The association between vitamin K status and knee osteoarthritis features in older adults: the Health, Aging and Body Composition Study

Shea MK, Kritchevsky SB, Hsu FC, et al. · Osteoarthritis and Cartilage

Very low plasma vitamin K — below 0.2 nM, the assay's limit of detection — was associated with greater progression of MRI cartilage damage (OR 1.7) and meniscus damage (OR 2.6) over 3 years. Only that lowest category moved anything: across the whole cohort plasma vitamin K was not associated with the presence of any knee feature at baseline.

Population

Community-dwelling older adults aged 70-79 (Health ABC); 791 had a usable baseline MRI and 523 of those a 3-year follow-up MRI, which is the sample the progression figures come from

Intervention

Plasma phylloquinone and dephosphorylated-uncarboxylated MGP measured; no intervention

Comparator

Plasma phylloquinone >=1.0 nM, the concentration usually reached when intake meets the recommendation

Limitations

Observational; ORs have wide intervals, and the exposed group is 68 people. The paper sets its own thresholds because no sufficient concentration is defined for vitamin K. The uncarboxylated-MGP associations seen at baseline did not reappear over three years. K1 as status marker; no K2 exposure data.