Supplementary Information Files for: Is the positive relationship of infant weight gain with adolescent adiposity attenuated by moderate-to-vigorous physical activity in childhood?

Supplementary Information Files for: Is the positive relationship of infant weight gain with adolescent adiposity attenuated by moderate-to-vigoroObjectiveRapid infant weight gain is a key risk factor for pediatric obesity, yet there is very little evidence on how healthy behaviours in childhood might modify this association. We aimed to examine how the association of infant weight gain with adolescent adiposity might be attenuated by moderate-to-vigorous physical activity (MVPA) in childhood.MethodsThe sample comprised 4,666 children in the UK Millennium Cohort Study. The two outcomes were BMI Z-score and % fat at 14 years. Sex-stratified regression models were developed testing for interactions between infant weight Z-score gain between 0-3 years (continuous or categorical) and MVPA at 7 years (continuous or binary). Models were sequentially adjusted for basic covariates, socioeconomic variables, and parental BMI levels.ResultsEffect modification was observed in boys but not girls and, among boys, was stronger for % fat than BMI. In a fully adjusted model for boys, the association between infant weight Z-score gain and adolescent % fat was 1.883 (1.444, 2.322) if MVPA < 60 mins/day and 1.305 (0.920, 1.689) if MVPA ≥ 60 mins/day; the difference between these two estimates being -0.578 (-1.070, -0.087). Similarly, % fat was 2.981 (1.596, 4.367) units higher among boys who demonstrated rapid infant weight gain (+0.67 to +1.34 Z-score) compared to normal weight gain (-0.67 to +0.67 Z-scores), but having MVPA ≥ 60 mins/day reduced this effect size by -2.259 (-3.989, -0.535) units.ConclusionsIn boys, approximately 75% of the excess % fat at 14 years associated with rapid infant weight gain was attenuated by meeting the MVPA guideline. In boys known to have demonstrated rapid infant weight gain, increasing childhood MVPA levels, with the target of ≥60 mins/day, might therefore go a long way to towards offsetting their increased risk for adolescent obesity. The lack of effect modification in girls is likely due to lower MVPA levelsus physical activity in childhood?

本研究附随补充信息文件：婴儿期体重增长与青少年体脂堆积的正向关联是否会被儿童时期的中等至剧烈体力活动所缓解？
研究背景：婴儿期快速体重增长是儿童肥胖的关键风险因素，但目前关于儿童时期健康行为如何调控这一关联的证据十分有限。本研究旨在探讨儿童时期的中等至剧烈体力活动（moderate-to-vigorous physical activity, MVPA）是否会缓解婴儿期体重增长与青少年体脂堆积之间的关联。
研究方法：本研究样本取自英国千禧世代队列研究（UK Millennium Cohort Study）的4666名儿童。研究的两项结局指标为14岁时的BMI Z评分与体脂百分比。我们构建了按性别分层的回归模型，检验0~3岁婴儿期体重Z评分增长（连续型或分类变量）与7岁时中等至剧烈体力活动（连续型或二分类变量）之间的交互作用。模型依次针对基础协变量、社会经济状况变量以及父母BMI水平进行了调整。
研究结果：在男孩群体中观察到了效应修正现象，而女孩群体中未观察到此现象；且在男孩中，体脂百分比的效应修正强度高于BMI。针对男孩的完全调整模型显示，当中等至剧烈体力活动不足60分钟/天时，婴儿期体重Z评分增长与青少年体脂百分比之间的关联系数为1.883（95%置信区间：1.444, 2.322）；当中等至剧烈体力活动≥60分钟/天时，该关联系数为1.305（95%置信区间：0.920, 1.689），两者差值为-0.578（95%置信区间：-1.070, -0.087）。类似地，与婴儿期体重增长正常（Z评分变化范围-0.67~+0.67）的男孩相比，婴儿期快速体重增长（Z评分变化范围+0.67~+1.34）的男孩在14岁时的体脂百分比高出2.981（95%置信区间：1.596, 4.367）个单位；而当中等至剧烈体力活动≥60分钟/天时，这一效应量可降低2.259个单位（95%置信区间：0.535, 3.989）。
研究结论：在男孩群体中，与婴儿期快速体重增长相关的14岁时体脂过剩部分中，约有75%可通过达到中等至剧烈体力活动指南推荐量（≥60分钟/天）得到缓解。因此，对于已出现婴儿期快速体重增长的男孩，提升儿童时期的中等至剧烈体力活动水平至≥60分钟/天的目标，可在很大程度上抵消其青少年时期的肥胖风险。而女孩群体中未观察到效应修正现象，这可能与女孩的中等至剧烈体力活动水平较低有关。