Definition of 'Dog Years' Not as Simple as Multiplying by 7
THURSDAY, July 2, 2020 (HealthDay News) -- Mapping changes in the genome over time, researchers have developed a new formula to compare dog age with human age -- and it's not as clear-cut as every dog year equals seven human years.
The formula is based on chemical changes in what's known as methyl groups in the genes of dogs and humans. From that, researchers can better calculate a dog's age as it gets older, the rate of which changes over time. The finding could help scientists measure the effects of anti-aging treatments more accurately, they added.
"There are a lot of anti-aging products out there these days -- with wildly varying degrees of scientific support," said senior researcher Trey Ideker, a professor at University of California, San Diego School of Medicine.
"But how do you know if a product will truly extend your life without waiting 40 years or so? What if you could instead measure your age-associated methylation patterns before, during and after the intervention to see if it's doing anything?" he said.
Ideker and his team developed a graph to match the age of a dog with a comparable human age. And it's not a simple matter of multiplying your dog's age by seven.
For example, a 1-year-old dog is like a 30-year-old human. A 4-year-old dog is like a 52-year-old human. Then by 7 years old, the dog's aging slows, the researchers said.
"This makes sense when you think about it -- after all, a 9-month-old dog can have puppies, so we already knew that the 1:7 ratio wasn't an accurate measure of age," Ideker said in a university news release.
A limitation of the study is that it was done with only one dog breed, namely Labrador retrievers. The life spans of various breeds differ, Ideker said.
But because it's accurate for humans and mice and Labrador retrievers, Ideker thinks the clock will apply to all dog breeds.
The researchers plan to test other dog breeds to determine if the results hold up.
Ideker said he looks at his dog differently now. "I have a 6-year-old dog -- she still runs with me, but I'm now realizing that she's not as 'young' as I thought she was," he said.
The report was published July 2 in the journal Cell Systems.
For more on aging, see the U.S. National Institute on Aging.
SOURCE: University of California, San Diego, news release, July 2, 2020