They may be man’s best friend, but a new study suggests dogs can do much more.

Scientists researching a link between dog ownership and cardiovascular health found friendly pooches also lower risk of death from heart disease and other ailments.

The team from Uppsala University in Sweden analysed data from 3.4 million Swedes aged 40 to 80 by combing through a national database of hospital visit records and dog ownership registrations.

A 12-year follow-up revealed dog owners had “a 33% reduction in risk of death and 11% reduction in risk of cardiovascular disease” compared with non-owners.

The researchers put this down to the dogs acting as a “protective factor” – especially for people who live on their own.

Study author Mwenya Mubanga, a PhD student at Uppsala University, said: “A very interesting finding in our study was that dog ownership was especially prominent as a protective factor in persons living alone, which is a group reported previously to be at higher risk of cardiovascular disease and death than those living in a multi-person household.

“Perhaps a dog may stand in as an important family member in the single households.

“Another interesting finding was that owners of dogs from breed groups originally bred for hunting were most protected.”

The researchers also said that aside from physical activity, owning a dog might also contribute to a person’s wellbeing by increasing social contact or possibly changing gut bacteria.

Senior study author Tove Fall, associate professor at Uppsala University, said: “We know that dog owners, in general, have a higher level of physical activity, which could be one explanation to the observed results.

“Other explanations include an increased well-being and social contacts or effects of the dog on the bacterial microbiome in the owner.”

But Fall says their research does not show how dogs protect their owners from cardiovascular disease and other causes of death.

She added: “There might also be differences between owners and non-owners already before buying a dog, which could have influenced our results, such as those people choosing to get a dog tending to be more active and of better health.”

The results are published in Scientific Reports.