Abstract
INTRODUCTION: Periodontal disease is one of the most common oral disorders in companion animals. However, quantitative evidence regarding whether the rate of age-related increases in risk differs among individual breeds, breed groups, or body size categories remains limited. This study aimed to characterize age-associated patterns and breed-group-level variations in periodontal disease among dogs and cats using nationwide insurance claims data from Japan. METHODS: The analyses primarily used anonymized claims records from animals whose insurance policies began in 2023. After excluding breeds with fewer than 100 individuals, the dataset comprised 688,665 dogs representing 81 breeds and 185,782 cats representing 38 breeds. Generalized linear mixed models with a binomial distribution and logit links were applied. RESULTS: For both species, the claims rate increased with age, and the rate of increase in cats was approximately 3.5% lower than that of dogs. In dogs, body size showed a strong association with the predicted probability of a periodontal disease claim at less than 1 year of age (baseline risk); however, the slopes of the age effect were similar across size categories. At the breed-group level, four epidemiological patterns were identified based on the combination of baseline risk and the magnitude of the age effect: (1) high baseline risk with a gentle slope, (2) low baseline risk with a steep slope, (3) moderately high baseline risk with a steep slope, and (4) both baseline risk and slope near the overall mean. CONCLUSION: No significant correlation was observed between baseline risk and age, suggesting that the initiation and progression of periodontal disease in dogs is governed by partially distinct determinants. In cats, the baseline risk showed minimal variation among breeds, whereas the effect of age differed. Brachycephalic breeds, including Exotic, Himalayan, and Persian cats, exhibit steep age-related increases in risk. These findings provide a comprehensive overview of age- and breed-related patterns of periodontal disease risk in dogs and cats using real-world data and highlight the importance of preventive dental care tailored to age and breed.