Aging clocks are the current frontier in longevity science. In order to address the causes of aging it is important to first understand how well a person is aging from a biological perspective (i.e. your biological age). Having a biomarker of aging that can accurately predict your current biological age is a necessary anchor against which we can measure the effectiveness of lifestyle or medical intervention strategies. That’s the objective of aging clocks, also known as epigenetic clocks. These clocks are based on measuring the effects of a process known as DNA methylation which takes place in specific parts of DNA strands (CpG sites or islands) during the expression of genes (i.e. the process turning them on and off). While that sounds complicated, the key insight is that methylation is a cumulative process that has proven to be a strong predictor of lifespan and healthspan across many tissues. The evolution of aging clocks has been greatly advanced by the availability of computing power as well as machine learning and deep learning models. The first generation of clocks were developed by Gregory Hannum and Steve Horvath and analyzed data from 71 and 353 CpG sites, respectively. The second generation clocks such as PhenoAge and GrimAge look at 513 and 1030 sites, respectively. The current generation such as Chronomics and GlycanAge are using the latest sequencing technology to analyze a much larger number of data points (although the latter uses glycans as a target of analysis). These three generations have all occurred in the last 8 years, which gives you a sense of how fast the science is advancing.
What next: So, should you run out and get your biological age measured? It depends on where you are in your health journey. Reasons you should wait: (1) the latest tests are not cheap (although NBT offers PhenoAge as part of their package, see above); (2) the technology hasn’t
“hardened” yet, and better clocks may be coming; (3) there are many lifestyle adjustments you can make that you know will improve your biological age without needing to know what it is. Reasons to do it: (1) Having the data: unlike DNA sequencing which you need to do only once, your epigenetic picture will change over time and the deltas can tip you off as to the evolution of chronic diseases. (2) if you are the personality type that gets motivated by having a benchmark to improve against, it might be worth it.