A longitudinal study of the influence of lifetime food restriction on development of osteoarthritis in the canine elbow.

Objective— To report the effects of age and lifetime calorie restriction on development and progression of osteoarthritis (OA) in elbow joints of Labrador retrievers. Study Design— Longitudinal cohort study. Animals— Labrador retriever dogs (n=48). Methods— Puppies from 7 litters were allotted to 2 groups of 24 dogs each. Diet-restricted (DR) dogs received 25% fewer calories than control-fed (CF) pair mates. Elbow radiographs were taken at 6 and 8 years of age and end of life (EOL). Gross and histopathologic evaluations for OA occurred at EOL. Results— There was no statistical difference in radiographic OA frequency between groups at any of the time points. Radiographic OA severity was greater for CF dogs at 6 years only (P .05). Fragmented medial coronoid process, un-united anconeal process, and osteochondrosis were not present in any elbow. Conclusion— No differences in prevalence or severity of radiographic and histopathologic elbow OA were found between feeding groups. Diet restriction resulted in a 1.8-year extension in median lifespan but no additional incremental worsening of elbow disease. Evaluation at time points <6 years may have revealed larger differences in OA prevalence and severity between the dietary groups. Clinical Relevance— These findings support calorie restriction as a clinical tool to slow progression of elbow OA.