Immunological and humoral factors in rheumatoid arthritis: the association with bone mineral density

BACKGROUND: Different cytokines could affect bone tissue in patients with rheumatoid arthritis (RA). For formulation clinically significant conclusions about cytokines role in status of bone tissue in RA patients, actual studies are needed to obtain more data. AIM: To study the association of bone mineral density (BMD) with immunological and humoral factors in postmenopausal RA women. MATERIALS AND METHODS: The study included 73 postmenopausal women with RA (median age 63.0 56.0; 67.0 years). A clinical and laboratory examination was performed including dual-energy X-ray absorptiometry to assess BMD of the lumbar spine (L1–L4), femoral neck (FN) and total hip (TH), level measurement of C-reactive protein (CRP), rheumatoid factor (RF), antibodies to cyclic citrullinated peptide (ACCP), parathyroid hormone (PTH), myostatin, follistatin, interleukin 6 (IL-6), IL-6 receptors, insulin-like growth factor 1, adiponectin, leptin, fibroblast growth factor 23, tumor necrosis factor (TNF) SF12. RESULTS: Persons with osteoporosis (OP) have higher levels of adiponectin (p=0.002), TNF SF12 (p=0.015) and IL-6 receptors (p=0.014) compared to those without OP. L1–L4, FN and TH BMD positively correlated with leptin and IL-6; negative correlation was found between L1–L4 BMD and adiponectin, FN BMD and follistatin, TH BMD and TNF SF12 (p<0.05). Linear regression analysis revealed significant associations between L1–L4 BMD and PTH (β= -0.22), adiponectin (β=-0.36) and leptin (β=0.35); FN BMD with CRP (β=-0.23), ACCP (β=-0.21), PTH (β=-0.35), IL-6 (β=0.37) and leptin (β=0.32); TH BMD with CRP (β=-0.22), AСCP (β=-0.24), PTH (β=-0.30), adiponectin (β=-0.28) and leptin (β=0.42). CONCLUSION: The conducted study showed that BMD in L1-L4, FN and TH is associated with the level of CRP, ACCP, PTH, adiponectin, leptin and IL-6 in postmenopausal women with RA.