Effect of Vitamin D supplementation on synovial tissue volume and subchondral bone marrow lesion volume in symptomatic knee osteoarthritis

Background Data from a recent clinical trial of vitamin D therapy in knee OA suggests that, compared to placebo, vitamin D therapy may be associated with a reduction in effusion-synovitis. Our aim was, using contrast-enhanced (CE) magnetic resonance imaging (MRI), to examine the effect of vitamin D therapy on synovial tissue volume (STV) and also subchondral bone marrow lesion (BML) volume in men and women with symptomatic knee OA. Methods Data was acquired from participants who took part in a randomised placebo-controlled trial (UK VIDEO) investigating the effect of vitamin D therapy (800 IU cholecalciferol daily) on radiographic joint space narrowing. A subsample had serial CE MRI scans acquired during the trial. Subjects with serial images were assessed (N = 50) for STV and subchondral BML volume. The difference in the mean change from baseline in these structural outcomes between intervention and placebo groups was assessed using random-effects modelling. Results The mean age of the 50 subjects (24 active group, 26 placebo group) who contributed data to the analysis was 63.3 years (SD 6.5) and 74% were female. There was no significant difference at 2 years follow-up between the vitamin D and placebo groups in the mean change from baseline for STV (93.9 mm3, 95% CI -1605.0 to 1792.7) and subchondral BML volume (− 313.5 mm3, 95% CI -4244.7 to 3617.7). Conclusions Vitamin D supplementation does not appear to have an effect on synovitis or BML volume in patients with symptomatic knee OA. Trial registration VIDEO was registered with EudraCT: ref. 2004-000169-37. The protocol for the trial can be accessed at https://www.ctu.mrc.ac.uk/studies/all-studies/v/video