Diabetes mellitus (DM) is a common endocrinopathy in dogs, mainly middle-aged to older dogs. This study, conducted in Sweden, evaluated a population of 182,087 dogs that were 5 to 12 years of age. A large proportion of the Swedish dog population is insured, and these data were collected on dogs insured by the Agria Insurance Company. Most dogs in Sweden are not neutered, but the sexual status of all dogs in the study was not known. There were 860 insurance claims for DM, and the mean age for the first claim was 8.6 years. Females represented 618 (72%) of the DM patients. The median survival time after the first DM claim was 57 days but increased to 2 years if the 223 dogs that died within 1 day after diagnosis were excluded. It was not known whether the high death rate on the date of DM claim was due to elective euthanasia or diabetic complications, such as ketoacidosis. Australian terriers, Samoyeds, Swedish elkhounds, and Swedish lapphunds were found to have the highest incidence of DM. In some breeds, such as Swedish elkhounds, beagles, Norwegian elkhounds, and border collies, the disease occurred almost exclusively in females. Risk factors for DM identified in the multivariable model were breed, previous hyperadrenocorticism, and being female.

COMMENTARY: This study confirms earlier epidemiologic studies regarding the variability of incidence of DM among  breeds. Of interest is the fact that 72% of patients were female. Although neuter status was not known, since most dogs in Sweden are not altered, it could be speculated that most of the dogs were intact. A seasonal variation was noted in this study, with an increase in diagnosis occurring in spring (April-June). This may reflect onset of progesterone-induced DM triggered by increased estrous activity in intact females. Although this study confirms breed disposition, breeds found to be predisposed to DM in this study differed from those of a U.S. study,1  which found miniature schnauzers, miniature poodles, pugs, and toy poodles at high risk for DM (in addition to Samoyeds). More studies are warranted on the molecular genetics of DM in dogs.

1. Breed distribution of dogs with diabetes mellitus admitted to a tertiary care facility. Hess RS, Kass PH, Ward CR. JAVMA 216:1414-1417, 2000.

Diabetes mellitus in a population of 180,000 insured dogs: Incidence, survival, and breed distribution. Fall T, Hamlin HH, Hedhammar A, et al. J VET INTERN MED 21:1209-1216, 2007.