Man's best friend: Owning a dog linked to lower death rate, study says The new study is the largest to date on the health implications of owning a dog.

 -- Owning a dog is associated with a significantly lower risk of cardiovascular disease and lower death rate, according to a comprehensive new study published by a team of Swedish researchers on Friday in the journal Scientific Reports.

The scientists followed 3.4 million people over the course of 12 years and found that adults who live alone and owned a dog were 33 percent less likely to die during the study than adults who lived alone without dogs. In addition, the single adults with dogs were 36 percent less likely to die from cardiovascular disease.

"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 multiperson household," Mwenya Mubanga, a Ph.D. student at Uppsala University in Uppsala, Sweden, and the lead junior author of the study, said in a statement announcing its findings.

The link between dog ownership and lower mortality was less pronounced in adults who lived either with family members or partners, but still present, according to the study.

"Perhaps a dog may stand in as an important family member in the single households," Mubanga added. "Another interesting finding was that owners [of] dogs from breed groups originally bred for hunting were most protected."

The study, which is the largest to date on the health implications of owning a dog, suggested that dog owners may have a lower rate of mortality and cardiovascular disease because dog owners walk more.

"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," Tove Fall, a senior author of the study and a professor at Uppsala University, said in a statement.

"We know that dog owners in general have a higher level of physical activity, which could be one explanation to the observed results," Fall added. "Other explanations include an increased well-being and social contacts or effects of the dog on the bacterial microbiome in the owner."

Fall added that because all participants of the study were Swedish, the results most closely apply to dog owners in Sweden or other "European populations with similar culture regarding dog ownership."