女性不同骨骼部位骨密度峰值和参考图的建立方法

目的建立女性不同骨骼部位骨密度(BMD)参考图和确定峰值BMD(PBMD). 方法 用DXA QDR 4500A型扇形束骨密度仪测量3378例5～96岁女性腰椎前后位(AP)和仰卧侧位、髋部和前臂的BMD,用8种回归模型拟合BMD随年龄的变化,找出最佳拟合模型方程建立参考图和确定PBMD.结果三次回归模型拟合程度最佳,即方程的决定系数(R2)最大.我们应用拟合曲线建立了BMD参考图,拟合曲线方程计算各骨骼部位最高的BMD(A方法)和BMD最高的5岁年龄组(B方法)及年龄横断面(C方法)计算PBMD,发现在大多数骨骼部位,三种方法计算的PBMD的差异有显著性.结论此研究建立了女性不同骨骼部位BMD参考图.应用拟合曲线方程计算PBMD(A方法)可获得符合骨骼部位特异性的真正的PBMD,不同方法计算PBMD将对PBMD和诊断骨质疏松产生严重影响.

Establisbment of bone mineral density reference plots and peaks for different skeletal sites in women

Objective To establish the bone mineral density (BMD) reference plots and determine the peaks of different skeletal sites in women. Methods BMDs of anteroposterior (AP) and supine lateral lumbar spines, hip, and forearm were measured using DXA QDR 4500A fan beam bone densitometer in 3378 women aged 5 to 96 years. Age-related changes were fitted in the whole woman population by eight kinds of regression models. The best model equation of fitting was found for establishing the reference plots and determining the peak BMDs. Results The cubic regression model was found to fit best in analyzing the age-dependent variations of BMD at various sites; i.e., the equation had the largest coefficient of determination ( R2 ) . We utilized the curve-fitting to establish BMD reference plots, and the curve-fitting equations to calculate the highest BMDs at various skeletal sites using three methods of calculation, method A for actual peak BMD; method B for peak BMD of each five-year age group ; and method C which is based on cross-section of age. Comparison of the three methods showed significant differences between them at most skeletal sites. Conclusion We have established the BMD reference plots for the various skeletal sites in women. Curve-fitting equations can be utilized to calculate actual peak BMDs specific to individual sites, and the use of different methods for calculating peak BMD may have a significant impact on both peak BMD and the diagnosis of osteoporosis.