THE EFFECT OF BODY SIZE AND COMPOSITION ON LUMBAR SPINE TRABECULAR BONE SCORE IN MORPHOLOGICALLY DIVERSE SUBJECTS

Aim: The trabecular bone score (TBS) is a tool for assessing bone quality and health. Current TBS algorithm corrects for body mass index (BMI), as a proxy of regional tissue thickness. However, this approach fails to consider BMI inaccuracies due to individual differences in body stature, composition and somatotype. This study investigated the relationship between TBS and body size and composition in subjects with a normal BMI, but with large morphological diversity in body fatness and height. Methods: Young male subjects (n=97; age 17.2±1.0 years), including ski jumpers (n=25), volleyball players (n=48) and non-athletes (controls n=39), were recruited. The TBS was determined from L1-L4 dual-energy X-ray absorptiometry (DXA) scans using TBSiNsight software. Results: TBS correlated negatively with height and tissue thickness in the L1-L4 area in ski jumpers (r= -0.516 and r= -0.529), volleyball players (r= -0.525 and r= -0.436), and the total group (r=-0.559 and r=-0.463), respectively. Multiple regression analyses revealed that height, L1-L4 soft tissue thickness, fat mass and muscle mass were significant determinants of TBS (R2= 0.587, p<0.001). L1-L4 soft tissue thickness explained 27% and height 14% of the TBS variance. Conclusion: The negative association of TBS and both features suggests that a very low L1-L4 tissue thickness may lead to overestimation of the TBS, while tall stature may have the opposite effect. It seems that the utility of the TBS as a skeletal assessment tool in lean and/or tall young male subjects could be improved if tissues thickness in the lumbar spine area and stature instead of BMI were considered in the algorithm.研究目的：小梁骨评分（Trabecular Bone Score, TBS）是评估骨质量与健康状况的专用工具。当前TBS算法以体质量指数（Body Mass Index, BMI）作为局部组织厚度的替代指标进行校正，但该方法未考虑因个体身高、身体组成及体型差异导致的BMI测量不准确问题。本研究旨在探究在BMI正常，但体脂与身高存在显著形态学差异的人群中，TBS与身体尺寸及身体组成之间的关联。 研究方法：本研究共招募97名青年男性受试者，年龄为17.2±1.0岁，其中包括跳台滑雪运动员25名、排球运动员48名及非运动员对照39名。采用TBSiNsight软件，基于L1-L4椎体的双能X线吸收测定法（Dual-energy X-ray absorptiometry, DXA）扫描结果计算TBS值。 研究结果：在跳台滑雪运动员群体中，TBS与身高及L1-L4区域组织厚度呈显著负相关（相关系数r分别为-0.516与-0.529）；排球运动员群体中该相关系数分别为-0.525与-0.436；全部受试者群体中则分别为-0.559与-0.463。多元回归分析结果显示，身高、L1-L4软组织厚度、脂肪量及肌肉量是影响TBS的显著因素（决定系数R²=0.587，p<0.001）。其中L1-L4软组织厚度可解释27%的TBS变异度，身高可解释14%的TBS变异度。 研究结论：上述负相关关系提示，L1-L4区域组织厚度极低时可能导致TBS被高估，而身材高挑则会产生相反的影响效果。若在TBS算法中纳入腰椎区域组织厚度与身高指标，而非仅使用BMI，则可提升该工具在体瘦和/或身材高挑的青年男性群体中进行骨骼评估的实用性。