A comprehensive review published in Osteoporosis International by the International Osteoporosis Foundation (IOF) Osteoimmunology Working Group has found that, while vitamin D deficiency is common and clinically relevant in patients with inflammatory rheumatic diseases, current evidence does not support a direct disease-modifying role for vitamin D supplementation.
The review examined data from randomised controlled trials, observational studies, systematic reviews, and meta-analyses covering conditions including rheumatoid arthritis, systemic lupus erythematosus, psoriatic arthritis, spondyloarthritis, systemic sclerosis, and Sjögren’s disease. Between 40% and 80% of patients with these conditions have insufficient vitamin D levels, with deficiency associated with higher disease activity, fatigue, pain, and poorer musculoskeletal outcomes.
Supplementation consistently corrected deficiency safely and showed modest benefits in disease activity in some patients, particularly those with low baseline vitamin D levels. However, evidence across studies was heterogeneous and inconsistent. Critically, large randomised trials and Mendelian randomisation studies did not confirm a causal relationship between vitamin D status and disease onset or sustained remission.
The authors recommend maintaining serum 25-hydroxyvitamin D concentrations of at least 30 ng/mL for skeletal and muscular health, in line with existing IOF guidance, but conclude that supplementation should not be considered a stand-alone disease-modifying intervention.
Several questions remain unresolved, including whether vitamin D deficiency directly contributes to disease mechanisms or primarily reflects chronic inflammation, the optimal serum thresholds for immune modulation, and the long-term safety of higher-dose supplementation strategies. The authors call for larger, well-designed randomised trials that stratify patients by baseline deficiency and genetic background to clarify causal mechanisms and long-term effects.
Source: Messina OD et al. Vitamin D in inflammatory rheumatic diseases: still a challenge. Osteoporosis International (2026). DOI: 10.1007/s00198-026-08066-7.
