Department of Physiological Sciences, University of Arizona, Tucson, AZ 85721-0093, USA.
J Bone Miner Res. 2011 Sep;26(9):2217-25. doi: 10.1002/jbmr.414.
Childhood obesity is an established risk factor for metabolic disease. The influence of obesity on bone development, however, remains controversial and may depend on the pattern of regional fat deposition. Therefore, we examined the associations of regional fat compartments of the calf and thigh with weight-bearing bone parameters in girls. Data from 444 girls aged 9 to 12 years from the Jump-In: Building Better Bones study were analyzed. Peripheral quantitative computed tomography (pQCT) was used to assess bone parameters at metaphyseal and diaphyseal sites of the femur and tibia along with subcutaneous adipose tissue (SAT, mm(2) ) and muscle density (mg/cm(3) ), an index of skeletal muscle fat content. As expected, SAT was positively correlated with total-body fat mass (r = 0.87-0.89, p < .001), and muscle density was inversely correlated with total-body fat mass (r = -0.24 to -0.28, p < .001). Multiple linear regression analyses with SAT, muscle density, muscle cross-sectional area, bone length, maturity, and ethnicity as independent variables showed significant associations between muscle density and indices of bone strength at metaphyseal (β = 0.13-0.19, p < .001) and diaphyseal (β = 0.06-0.09, p < .01) regions of the femur and tibia. Associations between SAT and indices of bone strength were nonsignificant at all skeletal sites (β = 0.03-0.05, p > .05), except the distal tibia (β = 0.09, p = .03). In conclusion, skeletal muscle fat content of the calf and thigh is inversely associated with weight-bearing bone strength in young girls.
儿童肥胖是代谢性疾病的既定危险因素。然而，肥胖对骨骼发育的影响仍存在争议，其可能取决于区域性脂肪沉积的模式。因此，我们研究了小腿和大腿的局部脂肪与女孩承重骨参数之间的相关性。分析了来自 Jump-In：Building Better Bones 研究的 444 名 9 至 12 岁女孩的数据。使用外周定量计算机断层扫描 (pQCT) 评估股骨和胫骨骨干和干骺端部位的骨参数，以及皮下脂肪组织 (SAT，mm²) 和肌肉密度 (mg/cm³)，这是骨骼肌肉脂肪含量的指标。正如预期的那样，SAT 与全身脂肪质量呈正相关 (r=0.87-0.89，p<0.001)，而肌肉密度与全身脂肪质量呈负相关 (r=-0.24 至-0.28，p<0.001)。以 SAT、肌肉密度、肌肉横截面积、骨长、成熟度和种族为自变量进行多元线性回归分析显示，肌肉密度与股骨骨干和干骺端 (β=0.13-0.19，p<0.001) 和胫骨骨干和干骺端 (β=0.06-0.09，p<0.01) 部位的骨强度指数之间存在显著相关性。除了胫骨远端 (β=0.09，p=0.03) 外，SAT 与所有骨骼部位的骨强度指数之间无显著相关性 (β=0.03-0.05，p>0.05)。总之，小腿和大腿的骨骼肌脂肪含量与年轻女孩的承重骨强度呈负相关。
