SAN DIEGO, Calif. — How old is your dog in human years? It’s a pretty easy question to answer, right? Dog owners typically abide by the age-old “multiply by 7” method, but a new study says that’s just a myth. Instead, researchers from the University of California San Diego School of Medicine say they have a formula which more accurately measures the age of your beloved pooch.
It turns out the “one dog year equals seven human years” rule-of-thumb is flawed because dogs don’t age at the same rate as humans. The study says canines age much faster when they’re young, but then slow down at about seven years-old.
“This makes sense when you think about it — after all, a nine-month-old dog can have puppies, so we already knew that the 1:7 ratio wasn’t an accurate measure of age,” says study author Trey Ideker in a statement.
Epigenetic clock reveals a dog’s ‘human’ age
The study, published in Cell Systems, looks at the “epigenetic clock.” That clock determines the age of a cell based on chemical processes like methylation, which influences whether the body’s genes are switched on or off.
Ideker says changes in epigenetics give scientists clues into how old your genes are, just like the wrinkles in a person’s face. The researchers add epigenetic studies have already been done with people and mice, but co-author Tina Wang suggested trying the process on dogs.
“We always look at humans, but humans are kind of boring,” Ideker explains. “So she convinced me we should study dog aging in a comparative way.”
The researchers worked with dog genetics experts to examine the blood of 105 Labrador retrievers. Their work has created a new scale which shows a one-year-old dog’s genes are already closer to a 30-year-old human. As a dog’s aging starts to slow, a four-year-old pup is similar to a 52-year-old person. By the time a dog is in their teens, they’re closer to a 70-year-old person instead of a 100-year-old like the old system suggests.
Fighting the aging process properly
The study says tracking the age of dogs (and humans) using methylation gives scientists a way of really knowing if de-aging products are actually working.
“How do you know if a product will truly extend your life without waiting 40 years or so?” asks Ideker. “What if you could instead measure your age-associated methylation patterns before, during and after the intervention to see if it’s doing anything?”
Researchers say one drawback from the results is that the study only tested Labrador retrievers. Ideker and his team plan to test other breeds to see if their new scale for “dog years” stays consistent.
The study adds that since studying epigenetics has been accurate for both mice and humans in the past, the results for dogs should apply to every breed of man’s best friend.
This article was first published on July 3, 2020.