DOGS DON’T KEEP YOU YOUNG.

The first thing to make clear is, Richard Watt is a dog lover. He has a beautiful black Labrador retriever, name Tilda (“as in Swinton”). She’s a year old, and “delightful.” And, Watt hopes, “not too upset about this paper.”

According to a new analysis by Watt and his coauthors, owning a dog or any other pet may not, contrary to what others have reported, help humans live longer lives.

The study is based on more than 8,700 seniors in England, one-third of them pet owners. Researchers looked at whether owning a pet had an effect on 11 different and widely used biomarkers of aging — from walking speed, grip strength, lung function and markers of inflammation in the blood, to memory and cognitive functioning.

Overall, they found pet ownership doesn’t appear to slow the rate of aging.

Compared with nonowners, dog companionship was associated with somewhat slower times walking a few metres, and a longer time to rise out of a chair, the researchers report in the British Medical Journal (though dog owners did seem to have marginally better lung function). Cat owners were more likely to fail a leg raise test than people in the other pet ownership groups. Pet ownership, whether dog, cat, hamster or other companion, was “essentially unrelated” to immune functioning. And, no apparent association was found between any type of pet and memory, or symptoms of depression.

“The companionship of creatures great and small seems to confer essentially no relation with standard physical and psychological biomarkers of aging,” the researchers concluded.

The finding, said Watt, “was a surprise, a real surprise.”

“There’s some evidence that there is a protective effect,” said Watt, of the department of epidemiology and public health at University College, London. “As a pet owner, I can see the benefits of walking dogs, the emotional companionship a dog provides, as well as the interaction with other pet owners while out and about,” he said.

While the pathways seemed clear, “our results did not confirm our hypothesis (that pets) are a protective factor” against human aging, Watt said.

The findings held after the researchers took weight, smoking, alcohol, physical activity, social isolation and loneliness and other factors into account. The results also held true for both male and female pet owners.

The findings are wildly out of sync with numerous papers on the supposed health benefits of owning a pet.

As recently as November, Swedish researchers who scoured national registries of more than 3.4 million Swedes aged 40 to 80 found that dog owners had a lower risk of death due to cardiovascular disease during the 12-year followup.

The Swedish findings were especially strong for people living alone: single dog owners had a 33 per cent reduction in risk of death, and 11 per cent lower risk of heart attack over the study period, compared with single non-owners.

In 2013, the American Heart Association concluded pet ownership — particularly canine companionship — is “probably associated” with a lower risk of cardiovascular disease, the No. 1 cause of death globally.

However, the heart doctors warned that given that most studies were not randomized, it couldn’t be said with any great degree of confidence whether the reduction in the risk of heart disease and stroke is cause and effect, or coincidental.

Watt and his group used data from the English Longitudinal Study of Ageing, an ongoing study of men and women who, when recruited in 2002-03, were aged 50 or older and living in England.

Their analysis was based on 8,785 people that, in 201011, were asked “do you keep any household pets inside your house/flat?”

A third owned a pet (18 per cent a dog, 12 per cent a cat and three per cent some other animal).

Overall, they found no evidence of a clear association of any type of pet ownership and the various biomarkers of aging.

Again, it doesn’t prove cause and effect.