Epidemiology of Diabetes Mellitus in Cats in England

Diabetes mellitus (DM) affects about 1 in 200 cats in England, according to a study recently published in the Journal of Veterinary Internal Medicine. Tonkinese, Norwegian forest, and Burmese cats had the highest odds of receiving a DM diagnosis. Increased body weight and age were associated with DM, but sex was not.

The study included records of 194,563 cats that visited 118 veterinary clinics in England between September 2009 and August 2014. Data were collected through the VetCompass initiative, which merges de-identified patient data from clinics’ computerized records into a single large dataset.

A total of 1128 cats (0.58%) met the inclusion criteria for DM. This result was slightly higher than previous estimates in cats in the United Kingdom (0.43%) and United States (0.42%) and slightly lower than a previous estimate in Australia (0.74%).

Burmese, Norwegian forest, and Tonkinese cats had the highest within-breed prevalences of DM. The odds of receiving a DM diagnosis were about 4 times higher in Tonkinese cats, 3.5 times higher in Norwegian forest cats, and 3 times higher in Burmese cats than in crossbred cats. Tonkinese and Burmese cats are genetically similar. Burmese cats in North America are genetically distinct and have not been found to have an increased risk of DM. The authors conclude that susceptibility to DM probably has a genetic component in cats.

Increased body weight and age were significant risk factors for DM. Compared with cats weighing less than 3.0 kg (6.6 lb), those that weighed 4.0 to 4.9 kg (8.8 to 10.8 lb) were more than 3 times as likely to have DM; those that weighed 5.0 to 5.9 kg (11.0 to 13.0 lb) were more than 5 times as likely. Compared with cats 3 to 5.9 years old, the odds of DM were over 5 times higher in cats 6 to 8.9 years old and 17 times higher in cats 9 to 11.9 years old.

Although male sex has previously been identified as a risk factor for DM, the results of this study showed no association between sex and DM after accounting for other variables. As a group, male cats in this study were significantly heavier than female cats, a finding that agrees with the results of other studies. According to the authors, some previous reports of increased risk for DM in male cats did not account for body weight as a confounding factor.

In this dataset, cats that were insured were twice as likely as uninsured cats to have a diagnosis of DM. Insured cats could be more likely to receive diagnostic workups, say the authors. It is also possible that participating clinics were more likely to record the insurance status for cats with diseases like DM.

The study results could have been affected by variations in diagnostics and electronic patient records among participating clinics, say the authors. Another limitation is that the private clinics participating in VetCompass might not accurately represent all veterinary clinics in England.

Dr. Laurie Anne Walden received her doctorate in veterinary medicine from North Carolina State University. After an internship in small animal medicine and surgery at Auburn University, she returned to North Carolina, where she has been in small animal primary care practice for over 20 years. Dr. Walden is also a board-certified editor in the life sciences and owner of Walden Medical Writing, LLC.