A new study of more than 3.4 million individuals shows that dog owners have a lower risk of death due to cardiovascular disease or to other causes. The results were published today in Scientific Reports.
The study was conducted in Sweden, where every person carries a unique personal identity number. Every visit to a hospital is recorded in national databases, accessible to researchers after de-identification of data. Even dog ownership registration is mandatory. This abundance of data enabled the team to determine whether being registered as a dog-owner was associated with later diagnosis of cardiovascular disease or death from any cause.
"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. The results showed that single dog owners had a 33 percent reduction in risk of death and 11 percent reduction in risk of cardiovascular disease during follow-up compared to single non-owners. Another interesting finding was that owners to dogs from breed groups originally bred for hunting were most protected," says Mwenya Mubanga, lead junior author of the study and Ph.D. student at the department of medical sciences and the Science for Life Laboratory, Uppsala University.
"These kind of epidemiological studies look for associations in large populations but do not provide answers on whether and how dogs could protect from cardiovascular disease. 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," explains Tove Fall, senior author of the study and associate professor in epidemiology at the department of medical sciences and the Science for Life Laboratory.
"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. Thanks to the population-based design, our results are generalisable to the Swedish population, and probably also to other European populations with similar culture regarding dog ownership," adds Fall.