Owning a cat could reduce your risk of a heart attack by nearly one third, researchers told delegates of the American Stroke Association’s International Stroke Conference in New Orleans last week. The finding provoked a mixed reaction from heart experts and veterinarians.

The finding was the main result of a 10 year study of more than 4,000 Americans by researchers at the University of Minnesota’s Stroke Institute in Minneapolis. Executive director of the Institute, Dr Adnan Qureshi, who is also senior author of the study, was reported by US News & World Report to have said:

“For years we have known that psychological stress and anxiety are related to cardiovascular events, particularly heart attacks.”

Qureshi said having pets probably helped to relieve stress. The researchers said dogs probably had a similar effect, but there weren’t enough dog owners in the study to show this conclusively. Previous research has linked contact with pets to heart benefits, they said.

Qureshi and colleagues extracted data on 4,435 Americans aged 30 to 75, from the second National Health and Nutrition Examination Study that took place from 1976 to 1980. 2,435 of the participants were current or former cat owners, while the remaining 2,000 had never had a cat.

Using the main outcome as death from all causes, including stroke and heart events, the researchers found that over a 10 year follow up period, cat owners showed a 30 per cent lower risk of death from heart attack compared to non cat owners.

Qureshi, who own a cat called Ninja, said they had expected to see an effect, because the theory was plausible, but the size of the link was a surprise.

Someone who was not surprised by the findings was Kathie Cole who presented the results of a study to the American Heart Association in 2005 that showed contact with dogs helped improve heart and lung function in people with heart failure. Cole is a clinical nurse at the University of California Los Angeles (UCLA) Center and School of Nursing. She told US News & World Report:

“I would be inclined to think that any animal that is perceived as meaningful to a person in a positive way would have health benefits.”

She mentioned other research that suggested pets had a calming effect. Unfortunately, the opportunity to have this “low cost” stress relief is denied to many potential heart patients who live in apartment blocks and nursing homes where pets are not allowed.

Qureshi said this research:

“Opens a whole new avenue or intervention that we hadn’t looked at before, one that can be made at the public level.” And there appear to be no risks with this approach, unlike drugs or surgery, he added.

Others would disagree, saying that such findings are not proof of a causal link, only that a link between cat ownership and lower heart attack risk exists. Qureshi admits this, said a report in ABC News. The link could be to the personality and lifestyle of cat owners and not to the fact they have a cat.

“Maybe cat owners tend not to have high-stress personalities, or they are just the type of people that are not highly affected by anxiety or high-stress situations,” he said.

Qureshi and colleagues did not analyse the personality traits of cat owners and could therefore not shed light in this area.

Another reason to be sceptical, other experts told ABC News, is that other studies have shown quite different results. One for example, published in the American Journal of Cardiology in 1995, showed that while dog owners had a higher chance of surviving a heart attack, cat owners had a reduced chance. Director of the division of cardiology at the University of Miami, Dr Robert Myerburg, said this made sense because many people are allergic to cats, and not to dogs. He said he was surprised by this latest study.

Veterinary experts however, put across another plausible argument for why cats might bring more stress relief than dogs. Technical vice-president and veterinary pathologist at ARUP Laboratories in Salt Lake City, Utah, Lawrence McGill, said it was probably because cats are lap animals that want to be petted, and it is the petting that brings down the stress levels, and heart rate and blood pressure too, in many cases.

On the other hand, said McGill, dogs need hands on attention, which could actually raise the owner’s stress. When you get home from work the dog demands attention, you have to take it for a walk, dogs need to be fed according to a routine, whereas cats can practically take care of themselves.

The American Veterinary Medical Association estimates there are about 72 million pet dogs and 82 million pet cats in the US.

Sources: US News & World Report, ABC News.

Written by: Catharine Paddock, PhD