Table 2_Thoracic vertebral bone mineral density measured by quantitative computed tomography is associated with fracture risk in lung cancer screening populations: a prospective cohort study.docx

BackgroundChest low-dose computed tomography (LDCT) is extensively utilized for lung cancer screening, offering a concurrent opportunity to assess thoracic vertebral bone mineral density (BMD) using quantitative computed tomography (QCT). Nonetheless, the value of thoracic BMD (TBMD) in estimating the risk of fractures within this population remains underexplored.
PurposeWe sought to assess the association between fractures and QCT-based TBMD derived from chest LDCT in a lung cancer screening population.
Materials and methodsA prospective study was conducted involving 546 adults aged 40 to 74 years who were enrolled in a lung cancer screening program between 2017 and 2021. TBMD and lumbar BMD (LBMD) were assessed from chest LDCT scans using QCT. Self-reported incident fractures were recorded over a 3-year period, and vertebral fractures (VFs) were evaluated on follow-up CT. Binary logistic regression models and area under the curve (AUC) analyses were utilized to develop and compare the models incorporating TBMD, LBMD, and FRAX for estimating fracture risk.
ResultsOut of the total participants, 323 individuals (59.2%) were found to have VFs, while 16 individuals (2.9%) reported experiencing incident fractures over a period of three years. In unadjusted logistic regression analyses, TBMD was associated with CT-detected VFs (OR = 0.955; 95% CI: 0.947 - 0.963). After adjusting for age and current smoking, TBMD remained associated with CT-detected VFs (OR = 0.953; 95% CI: 0.944 - 0.962). The optimal TBMD threshold for CT-detected VFs was 124 mg/cm3, with a sensitivity of 79.3%, a specificity of 70.9% and AUC of 0.823. Notably, self-reported incident fractures were significantly associated with TBMD (OR = 0.982; 95% CI: 0.965–0.999), independent of adjustment for excessive alcohol consumption (OR = 0.982; 95% CI: 0.965–0.999). The optimal TBMD threshold for self-reported incident fractures was determined to be 94 mg/cm3, with a sensitivity of 62.5%, a specificity of 77.0%, and an AUC of 0.678.
ConclusionQCT-based TBMD derived from LDCT scans might be a feasible and effective tool for identifying individuals with VFs and an elevated risk of incident fracture, without additional radiation exposure in lung cancer screening populations.

背景：胸部低剂量计算机断层扫描（Chest low-dose computed tomography, LDCT）已被广泛用于肺癌筛查，同时可借助定量计算机断层扫描（quantitative computed tomography, QCT）评估胸椎骨密度（thoracic vertebral bone mineral density, TBMD）。不过，该人群中胸椎骨密度（TBMD）在骨折风险预测中的价值仍有待深入探索。
目的：本研究旨在评估肺癌筛查人群中，基于胸部LDCT获取的QCT测量TBMD与骨折之间的关联。
材料与方法：本研究为前瞻性研究，纳入2017至2021年间参与肺癌筛查项目的546名年龄介于40至74岁的成年人。通过QCT对胸部LDCT扫描图像进行TBMD与腰椎骨密度（lumbar BMD, LBMD）测量。在为期3年的随访期间，记录受试者自我报告的新发骨折，并通过随访CT评估椎体骨折（vertebral fractures, VFs）。采用二元逻辑回归模型与曲线下面积（area under the curve, AUC）分析，构建并对比纳入TBMD、LBMD及FRAX的骨折风险预测模型。
结果：全部受试者中，323人（59.2%）检出VFs，16人（2.9%）报告3年随访期间出现新发骨折。未校正的逻辑回归分析显示，TBMD与CT检出的VFs显著相关（优势比OR=0.955；95%置信区间CI：0.947~0.963）。校正年龄与当前吸烟状态后，TBMD仍与CT检出的VFs显著相关（OR=0.953；95%CI：0.944~0.962）。CT检出VFs的最佳TBMD阈值为124 mg/cm³，灵敏度为79.3%，特异度为70.9%，AUC为0.823。值得注意的是，自我报告的新发骨折与TBMD显著相关（OR=0.982；95%CI：0.965~0.999），在校正过量饮酒史后该关联仍保持显著（OR=0.982；95%CI：0.965~0.999）。自我报告新发骨折的最佳TBMD阈值为94 mg/cm³，灵敏度为62.5%，特异度为77.0%，AUC为0.678。
结论：基于肺癌筛查人群胸部LDCT获取的QCT测量TBMD，可作为一种无需额外辐射暴露的可行且有效的工具，用于识别存在椎体骨折及新发骨折风险升高的个体。