Vitamin K in hand osteoarthritis: results from a randomised clinical trial

Neogi T, Felson DT, Sarno R, Booth SL · Annals of the Rheumatic Diseases

Null primary result: no overall effect on radiographic hand OA. In the subgroup who were vitamin-K insufficient at baseline and reached sufficiency, there was ~47% less joint space narrowing (P=0.02) — hypothesis-generating only.

Population

Older adults enrolled in a 3-year phylloquinone supplementation trial (ancillary hand-OA study; 193 vitamin K, 185 placebo)

Intervention

Phylloquinone (vitamin K1) 500 micrograms daily in a multivitamin for 3 years; both arms also took calcium 600 mg and vitamin D 400 IU daily

Comparator

Identical multivitamin without phylloquinone

Limitations

Ancillary analysis of a trial designed for other outcomes; the positive finding is a post-hoc subgroup; K1 not K2; hand not knee. Both arms received vitamin D, which the authors note may have narrowed any difference.