Man has always strived to learn the secrets to living longer. Now it appears one of them might be the companionship of man’s best friend.
A study in Sweden has established a link between owning a dog and reduced risk of early death. The study of 3.4 million Swedes aged 40 to 80 found there was a significantly lower risk of death from cardiovascular disease or other conditions linked to early death among people who own a dog.
It was possible to carry out such a large scale study in Sweden for two main reasons. First, anyone who owns a dog must register it officially and, second, all hospital visits and treatments are meticulously recorded. This made it possible to compare national databases for dog ownership with those for hospital visits covering the period from 2001 to 2012.
The researchers found a marked reduction in the number of early deaths among dog owning households in their study, particularly from cardiovascular disease (CVD), which is the leading cause of death worldwide. More than that, they found the risk of early death from CVD and other causes was reduced by up to a third among people who lived alone if they owned a dog.
The detail in the Swedish databases even enabled them to pinpoint specific types of dog which seemed to have a more beneficial effect. Owners of traditional hunting breeds, such as terriers, retrievers and scent hounds, appeared to have the lowest risk of early death.
It would be impossible to duplicate the study in the UK, because it is not compulsory to register dog ownership here, but there is nothing to suggest that its conclusions would not be replicated. The obvious conclusion is that dog owners are more active, because they should walk their pets at least once a day, and there are several well-proven health benefits of remaining active and taking regular exercise. Even the evidence about particular breeds seems to back this up, as hunting breeds are more energetic and need more exercise than some other types of dog, such as lap dogs.
Of course it may be that people who are already more active choose to own a dog, rather than the dog forcing them to become active, but in either case there is a clear link between dog ownership and regular physical activity.
However, there might be more to the health benefits of dog ownership than physical activity alone. The Swedish study found particularly pronounced benefits for single people and since they are unlikely to all be exercising more than dog owners in multiple households, there must be something else going on. The researchers speculated that the companionship of owning a dog could alleviate psychological stress factors for single people, such as social isolation, depression and loneliness.
All these factors have previously been linked to increased risk of early death from CVD and other causes. It isn’t just that the dog is providing companionship in the home; it also means the dog owner is likely to get out and about more, meeting and interacting with other people, especially other dog walkers. There is also evidence that owning a dog helps people to recover and rehabilitate more quickly following an accident or medical procedure.
There could also be another link between dog ownership and more robust health, operating at a microscopic level. Dog owners have been found to have a different “microbiome” to non-dog owners, the “microbiome” being the collection of microscopic species which live in a person’s gut. This is because the dust and household dirt in a dog owner’s home environment is influenced by the dog, and low-level exposure to these additional bacteria can help a dog owner’s immune system become generally more resistant to infection and disease.
Senior author of the Swedish study, Tove Fall, said while it did demonstrate a link between dog ownership and reduced risk of early death, it did not set out to prove causes for that link. More specific work would be needed in order to do that. He also acknowledged that rather than dogs causing a healthy lifestyle among their owners, it could be that people who already favoured a healthy lifestyle chose to own dogs as part of it.
Reacting to the study, Dr Mike Knapton, from the British Heart Foundation, said previous studies had already shown a link between owning a dog and having a reduced risk of heart disease, but never on such a large scale as the Swedish study.
“Dog ownership has many benefits and we may now be able to count better heart health as one of them,” he said. “Whether you’re a dog owner or not, keeping active is a great way to improve your heart health.”