemiology at Oxford Population Health