Early predictors and body composition changes associated with adiposity rebound

儿童超重和肥胖率正在上升，超重儿童患成人肥胖症的风险更高，因此患心脏病、中风和糖尿病的风险也更高。学龄前的几年可能提供机会，使儿童从肥胖的道路上转移，在不良的体育活动和营养习惯牢固建立之前。肥胖反弹是指儿童一生中（通常在5至6岁左右）体重指数（BMI）在学龄前体重指数稳步下降后开始增加的时间。早期肥胖反弹与以后生活中BMI增加有关。我们还不知道早期肥胖反弹是否导致了更高的BMI，或者它是否只是已经建立的行为和环境风险途径的早期迹象。我们需要更好地了解早期肥胖反弹的预测因素以及发生的变化，以确定肥胖反弹时的年龄是否是成人肥胖的可改变风险因素。这项研究将记录肥胖反弹的过程和时间，以及在此期间发生的体脂百分比和瘦体重的变化。我们还将确定早期肥胖反弹和6岁超重的风险和保护因素是否相同或不同。我们将对400多名儿童进行研究，这些儿童从出生起就收集了大量数据，包括妊娠期、出生体重和身长。在头两年的不同阶段，记录了它们的身高、体重、进食模式和发育情况。我们将测量BMI，并对这些4至6岁的儿童进行6次生物阻抗分析（BIA）。BIA提供了一种被儿童广泛接受的身体脂肪和瘦体重的测量方法。这将有助于确定不同年龄段BMI变化与与这些变化相关的脂肪与瘦肉质量比之间的关系。这项研究是第一个考虑肥胖反弹期间身体成分变化的研究。

Overweight and obesity rates are increasing in children, and overweight children have higher risk of adult obesity and therefore diseases including heart attack, stroke and diabetes. The preschool years may offer opportunities to divert children from the path to obesity, before poor physical activity and nutritional habits become firmly established. Adiposity rebound is the time in a child's life (usually around 5 to 6 years of age) when body mass index (BMI) begins to increase after a steady decline in BMI in the preschool years. Early adiposity rebound is associated with increased BMI in later life. We don't yet know whether the early adiposity rebound causes the higher BMI, or whether it is simply an early sign of an already-established pathway of behavioural and environmental risk. We need a much better understanding of predictors of early adiposity rebound and the changes that occur to determine if age at adiposity rebound is a modifiable risk factor for adult obesity. This study will document the process and timing of adiposity rebound and the changes in percent body fat and lean body mass that occur during that time. We will also determine whether risk and protective factors for early adiposity rebound and overweight at age 6 years are the same or different. We will study over 400 children on whom extensive data have been collected since birth, including period of gestation, birth weight and length. At various stages during their first two years of life, height, weight, feeding patterns and development were recorded. We will measure BMI and perform bioimpedance analysis (BIA) on these children six times between 4 and 6 years of age. BIA provides a measure of body fat and lean mass that is well accepted by children. This will help determine the relationship between changing BMI at different ages and the fat-to-lean mass ratios associated with those changes. This study is the first to consider body composition changes during adiposity rebound.