Sowers M F, Kshirsagar A, Crutchfield M M, Updike S
University of Michigan, Department of Epidemiology, School of Public Health, Ann Arbor.
Am J Epidemiol. 1992 Aug 1;136(3):257-65. doi: 10.1093/oxfordjournals.aje.a116491.
Body composition (fat and lean compartments) and bone mineral density were measured in 246 healthy premenopausal women, aged 20-40 years, residing in Tecumseh, Michigan. Body composition was measured using four-point bioelectrical impedance and values for fat and lean compartments categorized into tertiles. Additionally, each woman was classified into one of nine different cells based on her location within a 3 x 3 table which reflects the joint distribution of both fat and lean compartments. Bone mineral density of the proximal femur, including the femoral neck and trochanter, was measured using dual photon densitometry. The mean femoral neck bone mineral density values increased significantly and linearly for each tertile of muscle mass (0.90, 0.95, and 1.02 g/cm2, p less than 0.0002). Femoral bone mineral density increased significantly but not linearly as the fat compartment progressed from the lowest to the highest tertile (0.95, 0.93, and 0.99 g/cm2). Bone mineral density of the proximal femur was similar and significantly greater in the high muscle/low fat and high muscle/high fat body composition subgroups compared with bone mineral density in the seven other groups. However, women in the high muscle/low fat subgroup had substantially lower mean weight (67 vs. 91 kg, p less than 0.0001) and mean Quetelet index (22.1 vs. 33.7 kg/m2, p less than 0.0001) than women in the high muscle/high fat subgroup. Bone mineral density values were similar and significantly lower in the following body composition cells: low muscle/low fat, low muscle/medium fat, and low muscle/high fat. Similar findings were observed at the trochanteric site. Low muscle is a risk factor for low bone mineral density in young adult women while higher fat is protective only when associated with substantial muscle.
对居住在密歇根州蒂康塞的246名年龄在20至40岁之间的健康绝经前女性进行了身体成分（脂肪和瘦组织部分）及骨矿物质密度测量。使用四点生物电阻抗法测量身体成分，并将脂肪和瘦组织部分的值分为三分位数。此外，根据每位女性在一个3×3表格中的位置，将其分为九个不同的组之一，该表格反映了脂肪和瘦组织部分的联合分布。使用双能X线吸收法测量近端股骨（包括股骨颈和大转子）的骨矿物质密度。肌肉量三分位数中，平均股骨颈骨矿物质密度值显著且呈线性增加（分别为0.90、0.95和1.02 g/cm²，p<0.0002）。随着脂肪部分从最低三分位数发展到最高三分位数，股骨骨矿物质密度显著增加但并非呈线性（分别为0.95、0.93和0.99 g/cm²）。与其他七个组相比，高肌肉/低脂肪和高肌肉/高脂肪身体成分亚组的近端股骨骨矿物质密度相似且显著更高。然而，高肌肉/低脂肪亚组的女性平均体重（67 vs. 91 kg，p<0.0001）和平均体重指数（22.1 vs. 33.7 kg/m²，p<0.0001）显著低于高肌肉/高脂肪亚组的女性。在以下身体成分组中，骨矿物质密度值相似且显著较低：低肌肉/低脂肪、低肌肉/中等脂肪和低肌肉/高脂肪。在大转子部位也观察到了类似的结果。低肌肉量是年轻成年女性低骨矿物质密度的一个危险因素，而较高的脂肪量只有在与大量肌肉相关时才具有保护作用。
