Department of Kinesiology, University of Wisconsin-Madison, Madison, WI 53706-1121, USA.
Med Sci Sports Exerc. 2013 Aug;45(8):1493-500. doi: 10.1249/MSS.0b013e318288a1e5.
The purpose of this study was to examine the association between sedentary behavior (SB), cardiometabolic risk factors, and self-reported physical function by level of moderate-vigorous physical activity (MVPA).
Cross-sectional analysis was completed on 1914 older adults age ≥ 65 yr from the 2003-2006 U.S. National Health and Nutrition Examination Survey. MVPA and SB were derived from ActiGraph accelerometers worn for 1 wk. MVPA was categorized as sufficient to meet the current U.S. guidelines (≥ 150 min · wk(-1)) or not; SB was split into quartiles. Various biomarkers were examined in laboratory analyses and physical exams, and the number of functional limitations was self-reported. Statistical interaction between SB and MVPA on the biomarker associations was the primary analysis, followed by an examination of their independent associations with relevant covariate adjustment.
Average SB was 9.4 ± 2.3 h · d(-1) (mean ± SD), and approximately 35% were classified as sufficiently active. Overall, no significant meaningful statistical interactions were found between SB and MVPA for any of the outcomes; however, strong independent positive associations were found between SB and weight (P < 0.01), body mass index (P < 0.01), waist circumference (P < 0.01), C-reactive protein (P < 0.01), plasma glucose (P = 0.04), and number of functional limitations (P < 0.01) after adjustment for MVPA. Similarly, MVPA was negatively associated with weight (P = 0.01), body mass index (P < 0.01), waist circumference (P < 0.01), diastolic blood pressure (P = 0.04), C-reactive protein (P < 0.01), and number of functional limitations (P < 0.01) after adjustment for SB.
The results suggest that sufficient MVPA did not ameliorate the negative associations between SB and cardiometabolic risk factors or functional limitations in the current sample and that there was independence on a multiplicative scale in their associations with the outcomes examined. Thus, older adults may benefit from the joint prescription to accumulate adequate MVPA and avoid prolonged sitting.
本研究旨在探讨久坐行为（SB）与心血管代谢风险因素以及自我报告的身体功能之间的关系，分析的依据是中高强度体力活动（MVPA）的水平。
本横断面分析使用了 2003-2006 年美国国家健康和营养调查（NHANES）中 1914 名年龄≥65 岁的老年人的数据。MVPA 和 SB 是通过佩戴 ActiGraph 加速度计 1 周得出的。MVPA 被分为足够满足当前美国指南（≥150 分钟·wk（-1））和不足两类；SB 则被分为四分位数。各种生物标志物在实验室分析和体检中进行了检查，功能障碍的数量则通过自我报告。主要分析了 SB 和 MVPA 对生物标志物关联的统计交互作用，然后检查了它们与相关协变量调整后的独立关联。
平均 SB 为 9.4±2.3 小时·天（平均值±标准差），约 35%的人被归类为活动充足。总体而言，在任何结果中，都没有发现 SB 和 MVPA 之间存在显著的有意义的统计学交互作用；然而，在调整 MVPA 后，SB 与体重（P<0.01）、体重指数（P<0.01）、腰围（P<0.01）、C 反应蛋白（P<0.01）、血浆葡萄糖（P=0.04）和功能障碍数量（P<0.01）之间存在强烈的独立正相关关系。同样，MVPA 与体重（P=0.01）、体重指数（P<0.01）、腰围（P<0.01）、舒张压（P=0.04）、C 反应蛋白（P<0.01）和功能障碍数量（P<0.01）之间也存在负相关关系，这些关系在调整 SB 后仍然存在。
结果表明，在当前样本中，足够的 MVPA 并不能改善 SB 与心血管代谢风险因素或功能障碍之间的负相关关系，而且它们与所检查的结果之间存在乘法尺度上的独立性。因此，老年人可能受益于联合处方，即积累足够的 MVPA 和避免长时间久坐。
