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What Causes Diabetes in Dogs

By the Dog Health Handbook team · Updated · Fact-checked against current veterinary references (see sources)

Key takeaways

  • Most diabetes comes from permanent loss of insulin-producing cells.
  • Pancreatitis can destroy these cells over time.
  • Obesity, Cushing's, the heat cycle and steroids cause insulin resistance.
  • Higher-risk breeds include Australian Terriers, Samoyeds and Border Terriers.
  • Healthy weight and spaying lower the known risks.

Table of Contents

Research Cell loss Insulin resistance Breeds Age and sex Food Prevention FAQ Sources

Diabetes and Blood Sugar Quicklinks

Diabetes Causes Signs Treatment Diet Ketoacidosis (DKA) Low Blood Sugar Life Expectancy Diabetes Insipidus

Diabetes in dogs is caused mainly by permanent loss of the beta cells in the pancreas that make insulin. That loss comes from immune damage, cell degeneration or repeated bouts of pancreatitis.1,2,3 Other conditions cause insulin resistance, meaning the body stops responding properly to insulin. These include obesity, Cushing's disease, the heat cycle (diestrus) and pregnancy in unspayed females, infections, dental disease, hypothyroidism and steroid or progestin medicines. On their own these usually don't cause diabetes, but they can push a dog with failing beta cells into it.1,4 Genetics matter too: some breeds, such as Australian Terriers, Samoyeds, Border Terriers and West Highland White Terriers, are at higher risk.1,5,6,7 Most dogs are diagnosed in middle age or later, usually after age 8.1,5

Talk to your vet if your dog:

  • Is drinking and urinating more after a recent course of steroids8,9
  • Is an unspayed female drinking more 1 to 2 months after a heat cycle. This can be diestrus diabetes or a uterine infection (pyometra).9
  • Has had pancreatitis and now drinks more or loses weight1,3

What the Research Says

  • Steroids raise the risk. A 2023 UK study of 565 diabetic dogs found that steroid treatment in the 6 weeks before diagnosis was linked to about 4 times higher odds of diabetes.8
  • Obesity and sex. In the UK VetCompass study, obese dogs had about 2.7 times the odds of diabetes, and unspayed females about 3 times.5
  • Immune genes. A 2020 genetic study found immune-system gene types linked to higher risk in Cocker Spaniels and Labradors, and protective types in others.7
  • Females in Sweden. In 180,000 insured Swedish dogs, 72% of diabetic dogs were female, and in some breeds such as Swedish Elkhounds almost all were.6

Loss of Insulin-Producing Cells

AAHA describes the main problem in dogs as "an absolute insulin deficiency from permanent beta cell loss."1 The causes include:

  • Immune-mediated destruction of the beta cells1,3
  • Vacuolar degeneration, where the cells break down1
  • Repeated or severe pancreatitis, which damages the pancreas over time. See pancreatitis in dogs.1,2

Experts now consider the cause "complex and multifactorial," with genetic susceptibility likely.1,10

Insulin Resistance

  • Obesity1,5
  • Cushing's disease (too much cortisol). See Cushing's disease in dogs.2,4
  • The heat cycle and pregnancy in unspayed females. Progesterone causes the mammary glands to release growth hormone, which blocks insulin.2,11
  • Medicines: steroids and progestins, including steroid creams, eye drops and ear drops4,8
  • Infections and dental disease4,12
  • Hypothyroidism and high blood fats1

Breeds at Risk

Breed risk varies by country and study.5,6,2

  • AAHA 2026: Australian Terriers, Beagles, Samoyeds and Keeshonds1
  • UK primary care: higher odds in Border Terriers and West Highland White Terriers; lower odds in German Shepherds, Shih Tzus and Staffordshire Bull Terriers5
  • Sweden: highest in Australian Terriers, Samoyeds, Swedish Elkhounds and Swedish Lapphunds6
  • Merck Veterinary Manual: small breeds such as Yorkshire Terriers, Cavalier King Charles Spaniels and Bichon Frises; also Miniature Poodles, Dachshunds, Schnauzers and Cairn Terriers2,13

Any breed, including mixed breeds, can develop diabetes.2,13

Age and Sex

Diabetes is "most commonly a disease of middle-aged to older dogs."1 In Sweden the average age at first insurance claim was 8.6 years.6 Females are affected more often, and unspayed females are at the highest risk.13,5

Can Food Cause Diabetes?

No study shows that table food directly causes diabetes in dogs. However, obesity raises the risk, and PetMD lists high-fat diets among risk factors, and repeated pancreatitis can destroy insulin-producing cells over time.5,1,14

Can Diabetes Be Prevented?

There's no proven way to prevent diabetes, but you can lower the known risks:5,8,4

  • Keep your dog at a healthy weight.5,15
  • Talk to your vet about spaying females that aren't intended for breeding.5,4
  • Use steroid medicines only when needed, especially in at-risk breeds.8

Frequently Asked Questions

Why did my dog suddenly get diabetes?

Beta cells are usually lost gradually. Signs often appear only once most are gone or a trigger such as pancreatitis, infection or the heat cycle adds insulin resistance.

What dog breeds are most likely to get diabetes?

Australian Terriers, Samoyeds, Border Terriers and West Highland White Terriers are among the higher-risk breeds.

At what age do dogs get diabetes?

Usually in middle age or later, most often after 8 years.

Can steroids cause diabetes in dogs?

Steroids cause insulin resistance and are linked to higher odds of diabetes, especially in at-risk dogs.

Is diabetes in dogs genetic?

Partly. Breed risk and immune genes play a role.

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Sources and further reading

This article was rewritten and fact-checked on October 23, 2026 against current veterinary references and specialist guidelines:

  1. AAHA Diabetes Management Guidelines for Dogs Task Force. Section 1: Overview of Diabetes Mellitus in Dogs. 2026 AAHA Diabetes Management Guidelines for Dogs, 2026.
  2. Buishand F. Diabetes Mellitus in Dogs and Cats. Merck Veterinary Manual, updated May 2026.
  3. University of Missouri Veterinary Health Center. Diabetes. University of Missouri Small Animal Internal Medicine.
  4. AAHA Diabetes Management Guidelines for Dogs Task Force. Section 7: Troubleshooting in Diabetic Dogs. 2026 AAHA Diabetes Management Guidelines for Dogs, 2026.
  5. Heeley AM, O'Neill DG, Davison LJ, Church DB, Corless EK, Brodbelt DC. Diabetes mellitus in dogs attending UK primary-care practices: frequency, risk factors and survival. Canine Medicine and Genetics, 2020.
  6. Fall T, Hamlin HH, Hedhammar A, Kampe O, Egenvall A. Diabetes mellitus in a population of 180,000 insured dogs: incidence, survival, and breed distribution. Journal of Veterinary Internal Medicine, 2007.
  7. Denyer AL, Massey JP, Davison LJ, Ollier WER, Catchpole B, Kennedy LJ. Dog leucocyte antigen (DLA) class II haplotypes and risk of canine diabetes mellitus in specific dog breeds. Canine Medicine and Genetics, 2020.
  8. Davison L, O'Neill D, Brodbelt D, Church D, Heeley A. Assessment of glucocorticoid and antibiotic exposure as risk factors for diabetes mellitus in selected dog breeds attending UK primary-care clinics. Veterinary Record, 2023.
  9. AAHA Diabetes Management Guidelines for Dogs Task Force. Section 2: Recognizing and Diagnosing DM in Dogs. 2026 AAHA Diabetes Management Guidelines for Dogs, 2026.
  10. Corradini S, Fracassi F. Canine diabetes mellitus. Veterinary Focus (IVIS), 2017.
  11. Behrend E, Holford A, Lathan P, Rucinsky R, Schulman R. 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. Journal of the American Animal Hospital Association, 2018.
  12. Silvestrini P. Insulin Resistance in Practice: Diagnosis and Management. SEVC Annual Conference, Barcelona (IVIS), 2014.
  13. Bruyette D. Disorders of the Pancreas in Dogs. Merck Veterinary Manual (Dog Owners), updated May 2026.
  14. Jones L. Diabetes in Dogs: Causes, Signs, and Treatment. PetMD, updated November 2025.
  15. American Veterinary Medical Association. Diabetic Pets. AVMA owner brochure, revised 2010.

About this article

Last updated : fully rewritten using the 2026 AAHA Diabetes Management Guidelines for Dogs, the Merck Veterinary Manual, UK VetCompass studies and genetic research, plus International Veterinary Information Service (IVIS) proceedings and research published 2022 to 2026.

This page is for general information and is not a substitute for an exam by your veterinarian.