From an analysis of more than 3.4 million adults, researchers found that people who owned dogs — particularly those in single-person households — were at lower risk of cardiovascular and all-cause mortality over a 12-year period, compared with people who didn't own dogs.
The study was conducted by researchers from Uppsala University in Sweden, and the findings were recently reported in the journal Scientific Reports.
Dogs are one of America's favorite pets; around 48 percent of households in the United States own at least one.
It is fair to say that the majority of dog owners would consider their four-legged friends to be a part of the family; they bring us happiness and companionship, and they never fail to make us laugh with their playful antics.
However — as an increasing number of studies are starting to show — our pooches could be good for our health, too. One study reported by Medical News Today earlier this year revealed that dogs might help to alleviate childhood stress, while more recent research found that letting dogs sleep in the bedroom at night could benefit owners' sleep quality.
Research has also shown that dogs may help to increase owners' exercise levels, which could help to protect their cardiovascular health.
The new study sought to explore this association further. Specifically, it looked at how owning a dog might influence the risk of death from all causes, as well as from cardiovascular disease.
Dogs and death risk
For their study, lead junior author Mwenya Mubanga — of the Department of Medical Sciences and the Science for Life Laboratory at Uppsala University — gathered health, mortality, and dog ownership data for 3,432,153 individuals who were living in Sweden.
Information was taken from a total of seven national data sources, including the Swedish National Patient Register, the Cause of Death Register, the Swedish Twin Register, and the Swedish Kennel Club.
All individuals were free of cardiovascular disease when the data began being collected in 2001, and they were followed-up for an average of 12 years.
Compared with individuals who did not own a dog, the people in multi-person and single-person households who did own a dog had an 11 percent and 33 percent lower risk, respectively, of all-cause death.
In single-person households, dog ownership was tied to a 36 percent lower risk of cardiovascular death, while dog ownership in multi-person households was linked to a 15 percent reduced risk of cardiovascular death.
The 'most robust evidence so far'
The researchers note that their study was not designed to identify the reasons why dog ownership might lower the risk of premature death, but they have some theories.
"We know that dog owners in general have a higher level of physical activity," explains senior study author Tove Fall, also of the Department of Medical Sciences and the Science for Life Laboratory at Uppsala University, "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," she adds.
It is also unclear why people living in single-person households appear to benefit more from dog ownership. "Perhaps a dog may stand in as an important family member in the single households," Mubanga speculates.
Fall points out that the study's population-based design means that the results could potentially be generalizable to the entire Swedish population, as well as other populations who have similar dog ownership cultures.
The researchers conclude:
"Taken together, we believe our longitudinal population-wide design provides the most robust evidence so far of a link between dog ownership and health outcomes, although bias from reverse causation, misclassification, and confounding cannot be excluded."