Hamer Mark, Chastin Sebastien, Viner Russell M, Stamatakis Emmanuel
Institute of Sport Exercise & Health, Division of Surgery & Interventional Science, University College London, London, UK.
School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, UK.
Obesity (Silver Spring). 2021 Jan;29(1):220-225. doi: 10.1002/oby.23025. Epub 2020 Nov 1.
Intergenerational data on mother-offspring pairs were utilized in an instrumental variable analysis to examine the longitudinal association between BMI and sedentary behavior.
The sample included 3,864 mother-offspring pairs from the 1970 British Cohort Study. Height and weight were recorded in mothers (age 31 [5.4] years) and offspring (age 10 years) and repeated in offspring during adulthood. Offspring provided objective data on sedentary behavior (7-day thigh-worn activPAL) in adulthood at age 46 to 47 years.
Maternal BMI, the instrumental variable, was associated with offspring BMI at age 10 (change per kg/m , β = 0.11; 95% CI: 0.09 to 0.12), satisfying a key assumption of instrumental variable analyses. Offspring (change per kg/m , β = 0.010; 95% CI: -0.02 to 0.03 h/d) and maternal BMI (β = 0.017; 95% CI: 0.001 to 0.03 h/d) was related to offspring sedentary time, suggestive of a causal impact of BMI on sedentary behavior (two-stage least squares analysis, β = 0.18 [SE 0.08], P = 0.015). For moderate-vigorous physical activity, there were associations with offspring BMI (β = -0.010; 95% CI: -0.017 to -0.004) and maternal BMI (β = -0.007; 95% CI: -0.010 to -0.003), with evidence for causality (two-stage least squares analysis, β = -0.060 [SE 0.02], P = 0.001).
There is strong evidence for a causal pathway linking childhood obesity to greater sedentary behavior.
利用母婴对的代际数据进行工具变量分析，以检验体重指数（BMI）与久坐行为之间的纵向关联。
样本包括来自1970年英国队列研究的3864对母婴。记录了母亲（年龄31[5.4]岁）和后代（年龄10岁）的身高和体重，并在后代成年期重复测量。后代在46至47岁成年期提供了关于久坐行为的客观数据（7天佩戴在大腿上的activPAL）。
作为工具变量的母亲BMI与后代10岁时的BMI相关（每kg/m变化，β = 0.11；95%可信区间：0.09至0.12），满足工具变量分析的一个关键假设。后代（每kg/m变化，β = 0.010；95%可信区间：-0.02至0.03小时/天）和母亲BMI（β = 0.017；95%可信区间：0.001至0.03小时/天）与后代久坐时间相关，提示BMI对久坐行为有因果影响（两阶段最小二乘法分析，β = 0.18[标准误0.08]，P = 0.015）。对于中等强度至剧烈强度的身体活动，与后代BMI（β = -0.010；95%可信区间：-0.017至-0.004）和母亲BMI（β = -0.007；95%可信区间：-0.010至-0.003）相关，有因果关系的证据（两阶段最小二乘法分析，β = -0.060[标准误0.02]，P = 0.001）。
有强有力的证据表明存在一条将儿童肥胖与更多久坐行为联系起来的因果途径。
