Effects of vitamin D on disease activity and serum interleukin-6 in rheumatoid arthritis

AIM: Vitamin D3 or 25(OH)D3 may have a potential role in rheumatoid arthritis (RA) pathogenesis by inhibiting the expression of pro-inflammatory cytokines including interleukin-6 (IL-6). The aim of this study is to determine the clinical factors of vitamin D deficiency in multi-ethnic Malaysian RA patients and its association with disease activity, functional disability and serum IL-6 levels.

METHOD: One hundred RA patients and 50 healthy controls, sex- and age-matched, were recruited. Disease Activity Score of 28 joints and Health Assessment Questionnaire scores were assessed. Baseline serum 25(OH)D3 and IL-6 were measured in all subjects. RA patients who were vitamin D deficient were given loading doses of vitamin D3 and repeated assessments were done.

RESULTS: Vitamin D deficiency (<50 nmol/L) was found in 63% of RA patients and 76% of healthy controls. Chinese RA patients and healthy controls had significantly more sufficient 25(OH)D3 levels compared to Malays and Indians (P