Associations Between Vitamins C and D Intake and Cartilage Composition and Knee Joint Morphology Over 4 Years: Data From the Osteoarthritis Initiative

Joseph GB, McCulloch CE, Nevitt MC, Neumann J, Lynch JA, Lane NE, Link TM · Arthritis Care & Research

The imaging follow-up to Framingham, and it is more sober. Higher vitamin C intake was associated with lower cartilage T2 — the MRI measure of matrix quality — averaged and at the medial tibia, and with lower medial tibial WORMS scores. The standardized coefficients are -0.07 to -0.05, which is a real association and a very small one. Vitamin D, measured in the same subjects, produced coefficients three to five times larger and was the only vitamin whose consistent supplement use predicted less worsening over four years.

Population

Osteoarthritis Initiative participants with Kellgren-Lawrence grades 0-3, followed 4 years

Intervention

Baseline vitamin C and vitamin D intake from diet and supplements by food frequency questionnaire

Comparator

Lower intake, within cohort

Limitations

Observational, and the vitamin C findings are cross-sectional associations with baseline imaging rather than the longitudinal protection the vitamin D arm showed. Effect sizes are near the floor of detectability in a cohort of 1,785. Diet questionnaires misclassify intake. The paper's own conclusion asks for randomized trials of vitamin D and does not make that call for vitamin C.