People in Sweden with dogs were less likely to die than their fellow citizens without dogs over a 12-year period, according to a recent study. In Sweden, there are extensive records in national registries of citizen’s medical visits as well as from national dog registries. These sources of information allowed scientists to combine data about health with data about dog guardianship.
The study, “Dog ownership and the risk of cardiovascular disease and death—a nationwide cohort study” followed 3.4 million people between the ages of 40 and 80 who had no history of cardiovascular disease to study the relationship between having a dog and cardiovascular health. The major finding of the study was that those people who had dogs were less likely to die of cardiovascular disease or from other causes than people who did not have dogs.
It is unclear exactly why dogs are associated with better health and lower mortality. Two likely reasons are the social support that dogs provide and the increased physical activity that having a dog usually entails. It’s also possible that increased exposure to canine bacterial biomes play a role.
It’s easy to assume that having dogs is the actual cause of the increased health, but that’s not necessarily the case. Perhaps dogs are not truly protecting their guardians from ill health and death, just reflecting differences that already exists between people with dogs and those without them. For example, the people with dogs tended to live in more rural areas. It’s even possible that any differences are simply because overall, it is healthier people who are getting dogs in the first place.
The greatest difference in health between dog guardians and non-dog guardians was seen in people who live without any other humans in their household, which suggests that the social aspect is a key part of the difference. Dogs may very well protect people from health risks associated with depression, social isolation and loneliness.
Without knowing if having a dog was really the cause of the differences found in the study, it still makes sense to have a dog for health reasons—just in case!