Association between Sclerostin and Bone Mineral Density in a Mexican Sample of Women with Rheumatoid Arthritis: A Pilot Study

Introduction/objectives: Rheumatoid arthritis (RA) is associated with decreased bone mass and increased risk of fractures. However, mechanisms underlying this association are not fully understood. Thus, we quantified serum levels of sclerostin, a glycoprotein that inhibits bone formation, and determined its association with bone mineral density (BMD) and disease progression in RA patients. Method: Forty-eight women (aged 25-83 years) with RA and 15 healthy women (aged-matched) were recruited to determine the association between serum sclerostin and BMD at femoral and vertebral level (L1-L4), by DEXA, body mass index (BMI), disease duration, disease activity score (DAS 28), C-Reactive protein and rheumatoid factor. Spearman correlation analyses were performed to determine the association between sclerostin and BMD and the additional variables listed above. A multivariate analysis was used to adjust for confounders. Results: Serum sclerostin was not significantly different between RA patients and controls (22.59 ± 2.13 vs 19.49 ± 3.1 pmol/L). A positive correlation was found between serum sclerostin and femoral BMD (r=0.343, P=0.017), but not BMD at vertebral level. Using a multivariate analysis, the positive correlation was conserved between serum sclerostin and femoral BMD (P=0.002). There was not a significant association between sclerostin and the other variables studied. Conclusions: While serum sclerostin levels were not significantly different between RA patients and controls, this study showed a positive correlation between serum sclerostin and femoral BMD in a small Mexican sample of women with RA. Further studies are needed to evaluate whether serum sclerostin is associated with risk of fracture in RA patients.