[Baseline characteristics of the West China Bone Health Cohort and analysis on the influencing factors of osteoporosis and fragility fracture risk].

Objective: To characterize the baseline features of the West China Bone Health Cohort and to identify major factors of osteoporosis and fragility fractures. Methods: A prospective epidemiological survey was conducted based on outpatients at West China Fourth Hospital of Sichuan University and community residents from Hongguang, Chengdu. Demographic characteristics, lifestyle factors, biochemical indicators, and imaging data were collected (etiological study). Medical records of inpatients admitted to the osteoporosis department of the same hospital between 2017 and 2024 were retrospectively analyzed (prognostic study). Descriptive analysis, univariate and multivariate logistic regression model were performed to explore risk factors of osteoporosis and fragility fractures. Results: A total of 3 918 participants was enrolled in the prospective survey, and 6 737 inpatients were included in the retrospective analysis. Multivariate logistic regression analysis showed that in the prospective survey, age (aOR=1.06, 95%CI: 1.05-1.08), female sex (aOR=10.76, 95%CI: 7.39-15.94), and smoking (former smoking: aOR=1.58, 95%CI: 1.02-2.45; current smoking: aOR=1.90, 95%CI: 1.21-2.97) were risk factors for osteoporosis, while BMI (aOR=0.87, 95%CI: 0.84-0.89) and education (aOR=0.80, 95%CI: 0.65-0.99) were protective factors. In the retrospective analysis, age (aOR=1.07, 95%CI: 1.06-1.08) and monocyte count (aOR=1.91, 95%CI: 1.03-3.54) were positively associated with the risk of fragility fracture, while lymphocyte count (aOR=0.83, 95%CI: 0.75-0.92) was negatively associated with the risk. Conclusions: Age, female sex, smoking, low BMI, and low educational attainment were the main factors associated with osteoporosis, whereas age and abnormal inflammatory markers were closely related to fragility fractures. These findings highlight the importance of early identification and intervention among high-risk populations.