Can pets be good for your health? Possibly yes, a study suggests.

U.S. women over age 50 and generally healthy were less likely to die of cardiovascular events like stroke if they had a cat or dog, the researchers found.

After accounting for the increase in physical activity required of dog owners, owning a cat instead of a dog was still tied to a lower risk of death from stroke.

The researchers studied almost 4,000 adults age 50 and older without major illnesses who participated in the National Health and Nutrition Examination Survey (NHANES) in 1988 to 1994 and who reported their pet ownership.

Participants also answered questions about physical activity, weight and height, cigarette smoking and other health risk factors. More than half were overweight or obese.

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About 35 percent of people owned a pet, most often a dog. Pet owners tended to be younger, more often were married, and more often were white.

According to the National Death Index, as of 2006, 11 of every 1,000 non-pet owners had died of cardiovascular disease, compared to about 7 of every 1,000 pet owners.

Specifically for stroke, male pet owners were just as likely to have died, but female pet owners were about 40 percent less likely to have died of stroke.

Most of this association was driven by cat ownership, according to results in High Blood Pressure and Cardiovascular Prevention.

"Anecdotally, we believe that walking a dog is good for heart, reducing life pressure and blood pressure as well," said senior author Jian Zhang of the Jiann-Ping Hsu College of Public Health at Georgia Southern University in the U.S.

"I strongly believe that putative benefits of keeping a dog have not yet fully translated into reality, and we found that pet owners did not walk pets, certainly, dogs, more often than others," Zhang said. "This explains why owning a dog did not reduce CVD mortality among dog owners."

Cat owners may have a personality that protects their hearts, rather than cats actually having a concrete effect on heart health, he said.

"We are short of overall assessment of the associations of companion animals with human health, and our study should not be interpreted to encourage more people to own pets, either dog or cat," Zhang said. "Pets are good, but have to be kept responsibly."

"In my study, there was a tendency for pet owners to have a higher risk of dying," said Dr. Richard F. Gillum of Howard University College of Medicine in Washington D.C., who was not part of the new study but did study the same NHANES surveys.

Most findings show no association between pets and survival, he said.

"Data from NHANES are really inadequate to settle the question, since one can only determine there was a pet in the household, but not the number of pets or whether the study participant was the owner, cared for it or interacted with it," Gillum said. "So we need to wait for better studies before making any firm conclusions about pets and survival among their owners."

"Even if there were a reduction of death from stroke among women with cats, of what importance is that in public health terms if they are just as likely to die as other women, just from another cause," he said.