Daly R M, Bass S L
Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Highway, Burwood, Melbourne, 3125, Australia.
Osteoporos Int. 2006;17(8):1258-67. doi: 10.1007/s00198-006-0114-1. Epub 2006 May 6.
It remains uncertain whether long-term participation in regular weight-bearing exercise confers an advantage to bone structure and strength in old age. The aim of this study was to investigate the relationship between lifetime sport and leisure activity participation on bone material and structural properties at the axial and appendicular skeleton in older men (>50 years).
We used dual-energy X-ray absorptiometry (DXA) to assess hip, spine and ultradistal (UD) radius areal bone mineral density (aBMD) (n=161), quantitative ultrasound (QUS) to measure heel bone quality (n=161), and quantitative computed tomography (QCT) to assess volumetric BMD, bone geometry and strength at the spine (L(1)-L(3)) and mid-femur (n=111). Current (>50+ years) and past hours of sport and leisure activity participation during adolescence (13-18 years) and adulthood (19-50 years) were assessed by questionnaire. This information was used to calculate the total time (min) spent participating in sport and leisure activities and an osteogenic index (OI) score for each participant, which provides a measure of participation in weight-bearing activities.
Regression analysis revealed that a greater lifetime (13-50+ years) and mid-adulthood (19-50 years) OI, but not total time (min), was associated with a greater mid-femur total and cortical area, cortical bone mineral content (BMC), and the polar moment of inertia (I (p)) and heel VOS (p ranging from <0.05 to <0.01). These results were independent of age, height (or femoral length) and weight (or muscle cross-sectional area). Adolescent OI scores were not found to be significant predictors of bone structure or strength. Furthermore, no significant relationships were detected with areal or volumetric BMD at any site. Subjects were then categorized into either a high (H) or low/non-impact (L) group during adolescence (13-18 years) and adulthood (19-50+ years) according to their OI scores during each of these periods. Three groups were subsequently formed to reflect weight-bearing impact categories during adolescence and then adulthood: LL, HL and HH. Compared to the LL group, mid-femur total and cortical area, cortical BMC and I (p) were 6.5-14.2% higher in the HH group. No differences were detected between the LL and HL groups.
In conclusion, these findings indicate that long-term regular participation in sport and leisure activities categorized according to an osteogenic index [but not the total time (min) spent participating in all sport and leisure activities] was an important determinant of bone size, quality and strength, but not BMD, at loaded sites in older men. Furthermore, continued participation in weight-bearing exercise in early to mid-adulthood appears to be important for reducing the risk of low bone strength in old age.
长期参与规律的负重运动是否能使老年人的骨骼结构和强度受益仍不确定。本研究的目的是调查老年男性（>50岁）一生中参与体育和休闲活动与轴向和附属骨骼的骨材料及结构特性之间的关系。
我们使用双能X线吸收法（DXA）评估髋部、脊柱和超远端（UD）桡骨的面积骨密度（aBMD）（n = 161），使用定量超声（QUS）测量跟骨质量（n = 161），并使用定量计算机断层扫描（QCT）评估脊柱（L1-L3）和股骨中段的体积骨密度、骨几何形状和强度（n = 111）。通过问卷调查评估当前（>50岁以上）以及青少年期（13 - 18岁）和成年期（19 - 50岁）过去参与体育和休闲活动的时长。这些信息用于计算每位参与者参与体育和休闲活动的总时长（分钟）以及成骨指数（OI）得分，该得分可衡量参与负重活动的程度。
回归分析显示，一生中（13 - 50岁以上）和成人生中期（19 - 50岁）较高的OI得分，而非总时长（分钟），与股骨中段更大的总面积和皮质面积、皮质骨矿物质含量（BMC）、极惯性矩（Ip）以及跟骨VOS相关（p值范围从<0.05至<0.01）。这些结果不受年龄、身高（或股骨长度）和体重（或肌肉横截面积）的影响。未发现青少年OI得分是骨结构或强度的显著预测指标。此外，在任何部位均未检测到与面积或体积骨密度的显著关系。然后根据青少年期（13 - 18岁）和成年期（19 - 50岁以上）的OI得分，将受试者分为高（H）或低/非负重（L）组。随后形成三组以反映青少年期和成年期的负重影响类别：LL、HL和HH。与LL组相比，HH组的股骨中段总面积和皮质面积、皮质BMC和Ip高6.5 - 14.2%。LL组和HL组之间未检测到差异。
总之，这些发现表明，根据成骨指数分类的长期规律参与体育和休闲活动（而非参与所有体育和休闲活动的总时长）是老年男性负重部位骨大小、质量和强度（而非骨密度）的重要决定因素。此外，在成年早期至中期持续参与负重运动对于降低老年期低骨强度风险似乎很重要。
