Musculoskeletal Research Laboratory, Department of Kinesiology and Health Promotion, California State Polytechnic University, 3801 West Temple Avenue, Pomona, CA, 91765, USA.
Department of Physical Education, National Pingtung University, Pingtung, Taiwan.
Osteoporos Int. 2022 Mar;33(3):673-683. doi: 10.1007/s00198-021-06201-0. Epub 2021 Oct 16.
The rationale was to determine whether body mass index (BMI) is a predictor of bone bending strength and bone mineral density (BMD) in young sedentary women. Results show that BMI is not a predictor of bone bending strength and that young women with low BMI also have low BMD.
The purpose of this study was to determine whether body mass index (BMI) is a predictor of tibial or ulnar bending strength and bone mineral density (BMD) in sedentary women.
Sedentary women (n = 34), age 19-27 years, with low BMI (LBMI < 18.5 kg/m, n = 16), and normal or high BMI (NHBMI between 18.5 and 29.9 kg/m, n = 18) participated as study subjects. Study outcomes included tibial and ulnar bending strength (EI in Nm) using a non-invasive mechanical response tissue analyzer (MRTA); BMD and bone mineral content (BMC) of the whole body (WB), femoral neck (FN), total hip (TH), lumbar spine 1-4 (LS1-4), and ulna; and bone turnover biomarkers.
The LBMI group have lower (p < 0.01) body weight [group difference (Δ) = 32.0%], lean mass (LM) (Δ = 23.1%), fat mass (FM) (Δ = 77.2%), and tibial bending strength (Δ = 22.0%), compared to the NHBMI. The LBMI group also have lower (all p < 0.025) BMC in WB (Δ = 19.9%), FN (Δ = 20.1%) and TH (Δ = 19.0%), compared to the NHMBI, not in BMD results. Multivariate regression analysis shows that significant predictors of tibial bending strength are tibia length (adjusted R = .341), age (adjusted R = .489), ulna BMD (adjusted R = .536), and LM (adjusted R = .580). BMI was positively correlated with tibial EI (p < 0.05), height, weight, FM, LM, body fat% (all p < 0.01), and BMD of WB, FN, TH, and LS 1-4 (p < 0.05 or < 0.01).
Our results show that BMI is not a significant predictor of tibial or ulnar bending strength in young sedentary women.
本研究旨在确定体重指数（BMI）是否是久坐女性胫骨或桡骨弯曲强度和骨矿物质密度（BMD）的预测因子。
本研究纳入了 34 名年龄在 19-27 岁之间的久坐女性，其中低 BMI（LBMI＜18.5kg/m，n=16）和正常或高 BMI（NHBMI 为 18.5-29.9kg/m，n=18）。研究结果包括使用非侵入性机械响应组织分析仪（MRTA）测量的胫骨和桡骨弯曲强度（EI，单位为 Nm）；全身（WB）、股骨颈（FN）、总髋（TH）、腰椎 1-4（LS1-4）和桡骨的 BMD 和骨矿物质含量（BMC）；以及骨转换生物标志物。
LBMI 组的体重[组间差异（Δ）=32.0%]、瘦体重（LM）（Δ=23.1%）、脂肪量（FM）（Δ=77.2%）和胫骨弯曲强度（Δ=22.0%）均显著低于 NHBMI 组（均 P＜0.01）。与 NHMBI 相比，LBMI 组的 WB（Δ=19.9%）、FN（Δ=20.1%）和 TH（Δ=19.0%）的 BMC 也较低（均 P＜0.025），但 BMD 结果无差异。多元回归分析显示，胫骨弯曲强度的显著预测因子为胫骨长度（调整 R=0.341）、年龄（调整 R=0.489）、桡骨 BMD（调整 R=0.536）和 LM（调整 R=0.580）。BMI 与胫骨 EI（P＜0.05）、身高、体重、FM、LM、体脂百分比（均 P＜0.01）以及 WB、FN、TH 和 LS1-4 的 BMD 呈正相关（均 P＜0.05 或＜0.01）。
本研究结果表明，BMI 不是久坐年轻女性胫骨或桡骨弯曲强度的重要预测因子。
