It’s said that dogs resemble their owners, but the similarities may also extend to their risk of diabetes, research suggests. The same cannot be said of cat owners and their companions, however. Previous studies had hinted that overweight owners tend to have porkier pets, possibly because of shared health behaviours such as overeating or not taking regular exercise. To investigate whether this extended to a shared risk of type 2 diabetes, Beatrice Kennedy, of Uppsala University in Sweden, and colleagues turned to insurance data from Sweden’s largest pet insurance company, using owners’ 10-digit national identification numbers to pull their anonymised health records. Comparing data from 208,980 owner/dog and 123,566 owner/cat pairs, they discovered that owning a dog with diabetes was associated with a 38% increased risk of having type 2 diabetes compared with owning a healthy hound. Personal and socioeconomic circumstances of the dog owners could not explain this link. No shared risk of diabetes was found between cat owners and their pets, however. The research was published in the British Medical Journal. As in humans, diet and obesity can influence the risk of type 2 diabetes in both types of animals. Also like humans, the prevalence of diabetes in dogs and cats appears to be on the increase. “Given the previous research on the shared risk of [being overweight] between dog owners and their animals, we believe that shared dietary habits and also physical activity levels might be involved,” said Kennedy. The absence of a shared risk between cats and their owners may also point towards physical activity being an important factor. “Cats usually prefer more independence from their owners when it comes to their movements,” Kennedy said. Shared environmental exposures to things such as pollutants or chemicals between dogs and their owners could be another avenue worth exploring, she added. Because this was an observational study, the researchers could not confirm the underlying cause of the association. However, given that it exists, a diagnosis of diabetes in any household member – including canine companions – could signal a need to reassess the health behaviours of the whole family unit. “The diabetes of the dog could be a marker of something important going on,” Kennedy said. “We know that there are quite strong emotional bonds between dog owners and their dogs. Perhaps that bond extends to other health behaviours and risks.”