For anyone who has ever owned a dog is very much familiar with the “dog years” concept. This is where one dog year is about the equivalent of seven human ones. While employing this metric conversion, a 2-year-old dog would be equal to a high school freshman, whereas a 10-year-old dog is as old as an assisted living patient.
However, researchers with the University of California, San Diego have used DNA in order to come to a more data-based measurement on a dog’s age.
The paper was published on the preprint server bioRxiv and is based on the finding on DNA methylation – which is a process in which molecules called methyl groups to attach themselves to DNA and serve as an indicator of aging.
Generally speaking, the older living creatures get, the faster the rate of methylation. In the study, 104 Labrador retrievers were examined, and the study subjects ranged from 1-month to 16-years-old. The results of their DNA methylation were then compared to human profiles. The results showed that the rate of methylation tracked closely between young and old dogs had similar rates to those between young and old people – proving that both adolescent and mature dogs experienced more accelerated aging.
So how did they figure out the recommended formula for comparing dog and human aging? Simply by multiplying the natural logarithm of a dog’s age by 16, then adding 31. So that 2-year-old dog isn’t the same age as a 14-year-old, but rather a 42-year-old. But don’t worry about dogs aging too rapidly as methylation slows considerably in mid-life. This means a 5-year-old dog is approximately the same age as a 57-year-old human, or a 6-year-old dog is nearing 60 human years. So that is a subtle difference. And when they reach 10-years-old, a dog would be closer to 70.
There is also the matter of different breeds aging at slightly different rates. So the formula might not be completely foolproof as only Labs were studied. The work is still waiting to be peer-reviewed, but it seems to offer a somewhat promising glimpse into how our pets really age.