Epidemiology of mammary tumours in bitches under veterinary care in the UK in 2016.

BACKGROUND: There is limited information on the epidemiology of canine mammary tumours. This study aimed to estimate the incidence and risk factors for mammary tumours in UK bitches. METHODS: A nested case-control study was conducted within VetCompass to estimate the frequency and risk factors for clinically diagnosed mammary tumours during 2016 (VetCompass study). A second case-control study explored further breed associations for cases confirmed histopathologically compared to the VetCompass controls (laboratory study). Multivariable logistic regression was used to evaluate associations between risk factors and mammary tumours. RESULTS: The incidence of mammary tumours was 1340.7/100,000 per year (95% confidence interval: 1198.1-1483.3). A total of 222 clinical cases (VetCompass study) and 915 laboratory cases (laboratory study) were compared to 1515 VetCompass controls in the two analyses. In the VetCompass study, Springer and Cocker Spaniels, Boxers, Staffordshire Bull Terriers and Lhasa Apsos had increased odds of developing mammary tumours. Neutering was associated with reduced odds, while odds increased with increasing age and a history of pseudopregnancy. In the laboratory study, increasing age was associated with greater odds of mammary tumours, and the breeds most at risk were similar to those identified in the VetCompass study. LIMITATIONS: The timing of neutering was not consistently available. Comparing laboratory cases to VetCompass controls provided only exploratory evidence for the breed associations identified. CONCLUSIONS: The study provides an update on the frequency of canine mammary tumours.

Prevalence and correlates of hepatitis C virus-associated inflammatory arthritis in a population-based cohort.

OBJECTIVES: The objectives of this study were to determine the prevalence of hepatitis C virus-associated inflammatory arthritis, to describe its clinical and immunologic correlates, and to identify features that are characteristic of arthritis in chronic hepatitis C. METHODS: Participants with chronic hepatitis C infection enrolled in a population-based cohort study in Alaska and who had not received anti-viral treatment for hepatitis C were recruited. In a cross-sectional study, we assessed joint symptoms and signs, performed autoantibody and cytokine testing, and abstracted medical records for features of hepatitis C and arthritis. RESULTS: Of the 117 enrolled participants, 8 (6.8%) had hepatitis C-associated arthritis. The participants with arthritis were younger than those without (median age: 45 vs. 52, p = 0.02). Rheumatoid factor was commonly present among patients with hepatitis C-associated arthritis. The only studied autoantibody found more commonly in patients with HCV arthritis than those without arthritis was anti-nuclear antibody (63% vs. 23%, p = 0.026). The only joint symptom significantly more common in hepatitis C arthritis was self-reported joint swelling (75% vs. 26%, p = 0.007). Features of fibromyalgia were more common and functional status was worse in those with arthritis than those without. No cytokines differed in patients with and without arthritis. There were no associations of arthritis or autoantibodies with liver-related outcomes. CONCLUSIONS: In this study of a cohort of individuals with chronic HCV infection, HCV-associated arthritis was present in less than 10%. Few serologic features distinguished participants with or without arthritis, but self-reported joint swelling was more common in those with arthritis.