It all started when biostatisticians Steve and Markus Horvath at the University of California, Los Angeles agreed to participate in a study about epigenetic markers—changes to one’s DNA and gene expression—back in 2011. The study ended up revealing something unexpected: methylation patterns, which regulate tissue-specific gene expression, were able to estimate people’s chronological age give or take five years. Steve Horvath used his findings to create what’s now known as the Horvath (or pan-tissue) clock, which estimates the biological age of individual organs.
One’s biological age is quite different from their chronological age. A chronologically 45-year-old person might have a biological age of 55 if their organs have deteriorated faster than expected due to disease or unhealthy habits. Biological age essentially tells us how much time a person has left—regardless of how many candles they’re putting on their birthday cake.
Another aging clock, developed by researchers at the Yale School of Medicine, uses a person’s chronological age and several blood biomarkers to determine their biological age. Morgan Levine, who helped develop DNAm PhenoAge, claims a one-year jump in biological age means a 9 percent higher risk of death. A third aging clock called DeepMage was announced just two years ago and is said to be the most accurate to date, with an error margin of only 2.77 years.
So what is this information good for, beyond inducing anxiety and kick-starting people’s bucket lists? researchers told the MIT Technology Review aging clocks could be helpful to those who haven’t previously been in tune with their health risks. Information gleaned from aging clocks might also boost scientists’ anti-aging effortswhether medically or cosmetically motivated.
However useful in these contexts, the reliability of aging clocks is widely debated among those familiar with them. As the MIT Technology Review mentioned, some are “noisy,” with slight methylation fluctuations having the potential to produce wildly inaccurate results. It might be easier and less emotionally taxing to independently practice healthy habits than falsely be advised you’ll die soon.