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BACKGROUND: The objective of this study was to explore the prevalence of change in bone mineral density (BMD) and the potential risk factors for osteopenia and osteoporosis in rheumatic patients. METHODS: An analytical cross-sectional study design was carried out. For this study, one thousand and seven rheumatic patients were recruited and further accepted for data collection and blood and BMD tests. The potential risk factors for osteopenia and osteoporosis in rheumatic patients were further analyzed by using both logistic regression analysis and random forest (RF) analysis. RESULTS: 41.1% of the male patients aged 50 years or above and 50.8% of postmenopausal patients were osteoporotic in their lumbar spine. Among these patients, the prevalence of osteoporosis in the femoral neck and total hip was 19.4% and 8.9% in men, and 27.6% and 16.5% in women respectively, while more than half of the rheumatic patients had osteopenia in the femoral neck and total hip. For men younger than 50 years and premenopausal women, BMD were lower than the health population in the femoral neck (16.5% and 18.3% respectively) and the total hip (17.4% and 10.4% respectively). Older age, body mass index (BMI) <18.5 kg/m2, female sex and glucocorticoid use were associated with lower BMD in the lumbar spine, femoral neck, and total hip of patients. In RF analysis, age was ranked as the most important factor for osteopenia in the lumbar spine, femoral neck, and total hip of patients, followed by glucocorticoid use and BMI. CONCLUSIONS: More interventions should be given to osteopenia patients because of the higher prevalence when compared with osteoporosis patients. Older age, BMI <18.5 kg/m2, female sex and glucocorticoid use were associated with lower BMD in rheumatic patients. The results from the logistic regression can be supplemented by random forest analysis.
RESUMEN
OBJECTIVE: Ankylosing spondylitis (AS) is a highly heritable disease with HLA-B27 being the strongest susceptible gene. In order to survey the environmental triggers for arthritis development, we used a high-throughput technique to screen the effects of 12,264 chemicals on the HLA-B27 gene promoter. METHODS: Promoter reporter transfectants 293T-HLA-B27 and HeLa-HLA-B27 were tested using robotics with 12,264 chemicals. Chemicals that modulated HLA-B27 promoter activity > 150% or < 40% were selected for further evaluation of IC50/EC50 and cell viability. RESULTS: The primary screening using the 293T-HLA-B27 promoter reporter cell line yielded 5.1% hits that either suppressed (556 chemicals) or enhanced (68 chemicals) the HLA-B27 promoter activity. A secondary reconfirmation screening was carried out with these 624 candidates using HeLa-HLA-B27 promoter reporter cells under several different culture conditions. The yield of positive candidates was 130, of which 47 were derived from natural products. Based on the bio-information of those positive natural products, 21 chemicals were selected for analysis by dose-response IC50/EC50 experiments. Eight compounds showed potential pharmacological activities. Two suppressors are both derived from an herbal medicine (lei gong teng) that has been used for decades to treat immune diseases. The 6 activators all belonged to a group of chemicals known as flavonoids, widely distributed among dietary fruits and vegetables. CONCLUSION: Several common dietary products that contain certain flavonoids might be environmental risk factors for AS; the Chinese traditional herb lei gong teng might be a potential drug for patients who are HLA-B27-positive. These results provide new research directions for the pathogenesis and therapeutics of AS.