It’s Better Going With the Dogs

Dogs Can Help You Live – and Live Longer

Can living with a dog improve your life?  It certainly appears canine companionship might extend it.

The results come from a Swedish study at Uppsala University which used the longstanding public health advantages of that country.  All the Swedish population between the ages of 40-80 were surveyed.  Out of those 4 million people, 3.4 million who demonstrably did not have major heart disease and had remained in Sweden  were followed a full 12 years.  At the same time, 41,000 Swedish twins were studied. 

As was everybody’s dog ownership. 

Since 2001 every Swedish pooch has either an ear tattoo or subcutaneous chip implant, and is registered with the national Board of Agriculture.  All certified pedigreed dogs are registered with the Swedish Kennel Club.  The researchers estimated 83% of dogs were somewhere in the public record. d.

Combine human and dog registries with far better data than most countries can muster and gives you a pretty good idea of what happens when humans go with the dogs.

What Did They Find?

The biggest effect occurred on overall and cardiovascular mortality.   Owning a dog cut death rates in both arenas.  However, rates of heart attack and heart failure were only decreased for certain groups.

Who Benefitted the Most?

Singletons.  People who lived alone benefitted the most from having dogs.  Another group that did particularly well were the elderly.

Did Everybody Benefit?

Apparently not.  The data from the 41,000 twins did not show much of a mortality decrease.   The authors thought that was due to less usable data on lifestyle in this group, and the smaller sample size.

Did the Type of Dog Matter?

Yes.  Pointers showed the lowest overall odds ratio of mortality (.6 versus the expected 1.)  Breeds bred for hunting showed overall better results.  Mixed breeds showed the least effect.

Does Everyone Agree With The Results?

No. Other studies have been equivocal.  The large Norwegian HUNT trial did not show an improvement in mortality.  That was a cohort study, different from a registry study like the Swedish one, where the data is mandated by law.  Other smaller studies in the US are more or less in agreement with the Swedish data.

Was the Study Perfect?

By no means.  It’s pretty much impossible to do a perfect study.  There are too many variables to observe with fidelity, plus loads of unknown variables affecting outcome not yet figured out. Still,  following 3.4 million people with registered outcome over 12 years will be a very hard act to follow.

Why Did People Live Longer?

There are numerous studies showing the  short term physiologic effects of dog ownership.  People with dogs show less prominent stress responses.  They demonstrate less elevated states of their sympathetic nervous systems.

Yet the biggest impact impact seems to come from several factors: 1. Dog owners walk more.  This was particularly true of singletons.  There’s nobody else around to walk the dog.  Even in harsh weather (and Sweden has plenty of it) you have to walk the dog.

Next, came the benefits of social engagement between species.  Dog owners report a particular kind of happiness living with their animals (so do cat lovers, by the way.)

Third, people with dogs meet other dogs – and their owners.  Social support is a very large factor in cardiovascular risk, which accounted for an estimated 45% of total mortality in Europe in 2016.   People with dogs can develop attachments to their animal, other animals, and other humans.   Increased social engagement may be a big factor in why singletons benefitted more from dog ownership than others.

Bottom Line

Much can be learned from the Swedish dog ownership study.  Some implications are:

1. National health registries can provide a lot of useful data that can guide policy and treatment.

To get good results you need good data.  The Swedish dog ownership study not only had excellent human data, particularly on socioeconomic variables, it also had terrific animal data.  Most cohort studies, generally used as “gold standards” in epidemiologic research, cannot enforce the same kind of followup results that national registry data can provide. 

Plus only about 13% of Swedes were dog owners.  The benefit to singletons and the elderly can help guide national public health policy. 

2. There is little evidence that owning dogs has directly deleterious effects on human populations.  Worries about dogs’ overall effects on environmental resources must be contrasted with effects on health and mortality.

3. Social support matters a lot to survival.  Much of this social support can occur cross-species.

In America today, perhaps 25% of people claim to have no clear, trustable friend.  Despite the pervasiveness of social media, or as others would claim, because of it, people now declare they feel more lonely and alone than before.

Loneliness is a major cause of mortality.  It might be time to cue the aid of humanity’s best friend.


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