Meat consumption and risk of primary hip and knee joint replacement due to osteoarthritis: a prospective cohort study

Wang Y, Simpson JA, Wluka AE, English DR, Giles GG, Graves S, Cicuttini FM · BMC Musculoskeletal Disorders

A registry-linked hard endpoint — the operation, not a questionnaire — and the result runs against expectation. Fresh red meat showed a dose-response *inverse* association with hip replacement (HR 0.94 per extra serving/week, 95% CI 0.89-0.98) and no association with knee replacement (HR 0.98, 95% CI 0.94-1.02). Processed meat, chicken and fish were associated with neither. The authors suggest an effect on bone strength and hip shape rather than on cartilage.

Population

Melbourne Collaborative Cohort Study participants recruited 1990-1994, linked to the Australian National Joint Replacement Registry for 2001-2005

Intervention

Higher intake of fresh red meat, processed meat, chicken or fish by food-frequency questionnaire

Comparator

Lower intake

Limitations

Joint replacement is a decision as much as a disease state, and access to surgery tracks with income and health-seeking behaviour. Diet measured once, 7-15 years before the outcome window. The hip-only finding with a null at the knee is the pattern most likely to be confounding rather than biology.