Seymour Telegraph

New study sheds light upon urban myth

By David Rak

One human year does not equal seven dog years, according to a new study that suggests puppies are ‘older’ than we thought.

The findings show one-year-old puppies are about 30 in human years, and by age four, they’re about 54 — so too bad if you thought your adorable pup was the equivalent of an infant child.

In a peer-reviewed study, researchers at the University of California San Diego’s school of medicine focused on epigenetic changes to DNA — modifications that don’t change our genetic code but instead turn genes ‘on and off’.

Using 104 labrador retrievers, the researchers observed how particular molecules, methyl groups, accumulated in human genes as they aged and compared them with how they accumulated in a similar gene for dogs.

The results suggest the popular yardstick for measuring how old your dog is — if your dog is one, they’re seven human years — is wrong.

The dogs showed a much more rapid accumulation of methyl groups than humans in their first year of life, suggesting they age much faster than humans early on.

However, as time went on, the dogs aged less rapidly when compared to humans.

The result was a logarithmic relationship — a curve rising rapidly early on then gradually flattening off — between dog and human ages. For example, when a dog is one, it has the equivalent amount of methyl groups as a 31-year-old human, so its human age is 31, the study suggests.

When a dog is four, its human age is about 53, and if it’s 15, its human age is 74.

Seymour Veterinary Surgery vet Elle O’Connell said clients had always equated one human year with seven dog years, but increasingly were more aware it wasn’t that simple.

‘‘We’ve got tables we’ve worked on for a number of years that show smaller dogs age slower than big dogs,’’ Dr O’Connell said.

‘‘A table we use equates a 10-year-old big dog to an 80-year-old human.

‘‘Coming up to 30 (human) years for one dog year is more than we’d expect though — that’s probably greater than what we’ve previously used.’’

Dr O’Connell said at around six to nine months old, a dog was like a typical human teenager in many respects.

‘‘They’ve got a rapid growth phase with long gangly limbs, they can be more cheeky and less inclined to listen, just like our teenagers.’’

Dr O’Connell said research into dog ageing was important for tailoring tests and treatment such as blood tests, tests for lumps and bumps, lung and kidney function and things that whittle away with time.

‘‘Two months in our time frame can be years in a dog’s time frame, so being really proactive with your dog and talking to your vet can help.

‘‘Imagine if you were that dog.’’