Yang Li-chen, Hu Jing, Lan Yan, Yang Yan-hua, Zhang Qian, Piao Jian-hua
National Institute for Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
Zhonghua Yu Fang Yi Xue Za Zhi. 2009 Dec;43(12):1077-80.
To assess bone mineral content (BMC) of 15 - 17 year-old dancers and high school females and analyze the relationship between physical activity status and BMC.
Sixty dancers and 77 healthy controls aged 15 - 17 years old were enrolled in our study. BMC in the total body and forearm were measured by dual-energy X-ray absorptiometry (DEXA) while body weight and height were also measured. Physical activity information was collected by "one-year physical activity questionnaire".
The physical activity level (PAL) and the average daily energy expenditure (EE) of dancers were all higher than controls (PAL: 2.17 +/- 0.34 vs 1.63 +/- 0.34, t = 7.283; EE: (6876.43 +/- 1036.72) kJ vs (5388.43 +/- 920.83) kJ, t = 7.214, both P values < 0.01). The dancers showed lower BMC/height at total body and arms compared with the controls (the total body BMC/height was (13.896 +/- 1.308) vs (14.494 +/- 1.272) g/cm, F = -2.563); and the BMC/height of left and right arm were (0.779 +/- 0.088) vs (0.829 +/- 0.101) g/cm (F = -2.892) and (0.766 +/- 0.093) vs (0.829 +/- 0.097) g/cm (F = -3.650) respectively, all these P values were < 0.01.Yet after adjusting age and BMI, the dancers showed higher BMC/height at total body and legs, the corresponding values were (14.550 +/- 0.146) vs (13.947 +/- 0.131) g/cm (F = 7.868), (2.681 +/- 0.033) vs (2.389 +/- 0.030) g/cm (F = 36.520), (2.821 +/- 0.031) vs (2.450 +/- 0.028) g/cm (F = 65.279), all these P values were < 0.01. While no differences were found with controls at non-weight bearing sites (arms). Daily period (h) of training was significantly related to BMC/height of legs, total body (r value were 0.618, 0.448 and 0.554 respectively, all the P values < 0.01), while the history of training was also correlated with BMC/height of two legs (r value were 0.38 and 0.304 respectively, both P values < 0.05).
The adolescent dancers showed higher BMC after adjusting age and BMI, which was attributed to the long-term high level weight-bearing physical activity.
评估15 - 17岁舞蹈演员和高中女生的骨矿物质含量（BMC），并分析身体活动状况与BMC之间的关系。
本研究纳入了60名15 - 17岁的舞蹈演员和77名健康对照者。采用双能X线吸收法（DEXA）测量全身和前臂的BMC，同时测量体重和身高。通过“一年身体活动问卷”收集身体活动信息。
舞蹈演员的身体活动水平（PAL）和平均每日能量消耗（EE）均高于对照组（PAL：2.17±0.34对1.63±0.34，t = 7.283；EE：（6876.43±1036.72）kJ对（5388.43±920.83）kJ，t = 7.214，P值均<0.01）。与对照组相比，舞蹈演员全身和手臂的BMC/身高较低（全身BMC/身高为（13.896±1.308）对（14.494±1.272）g/cm，F = -2.563）；左右手臂的BMC/身高分别为（0.779±0.088）对（0.829±0.101）g/cm（F = -2.892）和（0.766±0.093）对（0.829±0.097）g/cm（F = -3.650），所有这些P值均<0.01。然而，在调整年龄和BMI后，舞蹈演员全身和腿部的BMC/身高较高，相应值分别为（14.550±0.146）对（13.947±0.131）g/cm（F = 7.868），（2.681±0.033）对（2.389±0.030）g/cm（F = 36.520），（2.821±0.031）对（2.450±0.028）g/cm（F = 65.279），所有这些P值均<0.01。而在非承重部位（手臂）与对照组未发现差异。每日训练时长（小时）与腿部、全身的BMC/身高显著相关（r值分别为0.618、0.448和0.554，所有P值<0.01），而训练史也与双腿的BMC/身高相关（r值分别为0.38和0.304，P值均<0.05）。
青少年舞蹈演员在调整年龄和BMI后显示出较高的BMC，这归因于长期高水平的负重身体活动。
