11. Undifferentiated arthritis

was associated with a higher disease activity and an increase in serum vitamin D was associated with reduced disease activity over time [50]. Improving vitamin D status may improve other common manifestations as well, such as fatigue [51] and cognitive

The role of hypovitaminosis D in the pathogenesis of rheumatoid arthritis has

High rates of vitamin D deficiency have been observed in patients with rheumatic diseases. A study demonstrated that in patients with RA, VDD was seen in 64% and insufficiency in 28%. Similarly, in spondyloarthritis (SpA) patients 48% had VDD and 35% had insufficiency [55]. The prevalence of VDD is quite in RA patients. The COMEDRA study showed that 55.8% of RA patients had vitamin D insufficiency and 3.6% had deficiency [56]. Eighty-four percent of RA patients were VDD in a recently published study by Meena. It also showed a significant inverse correlation between serum vitamin D levels and RA disease activity [57]. A metaanalysis by Lee and Bae supported this result suggesting that the vitamin D level is associated with susceptibility to RA and RA activity [58]. Similarly, a negative association between serum vitamin D and RA disease activity was demonstrated in few studies [59–62]. Levels of 25(OH)D3 were also found to be negatively correlated to CRP and ESR [62]. However, relationship between 25(OH)D and levels of rheumatoid factor or anti-cyclic citrullinated peptide antibodies has not been

The COMORA study showed that vitamin D was insufficient in 54.6% and deficient in 8.5% of the RA patients. Low levels of vitamin D were associated with disease activity of RA and corticosteroid dosage and comorbidities like lung disease

In comparison to healthy adults, VDD is more prevalent in people with autoimmune diseases including connective tissue diseases (CTDs) [65]. It may also have a pivotal role in progression of undifferentiated CTDs to well-defined and more severe disease [65]. There are few evidences which showed the antifibrotic property of vitamin D [66]. Low vitamin D levels are also associated with more severe disease, low diffusing capacity for carbon monoxide (DLCO), and advanced-stage nailfold capillaroscopy changes in patients with scleroderma [67, 68]. However, a recent meta-analysis revealed that though VDD is quite common in scleroderma

Over the years, it has been proven that vitamin D is necessary for optimum muscle and bone health. In CTDs, vitamin D levels correlate with intensity of muscle weakness [68, 70]. It may also be considered as one of the risk factors in developing myositis [71]. However, the role of vitamin D in myositis or other CTDs has not been established yet. Studies have shown that in fibromyalgia, VDD is correlated with pain and disease activity [72] and correction of deficiency improves

patients, it does not correlate to the disease activity [69].

been the topic of interest in the recent past. Lower vitamin D levels possess increased risk for RA [53]. 1,25(OH)2D3 contributes to the regulation of matrix metalloproteinase and prostaglandin E2 production by synovial fibroblasts and

dysfunction [52].

Fads and Facts about Vitamin D

established yet [63].

the symptoms [73].

88

10. CTD

and osteoporosis therapy [64].

articular chondrocytes in RA [54].

9. RA

Significant association has been reported between vitamin D deficiency and nonspecific musculoskeletal pain, arthralgias, or undifferentiated arthritis [74, 75]. A positive correlation of VDD with undifferentiated arthritis [76] and early inflammatory arthritis [77] has been observed. It has also shown VDD as one of the risk factors of disease progression to RA [76, 78].
