This study aimed to clarify changes in the prevalence of rheumatic diseases in Shantou, China, in the past 3 decades and validate whether stair-climbing is a risk factor for knee pain and knee osteoarthritis (KOA). The World Health Organization-International League Against Rheumatism Community Oriented Program for Control of Rheumatic Diseases (COPCORD) protocol was implemented. In all, 2337 adults living in buildings without elevators and 1719 adults living in buildings with elevators were surveyed. The prevalence of rheumatic pain at any site and in the knee was 15.7% and 10.2%, respectively; both types of pain had a significantly higher incidence in residents of buildings without elevators than was reported by people who lived in buildings with elevators (14.9% vs. 10.6% and 11.32% vs. 8.82%, respectively) (both P < 0.0001). The prevalence of rheumatic pain in the neck, lumbar spine, shoulder, elbow, and foot was 5.6%, 4.5%, 3.1%, 1.4%, and 1.8%, respectively; these findings were similar to the data from the 1987 rural survey, but were somewhat lower than data reported in the urban and suburban surveys of the 1990s, with the exception of neck and lumbar pain. The prevalence of KOA, gout, and fibromyalgia was 7.10%, 1.08%, and 0.07%, respectively, and their prevalence increased significantly compared with those in previous studies from the 20th century. There were no significant differences in the prevalence of rheumatoid arthritis (RA) (0.35%) or ankylosing spondylitis (AS) (0.31%) compared to that reported in prior surveys. The prevalence of KOA was higher in for residents of buildings without elevators than that in those who had access to elevators (16–64 years, 5.89% vs. 3.95%, P = 0.004; 16->85 years, 7.64% vs. 6.26%, P = 0.162). The prevalence of RA and AS remained stable, whereas that of KOA, gout, and fibromyalgia has increased significantly in Shantou, China, during the past 3 decades. Stair-climbing might be an important risk factor for knee pain and KOA.

ObjectiveThis study aimed to assess the relationship between bone marrow edema (BME) on magnetic resonance imaging (MRI) and bone mineral density (BMD) in patients with ankylosing spondylitis (AS).MethodsThe study included 333 patients with AS who underwent BMD measurements and axial MRI. Additionally, 106 normal controls were included. The modified New York criteria were used as the classification criteria of AS. Clinical, laboratory, and imaging data were collected and analyzed. Lumbar spine and proximal femur BMD were assessed using dual-energy X-ray absorptiometry. Low BMD was defined by a Z-score ≤-2. The Spondyloarthritis Research Consortium of Canada (SPARCC) MRI index was used to assess inflammation at the sacroiliac joint (SIJ) and spine.ResultsAmong the 333 patients, the male:female ratio was 4.6:1, mean patient age was 28.5±10.6 years, and mean disease duration was 7.3±6.8 years. The prevalences of low BMD, osteopenia, and osteoporosis were significantly higher among AS patients than among controls (19.8%, 62.8%, and 5.7% vs. 4.7%, 33.0%, and 0%, respectively, P = 0.000). The BMD values were significantly lower and prevalences of low BMD at both the spine and femur were significantly higher among patients with BME on MRI than among those without BME. Multivariate logistic regression analysis showed that male sex (OR 3.87, 95% CI 1.21–7.36, P = 0.023), high ASDAS-CRP score (OR 2.83, 95% CI 1.36–4.76, P = 0.015), the presence of BME on sacroiliac MRI (OR 2.83, 95% CI 1.77–6.23, P = 0.000) and spinal MRI (OR 4.06, 95% CI 1.96–8.46, P = 0.000), and high grade of sacroiliitis (OR 2.93, 95% CI 1.82–4.45, P = 0.002) were risk factors for low BMD (any site). The SPARCC scores of the SIJ were negatively correlated with femoral BMD (r = -0.22, 95% CI -0.33 to -0.10, P = 0.000). Additionally, the SPARCC scores of the spine were negatively correlated with BMD values (r = -0.23, 95% CI -0.36 to -0.09, P = 0.003) and Z-scores (r = -0.24, 95% CI -0.36 to -0.12, P = 0.001) at the spine.ConclusionLow BMD is common in AS patients. BME on MRI is highly associated with low BMD at both the spine and femur.

The sacroiliac joints (SIJs) are one of the most common sites involved in axial spondyloarthritis (axSpA), and there are few studies on the histopathology of the SIJ in this group of patients.Mononuclear cell infiltrates in the bone marrow and fibrous tissue resembling a pannus formation were the pathological features of early sacroiliitis in our previous study. We undertook a further immunohistological evaluation of these features in patients with axSpA.Biopsy specimens from the SIJ of 6 patients with established ankylosing spondylitis (AS) and 13 patients with nonradiographic axial spondyloarthritis (nr-axSpA) were analyzed. An immunohistological method was performed to examine the macrophages (CD163), T cells (CD3), and B cells (CD20).Mononuclear cell infiltrates in the bone marrow were observed in only 6 patients with nr-axSpA. Fibrous tissue was observed in all patients with established AS and 9 patients with nr-axSpA. Macrophage, T cell, and B cell infiltrates could be detected in both the bone marrow and fibrous tissue. All bone marrow specimens from 6 nr-axSpA patients exhibited CD163+ macrophage infiltrates; of these, 5 exhibited CD20+ B cell infiltrates and 3 exhibited CD3+ T cell infiltrates. Among the fibrous tissue specimens, all exhibited macrophage infiltrates, 9 exhibited B cell infiltrates, and 4 exhibited T cell infiltrates.In addition to macrophages and T cells, B cells are also involved in active sacroiliitis in patients with axSpA.

ObjectiveTo evaluate the clinical characteristics of juvenile-onset non-radiographic axial spondyloarthritis (nr-axSpA) and to investigate risk factors associated with progression to juvenile-onset ankylosing spondylitis (JoAS).MethodsA nested case–control study was conducted using the retrospectively collected data of 106 patients with juvenile-onset nr-axSpA (age at disease onset, <16 years) in the Clinical characteristic and Outcome in Chinese Axial Spondyloarthritis study cohort. Baseline demographic and clinical characteristics and prognosis were reviewed. Logistic regression analyses were performed to investigate risk factors associated with progression to JoAS.ResultsOverall, 58.5% of patients with juvenile-onset nr-axSpA presented with peripheral symptoms at disease onset. In 82.1% of these patients, axial with peripheral involvement occurred during the disease course. The rate of disease onset at >12 years and disease duration of ≤10 years were significantly higher in those with progression to JoAS than in those without progression to JoAS (83.0% vs 52.8%, p=0.001; 92.5% vs 56.6%, p<0.001, respectively). Multivariable logistic regression analysis revealed that inflammatory back pain (IBP) (OR 13.359 (95% CI 2.549 to 70.013)), buttock pain (OR 10.171 (95% CI 2.197 to 47.085)), enthesitis (OR 7.113 (95% CI 1.670 to 30.305)), elevated baseline C reactive protein (CRP) levels (OR 7.295 (95% CI 1.984 to 26.820)) and sacroiliac joint-MRI (SIJ-MRI) positivity (OR 53.821 (95% CI 9.705 to 298.475)) were significantly associated with progression to JoAS.ConclusionPeripheral involvement was prevalent in juvenile-onset nr-axSpA. IBP, buttock pain, enthesitis, elevated baseline CRP levels and SIJ-MRI positivity in patients with the disease are associated with higher risk of progression to JoAS.

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