Collings Paul J, Brage Soren, Bingham Daniel D, Costa Silvia, West Jane, McEachan Rosemary R C, Wright John, Barber Sally E
1Bradford Institute for Health Research, Bradford NHS Foundation Trust, Bradford, UNITED KINGDOM; 2MRC Epidemiology Unit, University of Cambridge, Cambridge, UNITED KINGDOM; 3School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, UNITED KINGDOM; and 4UKCRC Centre for Diet and Activity Research (CEDAR), School of Clinical Medicine, University of Cambridge, Cambridge, UNITED KINGDOM.
Med Sci Sports Exerc. 2017 May;49(5):930-938. doi: 10.1249/MSS.0000000000001180.
This study aimed to investigate associations of objectively measured physical activity (PA) and sedentary time with adiposity in a predominantly biethnic (South Asian and White British) sample of young children.
The sample included 333 children age 11 months to 5 yr who provided 526 cross-sectional observations for PA and body composition. Total PA volume (vector magnitude counts per minute), daily time at multiple intensity levels (the cumulative time in activity >500, >1000, >1500, …, >6000 counts per minute), and time spent sedentary (<820 counts per minute), in light PA (820-3907 counts per minute) and in moderate-to-vigorous PA (≥3908 counts per minute) were estimated with triaxial accelerometry. Indicators of adiposity included body mass index, waist circumference, and the sum of subscapular and triceps skinfold thicknesses. Statistical analyses were performed using multilevel regression and isotemporal substitution models adjusted for confounders. Effect modification by ethnicity was examined.
There was no evidence for effect modification by ethnicity (P interaction ≥ 0.13). In the whole sample, the accumulated time spent above 3500 counts per minute (i.e., high light-intensity PA) was inversely associated with the sum of skinfolds (β = -0.60 mm, 95% confidence interval [CI] = -1.19 to -0.021, per 20 min·d), and the magnitude of association increased dose dependently with PA intensity (peaking for time spent >6000 counts per minute = -1.57 mm, 95% CI = -3.01 to -0.12, per 20 min·d). The substitution of 20 min·d of sedentary time with moderate-to-vigorous PA was associated with a lower sum of skinfolds (-0.77 mm, 95% CI = -1.46 to -0.084).
High light-intensity PA appears to be beneficial for body composition in young South Asian and White British children, but higher-intensity PA is more advantageous.
本研究旨在调查在一个以双种族（南亚裔和英国白人）为主的幼儿样本中，客观测量的身体活动（PA）和久坐时间与肥胖之间的关联。
样本包括333名年龄在11个月至5岁之间的儿童，他们提供了526次关于PA和身体成分的横断面观察数据。使用三轴加速度计估计总PA量（每分钟向量大小计数）、多个强度水平下的每日时间（活动强度>500、>1000、>1500、…、>6000次/分钟的累计时间）以及久坐时间（<820次/分钟）、轻度PA时间（820 - 3907次/分钟）和中度至剧烈PA时间（≥3908次/分钟）。肥胖指标包括体重指数、腰围以及肩胛下和肱三头肌皮褶厚度之和。使用多水平回归和针对混杂因素进行调整的等时替代模型进行统计分析。研究了种族的效应修正。
没有证据表明种族存在效应修正（P交互作用≥0.13）。在整个样本中，每分钟计数超过3500次（即高强度轻度PA）的累计时间与皮褶厚度之和呈负相关（β = -0.60毫米，95%置信区间[CI] = -1.19至 -0.021，每20分钟·天），且关联强度随PA强度呈剂量依赖性增加（在每分钟计数>6000次时达到峰值 = -1.57毫米，95% CI = -3.01至 -0.12，每20分钟·天）。用中度至剧烈PA替代20分钟·天的久坐时间与较低的皮褶厚度之和相关（-0.77毫米，95% CI = -1.46至 -0.084）。
高强度轻度PA似乎对南亚裔和英国白人幼儿的身体成分有益，但更高强度的PA更具优势。
