Owning a dog could be linked to a decreased risk of cardiovascular disease (CVD) in single-person households and lower all-cause mortality in the general population, a 12-year study of Swedish canine owners suggests.

Previous research has proven pooches can be heart-healthy additions to the family through encouraging exercise and boosting social interaction, corresponding author Tove Fall and colleagues wrote in the study, published Friday in Nature: Scientific Reports. Meta-analyses have confirmed dog owners are more active—especially in poor weather—than non-owners, and the animals can act as social supports, improving an owner’s perception of their well-being. Studies have suggested the animals can be particularly helpful for elderly patients or those with mood disorders.

Still, the research isn’t without its limitations.

“Previous findings on dog ownership and the risk of CVD are conflicting,” Fall et al. wrote. “In individuals without CVD, dog ownership has been reported as inversely associated with the prevalence of cardiovascular risk factors, such as dyslipidemia, hypertension and diabetes, but other studies found absent or inconclusive associations.”

Even in such cases, the authors wrote, dog ownership has consistently been linked to improved survival in coronary artery disease patients.

Fall and co-authors drew from a nation-wide register of more than 3.4 million Swedish adults between 40 and 80 years old for their trial. The study excluded the very young due to their low likelihood of developing CVD and the very elderly for their low odds of owning a dog. The participants were followed for more than a decade, and 13.1 percent were dog owners at any given time during the study period.

The researchers found that, in age and sex-adjusted analysis, dog ownership was inversely associated with risk of heart attack, ischemic stroke, heart failure and composite CVD, as well as cardiovascular mortality and all-cause mortality. The authors adjusted their findings for education and socioeconomic index but found no major differences in the data.

Dog owners were more likely to be younger than non-owners, Fall and colleagues wrote, and were more likely to live in rural areas. They also saw higher odds of being married and having kids.

When it came to breeds, canines originally bred for hunting—like terriers, retrievers and scent hounds—were associated with a lower risk of CVD. While owning a mixed-breed dog was correlated with a higher risk of CVD, ownership of a purebred pooch was associated with a lower risk of all-cause mortality.

No matter the breed, though, Fall and co-authors wrote dogs are repeatedly proven to have a positive health effect on those living with them. Dogs can alleviate psychosocial stress, depression and loneliness, according to the study, all of which are stressors that can encourage coronary heart disease, cardiovascular death and all-cause mortality. Dog ownership has also been linked to elevated parasympathetic and diminished sympathetic nervous system activity, lower reactivity to stress and faster recovery of blood pressure after a stressful activity.

Due to the nature of these studies, though, Fall et al. wrote there isn’t enough evidence to stake any permanent claims on the research.

“Our observational study cannot provide evidence for a causal effect of dog ownership on cardiovascular disease or mortality,” they wrote. “Although careful attention was paid to adjusting for potential confounders in a set of sensitivity analyses, it is still possible that personal characteristics that we did not have information about affect the choice of not only acquiring a dog, but also the breed and the risk of CVD.”