Background: Rheumatoid arthritis (RA) is a systemic autoimmune disease that increased bone resorption. Periodontal disease (PD) is an associated risk factor of RA. Studies suggest an association between bone markers such as the dickkopf-related protein 1 (DKK-1) and progression of radiological damage. We aimed to evaluate the marker DKK-1, its polymorphisms in patients with early rheumatoid arthritis (eRA), and its association with rheumatic, radiological, and periodontal variables.
Methods: This is a cross-sectional study. Samples were obtained from 63 patients with eRA. Radiographs of hands and feet were evaluated by Sharp-van der Heijde score (SHS) and Simple Erosion Narrowing Score (SENS). Serum DKK-1 levels and high-resolution fusion analysis was used for polymorphisms (rs1896368, rs1896367, rs1528873). Bivariate analyses were performed.
Results: Individuals heterozygous for rs1896367 had more frequent erosions (p = 0.026) and joint space narrowing (p = 0.005) in the feet, higher SHS (p = 0.016), and higher SENS (p ≤ 0.001). Patients homozygous for rs1896368 had less frequent joint space narrowing in hands and feet as assessed by SHS and less presence of erosions by SENS (odds ratio, 0.04; 95% confidence interval, 0.00-0.93; p < 0.05). The presence of PD was associated with the homozygous of rs1896367 (p = 0.009) and the heterozygous of rs1896368 (p = 0.033).
Conclusions: Polymorphism rs1896367 seems to be associated with greater radiological compromise; rs1896368 confers protection against bone damage in Colombian eRA patients.