A case-control study of the risk factors for canine juvenile-onset generalized demodicosis in the USA

Canine juvenile-onset generalized demodicosis (JOGD) is a common skin disorder suspected to be associated with multiple risk factors, including breed predispositions. These risk factors have not been well documented in a large population. A retrospective case-control study was conducted by searching the electronic medical records of 1,189,906 dogs examined at 600 hospitals during 2006 in order to assess the risk factors associated with JOGD in the USA. Multivariate analyses were conducted using logistic regression to estimate the relative risk with the odds ratio for variables hypothesized to influence the risk for canine demodicosis. Breeds (odds ratio) found to have the greatest association with a diagnosis of JOGD were American Staffordshire terrier (35.6), Staffordshire bull terrier (17.1) and Chinese shar-pei (7.2). Nonbreed risk factors (odds ratio) significantly associated with a diagnosis of JOGD were the diagnosis of pyoderma (5.5), coccidiosis (2.7) or hookworms (1.5), short coat (1.9) and nonenrollment in a preventative care wellness plan (1.5). Documenting these risk factors may help veterinarians to prioritize differential diagnoses and will aid in the design of prospective studies to elucidate the pathogenesis of demodicosis in dogs.