Dog ownership leads to lower risk of cardiovascular disease

Dog owners have a lower risk of death due to cardiovascular disease, according to an Uppsala University study.

Cardiovascular disease is the main cause of death worldwide, and in 2016 was responsible for 45 percent of deaths in Europe. Dogs may be crucial in lowering cardiovascular risk by offering social help and encouragement for physical activity.

A meta-analysis of 11 observational studies discovered that dog owners walk more and are more engaged in exercise than non owners. Two studies found alterations in physical activity when people had dogs.

An additional study found that dogs help owners maintain physical activity during bad weather.

Previous studies on dog ownership and the dangers of cardiovascular disease are contradictory. In people without cardiovascular disease, dog ownership was inversely linked with cardiovascular risk aspects, such as high blood pressure and diabetes. Other studies discovered nonexistent or unclear links.

Researchers intended to explain the link between dog ownership and cardiovascular disease risk by inspecting over 3.4 million Swedish adults over 12 years. The study was divided into the national cohort and twin cohort.

Swedish residents who were aged between 40 and 80 years on Jan. 1, 2001 were allowed to participate in this study. This was the selected age range because researchers wanted to eliminate younger people, who were at a small risk of cardiovascular disease, and the elderly, who had a low chance of owning a dog. Residents were recognized using the Total Population Register, which encompasses information on birth, migration, changes in citizenship, civil status and death for all Swedish citizens.

Researchers then duplicated this review in the “Screening Across the Lifespan Twin Study,” a sub-study of the Swedish Twin Register, for the twin cohort. The Swedish Twin Register is a longitudinal study of twins born in Sweden. The final analysis included 3,432,153 people in the national cohort, and 34,202 people in the twin cohort.

For the national cohort, researchers obtained death statistics from the Cause of Death Register and incident disease data from the National Patient Register from Jan.1, 2001 to Dec. 31, 2012. Analyzing death statistics up to Dec. 31, 2014 was allowed for the twin cohort. Socioeconomic variables were obtained from the Register of the Total Population.

Basic variables included sex, year of birth, country of birth and educational attainment. Researchers also looked at marital status, presence of children in the home, area of residence and annual household income. For the twin cohort, no demographic statistics were available.

Researchers used self-described variables including body mass index, physical activity, employment status, type of accommodation, physical impairment, need of assistance for typical daily activities and socioeconomic index.

As of Jan. 1, 2001, every dog in Sweden is mandated to have a distinct identifier, such as an ear tattoo or subcutaneous chip, filed at the Swedish Board of Agriculture. The Swedish Kennel Club has also been filing information on dog owners’ private identity numbers since 2001.

In the study, dog ownership was recognized if the owner registered with these two organizations or had a partner reported as a dog owner in these two organizations.

In the national cohort, researchers found that ownership of dog breeds initially bred for hunting, such as terriers, retrievers and scent hounds, were linked to a low risk of cardiovascular disease. Dog ownership was inversely linked with vulnerability to heart failure and cardiovascular disease.

In the twin cohort, researchers found that dog ownership is linked to a reduced risk of cardiovascular disease in single households, and a reduced risk of cardiovascular disease and all-cause death in the general population. Similar to the national cohort, the twin cohort revealed that ownership of hunting dog breeds is linked to a low risk of cardiovascular disease. Ownership of all purebred breeds was linked to a lower risk of all-cause death.

Dog ownership can reduce cardiovascular risk by diminishing social isolations, depression and loneliness. These stress factors trigger coronary heart disease and cardiovascular death. Dog owners also experience a quicker recovery from high blood pressure and physically strenuous tasks, and pursue outdoor recreation for enjoyment more than people without dogs.

As of press time, this set of studies is the largest analysis of the link between health and dog ownership that exists.