Vitamin D is well known for its role in building strong bones, shoring up immune defenses, and keeping the mind focused and sharp. It may also play a role in reducing the flare ups and symptoms of rheumatoid arthritis.

It’s estimated that about 1.3 million Americans have rheumatoid arthritis (RA). This autoimmune and inflammatory condition attacks joints, causing swelling, pain, and ultimately, irreversible damage if it is not treated.

Because it is an autoimmune condition, RA is difficult to treat: since the immune system is already mistaking joint tissue as something to be fought, dialing up an immune response can make symptoms even worse. The best option is to moderate the way the immune system reacts, without putting someone in danger of being prone to viruses or other diseases.

Vitamin D may be one nutrient that fits the bill. Although this study did not treat RA patients with vitamin D, it did find that lower vitamin D deficiency is a risk factor for RA activity and symptoms.

For anyone who spends most of their time indoors, or who lives in a region with little sunlight (or skin exposure to sunlight, which naturally synthesizes vitamin D in the body), adding vitamin D to a daily regimen is a good idea. The science of vitamin D has come a long way in the past few years, and even adding a supplement that supplies 5,000 IU of vitamin D daily is considered a reasonable (and reasonably-priced) way to get a consistent level of this valuable nutrient. The positive results may be well worth the small investment.

Abstract:

Lee YH, Bae SC. Vitamin D level in rheumatoid arthritis and its correlation with the disease activity: a meta-analysis. Clin Exp Rheumatol. 2016 Sep-Oct;34(5):827-833.

Objectives: This study aimed to evaluate the relationship between the 25-hydroxyvitamin D [25(OH)D] level and rheumatoid arthritis (RA) and the correlation between serum vitamin D level and RA activity.

Methods: We searched the PUBMED, EMBASE, and Cochrane databases and performed a meta-analysis examining the vitamin D level and prevalence of vitamin D deficiency in patients with RA compared to healthy controls and the correlation coefficients between the vitamin D level and disease activity score 28 (DAS28) in RA patients.

Results: Fifteen studies that included a total of 1,143 RA patients and 963 controls were available for this meta-analysis. The meta-analysis showed that the serum vitamin D level in the RA group was significantly lower than that in the control group (SMD=-0.608, 95% CI=-1.105-[-0.017], p=0.017). In addition, the prevalence of vitamin D deficiency was significantly higher in the RA group than in the control group (55.2% vs. 33.2%; OR = 2.460, 95% CI = 1.135-5.332, p=0.023). Thirteen studies evaluated the correlation between the vitamin D level and its activity in 924 RA patients. Meta-analysis showed a significant inverse correlation between the vitamin D level and DAS28 (Correlation coefficient =-0.278, 95% CI =-0.393-[-0.153], p=1.8 x 10-5).

Conclusions: Our meta-analysis demonstrates that serum vitamin D level is significantly low in patients with RA, vitamin D deficiency is prevalent in RA patients compared to controls, and the vitamin D level correlates inversely with RA activity. Our meta-analysis suggests that the vitamin D level is associated with susceptibility to RA and RA activity.