New research suggests that if a dog has diabetes, there is an increased risk that its owner will, too.

Person petting a dogShare on Pinterest
Catherine Falls Commercial/Getty Images.

The special bond between dogs and their owners may, at times, be a bit too special, according to a new study from researchers in Sweden and the United Kingdom.

According to this research, the owners of dogs with diabetes are more likely to acquire type 2 diabetes themselves.

However, the investigators found no such association between cats and their owners.

The link is not a total surprise, as previous research has found that people with overweight who own dogs tend to have overweight canines as well, perhaps due to a shared sedentary lifestyle. Having overweight increases a person’s risk of developing type 2 diabetes.

Diabetes — which the World Health Organization (WHO) say affected 422 million people worldwide in 2014 — is on the rise.

The WHO note that from 1980 to 2014, the prevalence of diabetes among adults rose from 4.7% to 8.5%, while from 2000 to 2016, there was a 5% increase in early deaths from the disease. Experts expect diabetes to become even more prevalent as the global population ages and as less active lifestyles and obesity become more common.

The study appears in the BMJ as part of their Christmas 2020 issue.

Using Swedish veterinary records from the start of 2004 to the end of 2006, the researchers identified 208,980 owner-dog pairs and 123,566 owner-cat pairs.

Tracking the health of these owner-pet pairs from January 1, 2007, to December 31, 2012, the researchers identified owners with type 2 diabetes from the Swedish National Patient Register, the Cause of Death Register, and the Swedish Prescribed Drug Register. To identify the dogs with diabetes, the researchers analyzed veterinary insurance records.

The researchers controlled for various possible confounding factors, including each owner’s natal sex, age, marital status, area of residence, income, and education level, as well as each dog’s breed, sex, and age.

Among humans — regardless of their pets’ health — there were 7.7 cases of diabetes per 1,000 human years for dog owners, and slightly more for cat owners at 7.9 cases. Looking at the pets alone, there were 1.3 cases of diabetes per 1,000 dog years and 2.2 cases of diabetes for every 1,000 cat years.

Putting the health of the owners and their pets together, however, revealed the striking correspondence between the results.

People who owned a dog with diabetes had a 38% greater likelihood of developing type 2 diabetes than those who owned a dog without diabetes.

Looking at the link from the opposite direction, an association was also apparent:

The researchers also found that dogs with owners who had type 2 diabetes were 28% more likely to develop diabetes. However, once the team factored in human age, the result was no longer statistically significant.

There was no such association between humans and their cats.

The researchers caution that there are a couple of limitations to their study. First, it is restricted to dog and cat owners who have the financial wherewithal to purchase veterinary insurance. Second, as an observational study, it does not delve into why this association occurs.

However, the authors suggest, the fact that the diabetes connection occurs between owners and dogs but not owners and cats may provide a clue as to what is going on. Dogs and their owners tend to engage in the same level of physical activity more often than humans and their felines.

While people are being physically active, particularly outdoors, dogs often accompany them and, therefore, also benefit from the exercise.

The opposite is also true — when humans are sedentary, their dogs are more likely to be physically inactive, as well.

The activity level of cats, on the other hand, has more to do with their own agenda than their owner’s. Even if an owner does not engage in regular exercise, their cat is likely to do an ample amount of physical activity.

Unfortunately, the study did not include any data on health behaviors, such as diet or physical activity, to test this theory. Nevertheless, the authors of the study suggest that their research can “serve as a sentinel for shared diabetogenic health behaviors and environmental exposures.”

The study’s findings suggest that if a dog receives a diagnosis of diabetes, it may make sense for its owner to undertake an assessment of their own lifestyle to reduce their risk of developing type 2 diabetes.