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). There was no significant difference between feeding groups for histopathologic prevalence or severity of OA. Similarly, there were no differences in gross OA lesions between the groups (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.