Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
PLoS One. 2012;7(5):e36345. doi: 10.1371/journal.pone.0036345. Epub 2012 May 9.
Imprecise measurement of physical activity variables might attenuate estimates of the beneficial effects of activity on health-related outcomes. We aimed to compare the cardiometabolic risk factor dose-response relationships for physical activity and sedentary behaviour between accelerometer- and questionnaire-based activity measures.
Physical activity and sedentary behaviour were assessed in 317 adults by 7-day accelerometry and International Physical Activity Questionnaire (IPAQ). Fasting blood was taken to determine insulin, glucose, triglyceride and total, LDL and HDL cholesterol concentrations and homeostasis model-estimated insulin resistance (HOMA(IR)). Waist circumference, BMI, body fat percentage and blood pressure were also measured.
For both accelerometer-derived sedentary time (<100 counts.min(-1)) and IPAQ-reported sitting time significant positive (negative for HDL cholesterol) relationships were observed with all measured risk factors--i.e. increased sedentary behaviour was associated with increased risk (all p ≤ 0.01). However, for HOMA(IR) and insulin the regression coefficients were >50% lower for the IPAQ-reported compared to the accelerometer-derived measure (p<0.0001 for both interactions). The relationships for moderate-to-vigorous physical activity (MVPA) and risk factors were less strong than those observed for sedentary behaviours, but significant negative relationships were observed for both accelerometer and IPAQ MVPA measures with glucose, and insulin and HOMA(IR) values (all p<0.05). For accelerometer-derived MVPA only, additional negative relationships were seen with triglyceride, total cholesterol and LDL cholesterol concentrations, BMI, waist circumference and percentage body fat, and a positive relationship was evident with HDL cholesterol (p = 0.0002). Regression coefficients for HOMA(IR), insulin and triglyceride were 43-50% lower for the IPAQ-reported compared to the accelerometer-derived MVPA measure (all p≤0.01).
Using the IPAQ to determine sitting time and MVPA reveals some, but not all, relationships between these activity measures and metabolic and vascular disease risk factors. Using this self-report method to quantify activity can therefore underestimate the strength of some relationships with risk factors.
体力活动变量测量不精确，可能会削弱活动对健康相关结果的有益影响的估计。我们旨在比较基于加速度计和问卷的活动测量的体力活动和久坐行为的心血管代谢风险因素剂量反应关系。
通过 7 天加速度计和国际体力活动问卷（IPAQ）评估 317 名成年人的体力活动和久坐行为。抽取空腹血样以确定胰岛素、葡萄糖、甘油三酯和总胆固醇、LDL 胆固醇和 HDL 胆固醇浓度以及稳态模型估计的胰岛素抵抗（HOMA(IR)）。还测量了腰围、BMI、体脂百分比和血压。
对于加速度计衍生的久坐时间（<100 计数/分钟）和 IPAQ 报告的坐姿时间，所有测量的风险因素都观察到了显著的正相关（HDL 胆固醇为负相关），即增加久坐行为与增加风险相关（所有 p≤0.01）。然而，对于 HOMA(IR)和胰岛素，与加速度计衍生的测量值相比，IPAQ 报告的测量值的回归系数低 50%以上（两种交互作用均 p<0.0001）。中等到剧烈体力活动（MVPA）与风险因素的关系弱于观察到的久坐行为，但对于加速度计和 IPAQ 的 MVPA 测量，与葡萄糖、胰岛素和 HOMA(IR)值都观察到显著的负相关（均 p<0.05）。对于加速度计衍生的 MVPA，还观察到与甘油三酯、总胆固醇和 LDL 胆固醇浓度、BMI、腰围和体脂百分比呈负相关，与 HDL 胆固醇呈正相关（p=0.0002）。与加速度计衍生的 MVPA 相比，IPAQ 报告的 MVPA 的 HOMA(IR)、胰岛素和甘油三酯的回归系数低 43-50%（均 p≤0.01）。
使用 IPAQ 确定坐姿时间和 MVPA 揭示了这些活动测量与代谢和血管疾病风险因素之间的一些关系，但并非全部。因此，使用这种自我报告方法来量化活动可能会低估与某些风险因素的关系的强度。
