SAN DIEGO, CA—Vitamin D deficiency contributed to the presence of rheumatoid arthritis (RA) in patients with early inflammatory arthritis (EIA), researchers presented at the 2013 ACR/ARHP Annual Meeting.
Seung-Geun Lee, Department of Internal Medicine, Pusan National University Hospital, South Korea, and study authors investigated the status of vitamin D in patients with EIA (>1 swollen joint, symptom duration of <6 months, not explained by another disease) compared with healthy controls. A total of 101 patients with EIA and 101 healthy controls were included at a rheumatology center in South Korea from March 2012–February 2013. Patients with EIA had a mean baseline serum (OH) vitamin D level of 14.2ng/mL (range 5.5–67.9) and the healthy control group had a mean baseline serum (OH) vitamin D level of 16.3 (range 4.6–23.3).
Serum 25(OH) vitamin D levels were assessed by radioimmunoassay. EIA patients were subdivided into RA (n=38) and non-RA (n=63) as defined by the 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) criteria.
Study results showed there was no significant difference observed in serum 25(OH) vitamin D levels between EIA and control cohorts (median 14.2 vs. 16.3, P=0.229). In subgroup analyses, patients with RA had significantly higher swollen joint count (SJC), tender joint count, erythrocyte sedimentation rate, C-reactive protein, rheumatoid factor, anti-citrullinated protein antibody (ACPA) and lower serum 25(OH) vitamin D levels than in non-RA patients.
Serum 25(OH) vitamin D levels in EIA patients were inversely correlated with the titer of ACPA (P=-0.214, P=0.031), SJC (P=-0.196, P=0.049) and patient’s visual analogue scale (P=-0.202, P=0.043), researchers concluded.
Overall, severe vitamin D deficiency (<10ng/mL) was significantly associated with the diagnosis of RA (OR=3.259, 95% CI 1.137–9.342; P=0.028). “The serum vitamin D levels in patients with EIA were similar but the deficiency contributed to the presence of RA in this patient group,” concluded Dr. Lee.