Assessment of Vitamin D in Rheumatoid Arthritis and Its Correlation with Disease Activity

BACKGROUND: Vitamin D is believed to have an immunomodulatory and anti-inflammatory action, and its deficiency has been linked with several autoimmune disorders, including rheumatoid arthritis (RA). The relationship between the severity of RA and serum levels of Vitamin D is a subject of immense interest and therapeutic implications. MATERIALS AND METHODS: This was a prospective, comparative study conducted on 100 participants, 50 cases of RA and 50 healthy controls, all in the age group of 18–75 years. Serum Vitamin D levels were measured and compared in cases and controls. Vitamin D levels in RA patients were also assessed in different stages of disease activity to assess the correlation between the two. RESULTS: Eighty-four percent patients of RA were Vitamin D deficient versus only 34% of controls. The serum Vitamin D levels were also significantly lower in the RA patients (mean value of 21.05 ± 10.02 ng/ml), as compared to the controls (mean value of 32.87 ± 14.16 ng/ml). There was a significant inverse correlation between serum Vitamin D levels and RA disease activity. The mean serum Vitamin D levels were 35.28 ± 9.0 ng/ml, 33.80 ± 4.1 ng/ml, 22.47 ± 6.18 ng/ml, and 14.21 ± 6.97 ng/ml in the remission, low disease activity, moderate disease activity, and high disease activity groups, respectively. CONCLUSIONS: Vitamin D deficiency is more common in RA patients and may be one of the causes leading to development or worsening of the disease.