Cradock Angie L, Wiecha Jean L, Peterson Karen E, Sobol Arthur M, Colditz Graham A, Gortmaker Steven L
Department of Society, Human Development and Health, Harvard School of Public Health, Boston, MA 02115, USA.
Med Sci Sports Exerc. 2004 Mar;36(3):525-32. doi: 10.1249/01.mss.0000117112.76067.d3.
To examine significance of missing data and describe physical activity patterns using recall and accelerometer measures among youth in a nonlaboratory setting.
Fifty-four middle-school students wore TriTrac-R3D monitors (TTM) and completed an interviewer-prompted 24-h recall during two, 5-d monitoring sessions. We coded 2860 30-min recall intervals to a standard MET compendium. Complete TTM data were gathered for 43 students. Ordinal multinomial models tested for bias in TTM estimates of activity levels due to: 1) exclusion of subjects with incomplete TTM data, and 2) exclusion of intervals within days due to missing TTM data.
Students with complete monitor data had an average 12.5 +/- 0.9 monitored hours per day over 5.5 +/- 2.1 d. Compared with students with incomplete monitoring data, they reported similar proportions of recall 30-min intervals at sedentary (68% vs 69%), light (14% vs 15%), moderate (11% vs 10%), and vigorous (7% vs 6%) intensity levels (P = 0.63). The proportion of recall intervals (within days) with and without simultaneous monitoring data did not differ by activity intensity (P = 0.64) across sedentary (69% vs 67%), light (14% vs 12%), moderate (11% vs 10%), and vigorous (6% vs 9%) categories. Recalls overestimated percent time per day in moderate and vigorous activity relative to TTM (22.8% vs 8.9%, P < 0.0001). Boys reported higher percent of time than girls in vigorous activity (10.9% vs 3.9%, P < 0.05). Girls reported more time than boys (9.5% vs 6.4%, P < 0.05) in light activities. No significant sex differences were observed using TTM.
Missing TTM data did not bias estimates of activity levels. Self-reported activity measures overestimated moderate and vigorous activity relative to the TTM and varied by sex.
在非实验室环境中，研究青少年缺失数据的意义，并使用回忆法和加速度计测量来描述身体活动模式。
54名中学生佩戴TriTrac-R3D监测仪（TTM），并在两个为期5天的监测时段内完成由访谈者引导的24小时回忆。我们将2860个30分钟的回忆间隔编码为标准的代谢当量简编。为43名学生收集了完整的TTM数据。使用有序多项模型测试由于以下原因导致的TTM活动水平估计偏差：1）排除TTM数据不完整的受试者；2）由于TTM数据缺失而排除各天内的间隔。
拥有完整监测数据的学生在5.5±2.1天内平均每天有12.5±0.9小时的监测时间。与监测数据不完整的学生相比，他们报告的久坐（68%对69%）、轻度（14%对15%）、中度（11%对10%）和剧烈（7%对6%）强度水平的30分钟回忆间隔比例相似（P = 0.63）。在久坐（69%对67%）、轻度（14%对12%）、中度（11%对10%）和剧烈（6%对9%）类别中，有和没有同步监测数据的回忆间隔比例在不同活动强度下没有差异（P = 0.64）。与TTM相比，回忆法高估了每天中度和剧烈活动的时间百分比（22.8%对8.9%，P < 0.0001）。男孩报告的剧烈活动时间百分比高于女孩（10.9%对3.9%，P < 0.05）。女孩报告的轻度活动时间比男孩多（9.5%对6.4%，P < 0.05）。使用TTM未观察到显著的性别差异。
TTM数据缺失并未使活动水平估计产生偏差。相对于TTM，自我报告活动测量高估了中度和剧烈活动，且存在性别差异。
