Among the records kept by the Swedish government on its citizens are dog ownership, the number of individuals in a household, and cause of death. These gave researchers a unique opportunity to examine the association of dog ownership on mortality in over 3 million adults (13% of whom owned dogs), as well as how living alone or in a multiperson household might influence this relationship. In light of earlier studies suggesting a positive benefit of dog ownership on physical fitness and since cardiovascular disease is the leading cause of death worldwide, the researchers also examined whether dog ownership was associated with deaths from cardiovascular disease specifically.
Their analysis revealed that dog owners showed a 20 percent reduction in risk of death from all causes and a 23 percent reduction from cardiovascular disease compared to non-owners. This association remained when education and socioeconomic status were statistically taken into account, and did not differ according to sex. The researchers also looked at the impact of age attained by participants and found that the reduction in risk of mortality was largest among those who passed away between age 70 to 90.
The most dramatic finding was the difference between dog owners who lived alone compared to those living with others. Those living alone had a 33 percent reduction in overall risk, while those in multiperson households had only an 11 percent risk reduction. While there may be alternative explanations (such as household members’ varying degrees of attachment to or participation with the dog), this large risk discrepancy suggests that the social companionship of having a dog could have significant survival benefits for those living alone.
Lastly, this study looked at how dog breed affected this risk, and found that pointer and hound owners showed the greatest reduction in risk. Owners of mixed breed dogs showed the least, for reasons that remain unclear.