We have already discussed the difference between chronological and biological age.
To summarize: scientists invented a whole range of different indicators that help us discern between how many birthdays we've had (our chronological age) and the actual biological age of our cells.
These biological age detectors can predict future health, as well as the chance of age-related diseases and physical functioning. Here, we look at three different types of ageing biomarkers:
- Biochemical tests: these are tests that measure the molecules, hormones, and proteins in your body. They are generally part of tests you might get from a doctor when you're evaluated for a disease such as heart disease, diabetes, or high blood pressure. These are probably the best known tests, and are the most commonly done, but they are mostly thought of as diagnostic tests, rather than ageing biomarkers. However, since ageing is the biggest risk factor for a multitude of diseases, measuring these is a good proxy for ageing itself.
- Functional tests: these are tests that directly test some aspect of physical or physiological functionality. Examples include how long it takes someone to walk 100 metres, or what their VO2 max is. These tests are a favourite with many researchers because they give us direct insight into the level of functional decline associated with ageing. Indeed, many argue that there is little use for some of the other types of tests if you cannot pair it to some functional biomarker which tells us how ageing has actually affected the way a person experiences their day to day life.
- Epigenetic biomarkers: as we age, our epigenome changes in a predictable way. Scientists have studied these changes and used them to create the so-called 'epigenetic clocks'. These clocks measure the amount of modifications to DNA, such as methylation, and link these to specific conditions of ageing. The epigenetic clocks are amongst the most accurate biomarkers of ageing, however there is still open debate about the meaning of an accelerated or reversed clock.
- Non-epigenetic tests focused on ageing: these are markers that have also been associated with the ageing process, but are not as popular as the famous epigenetic clocks. Examples are telomere length, and the tests measuring the accumulation of cellular or molecular damage, such as those caused by advanced glycosylation end-products.
To achieve a highly accurate result, the best option would be to combine different biomarkers assessments, which will reflect different processes in the body.
The ageing field is still in search of gold-standard biomarkers, and new developments are being made regularly. The key message from UDA is that, however you choose to measure it, we're there with you to support healthy ageing!