To assess vitamin D levels in rheumatoid arthritis (RA) patients and to find their relation to clinical parameters, fibromyalgia syndrome (FMS), quality of life (QoL) and disease activity.
The study included 63 RA patients and 62 controls. Clinical examination and laboratory investigations were performed. For patients, the Disease Activity Score (DAS-28), QoL index, Health Assessment Questionnaire II (HAQ II) and Modified Larsen score were calculated. 25-OH-vitamin D was measured in patients and controls.
The patients' mean age was 41.59 ± 9.69 years and disease duration 5.89 ± 3.67 years. The level of vitamin D in RA patients was significantly lower (23.11 ± 12.71 ng/mL) than that in the controls (32.59 ± 13.06 ng/mL) (P = 0.005) being deficient in 50.8%, insufficient in 23.8% and normal in 25.4%. The RA patients with FMS (n = 33) had significantly lower levels of vitamin D (19.08 ± 10.59 ng/mL) than those without (27.55 ± 13.51 ng/mL) (P = 0.008). The difference was significant on comparing those receiving hydroxychloroquine (17.39 ± 7.84 ng/mL) to those not (31.85 ± 13.85 ng/mL) (P < 0.001). Vitamin D significantly correlated with QoL index (r = 0.58, P < 0.001) and negatively with HAQ II (r = -0.36, P = 0.004) and BMI (r = -0.39, P = 0.001).
Special attention is required regarding vitamin D levels in RA patients with FMS and decreased QoL. Vitamin D should be corrected and supplementation considered among the RA management armamentarium.