Do you both need to go walkies more?

Here’s some more fuel for “dog or cat” debate.

Researchers have found that people who own a dog with diabetes are more likely to develop Type 2 diabetes themselves – but there appears to be no such risk for cat owners.

Previous studies have suggested a link between adiposity (being severely overweight) in dogs and owners, likely linked to health behaviours such as activity level, but this is the first to investigate possible implications.

A Swedish and British team led by the University of Uppsala used veterinary care insurance data to identify 208,980 owner-dog pairs (175,214 owners and 132,783 dogs) and 123,566 owner-cat pairs (89,944 owners and 84,143 cats) from 1 January 2004 to 31 December 2006.

This information was linked to Swedish health and drug registers to identify cases of Type 2 diabetes in dog and cat owners and cases of diabetes in their pets over a six-year follow-up period (1 January 2007 to 31 December 2012).

A range of potentially influential factors was taken into account, include the personal and socioeconomic circumstances of the owners – such as age, sex, region of residence, marital status, education level and income – and the age, sex and breed of pet.

The rate of Type 2 diabetes during follow-up was 7.7 cases per 1000 person years at risk in dog owners and 7.9 cases per 1000 person years at risk in cat owners. The rate of diabetes in the pets was 1.3 cases per 1000 dog years at risk and 2.2 cases per 1000 cat years at risk.

Thus, the researchers say, owning a dog with diabetes was associated with a 38% increased risk of Type 2 diabetes compared with owning a dog without diabetes. This estimate did not change noticeably after adjusting for other risk factors.

It also worked the other way: the risk of developing diabetes was 28% higher in dogs with an owner who had it compared with dogs with an owner who did not. However, this estimate was reduced after adjusting for age of the owner.

“We have not had access to information about household lifestyle behaviours, but we think the association might be due to shared physical activity patterns and possibly also shared dietary habits as well as shared risk of adiposity,” says Uppsala’s Beatrice Kennedy, a senior author of the team’s paper in the medical journal The BMJ.

“If shared exercise habits are indeed a key factor, it might further help explain why we don’t see any shared diabetes risk in cat owners and their cats.”

This is an observational study, so can’t establish cause, and the results are limited to pet owners who had the financial means to take out veterinary insurance and who received drug treatment for their diabetes.

Nevertheless, the researchers say it was a robust study showing results that could not be explained by personal and socioeconomic circumstances of the dog owners.

It is possible, therefore, that dogs with diabetes “could serve as a sentinel for shared diabetogenic health behaviours and environmental exposures”, they conclude.