Smith L, Thomas E L, Bell J D, Hamer M
Department of Epidemiology and Public Health, University College London, London, UK.
Metabolic and Molecular Imaging Group, MRC Clinical Sciences Centre, Imperial College London, London, UK.
BMJ Open. 2014 Jun 10;4(6):e005476. doi: 10.1136/bmjopen-2014-005476.
To investigate the association between objectively measured sitting and standing, using a postural allocation technique, with MRI-assessed body composition.
The present study was a cross-sectional pilot study.
Participants were examined at one centre located in London, UK.
Normal weight Caucasian women (30.9±6.1 years; body mass index (BMI), 22.9±3.4 kg/m(2)) with desk-bound occupations were recruited to minimise variability in body composition outcomes. A convenience sample of 12 women was recruited in January 2014 from University College London.
For each participant a number of body composition variables were attained from a single whole-body MRI session. Main outcome variables included: total and liver adiposity, visceral/subcutaneous fat ratio and BMI. Main exposure variables included: average sitting time, standing:sitting ratio and step count. Pearson correlations were carried out to examine associations between different activity categories and body composition variables.
There were significant correlations between average daily sitting and liver adiposity and visceral/subcutaneous abdominal fat ratio (r=0.66 and 0.64, respectively); standing:sitting ratio was moderately correlated with liver adiposity and visceral/subcutaneous abdominal fat ratio (r=-0.53 and -0.45); average daily step count was moderately correlated with liver adiposity, total adiposity and visceral/subcutaneous abdominal fat ratio (r=-0.45, -0.46 and -0.51, respectively).
This pilot study has provided preliminary evidence of relationships between objectively measured sitting and standing and precise measures of body composition.
采用姿势分配技术，研究客观测量的坐姿和站姿与磁共振成像（MRI）评估的身体成分之间的关联。
本研究为横断面试点研究。
在英国伦敦的一个中心对参与者进行检查。
招募从事案头工作的体重正常的白人女性（年龄30.9±6.1岁；体重指数（BMI）22.9±3.4kg/m²），以尽量减少身体成分结果的变异性。2014年1月从伦敦大学学院招募了12名女性的便利样本。
对每位参与者，通过单次全身MRI检查获得多项身体成分变量。主要结果变量包括：总体脂和肝脏脂肪含量、内脏/皮下脂肪比率和BMI。主要暴露变量包括：平均坐姿时间、站立与坐姿比率和步数。采用Pearson相关性分析来检验不同活动类别与身体成分变量之间的关联。
平均每日坐姿与肝脏脂肪含量以及内脏/皮下腹部脂肪比率之间存在显著相关性（分别为r = 0.66和0.64）；站立与坐姿比率与肝脏脂肪含量以及内脏/皮下腹部脂肪比率呈中度相关（分别为r = -0.53和-0.45）；平均每日步数与肝脏脂肪含量、总体脂以及内脏/皮下腹部脂肪比率呈中度相关（分别为r = -0.45、-0.46和-0.51）。
这项试点研究提供了初步证据，表明客观测量的坐姿和站姿与身体成分的精确测量之间存在关联。
