School Food Environment and Child Well-Being

描述（由申请人提供）：打击儿童肥胖流行病的努力越来越集中在学校。这并不奇怪，因为多达40%的儿童每日能量摄入发生在学校，这表明学校的食物环境可能对他们的整体饮食和能量摄入产生很大影响。尽管这一政策的重点，但是，学校的食物环境对儿童的饮食和福祉的因果关系的影响还没有得到很好的理解，因为在解决潜在的内分泌与横截面数据的固有困难。在这项研究中，我们建议使用纵向数据和准实验方法来估计学校食品环境的一个重要方面的因果关系-具体来说，竞争性食品供应（以下简称CFA），定义为学校午餐和早餐计划以外的学校可供销售的食品和饮料-对儿童的饮食行为，体重和其他健康-和学校相关的结果。有竞争力的食品不需要满足联邦营养标准，但直接与营养竞争。 规范学校伙食。与学校餐相比，它们的营养价值较低-因此，通常被称为“垃圾食品”-但由于它们的味道，它们往往对儿童更具吸引力。学校提供这些食品可能会导致儿童从营养规范的校餐和从家里带来的膳食中摄取热量，转而食用竞争性食品，从而导致整体饮食质量的变化，进而导致体重和儿童福祉的变化。我们的研究有三个具体目标：1。描述ECLS-K样本中5年级和8年级竞争性食物的可用性，并确定预测其可用性的因素。2.估计CFA对饮食行为的影响，包括学校用餐参与，在学校购买垃圾食品，以及特定食物和饮料的总体消费。3.评估CFA对身体质量指数（BMI），超重和肥胖以及健康和学校相关结果的影响，如身体活动，学术和社会行为结果。这些分析将依赖于来自幼儿纵向研究-幼儿园队列（ECLSK）的数据，这是一个为期9年的全国代表性儿童队列小组。我们将主要研究五年级（n= 9，300）和八年级（n= 7，400）的结果，收集CFA和儿童饮食行为的信息。鉴于解决学校食品环境潜在内环境问题的复杂性，我们将采用几种成熟的计量经济学方法，包括增值模型，倾向得分加权，工具变量估计和儿童固定效应模型。我们的研究结果将对全国各州和学校系统至关重要，这些系统正在寻求为竞争性食品供应的决策提供信息。 公共卫生相关性：学校食品环境对儿童的总体饮食和能量摄入有很大影响;然而，由于解决学校食品环境潜在的内毒素问题存在固有的困难，其对儿童饮食和健康的因果影响尚未得到充分理解。我们的研究将提供全面和独特的证据，在儿童发展的两个关键点，为全国儿童样本的CFA可能的因果关系的影响。我们的研究结果将对全国各州和学校系统至关重要，这些系统正在寻求为竞争性食品供应的决策提供信息。

DESCRIPTION (provided by applicant): Efforts to combat the childhood obesity epidemic are increasingly focused on schools. This is not surprising given that as much as 40 percent of children's daily energy intake occurs at school, suggesting that the school food environment can have a large impact on their overall diet and energy intake. Despite this policy focus, however, the causal effects of the school food environment on children's diet and well-being are not yet well understood because of the inherent difficulties in addressing potential endogeneity with cross-sectional data. In this study, we propose to use longitudinal data and quasi-experimental methods to estimate the causal effect of one important aspect of the school food environment - specifically, competitive food availability (hereafter, CFA), defined as foods and beverages available for sale in schools outside of the school lunch and breakfast programs - on children's dietary behaviors, body weight and other health- and school-related outcomes. Competitive foods are not required to meet federal nutrition standards, but directly compete with nutritionally regulated school meals. They have lower nutritional value compared to school meals- therefore, commonly referred to as "junk foods" - but are often more attractive to children due to their taste. Their availability in schools might lead children to substitute calories away from nutritionally-regulated school meals and meals brought from home towards competitive foods, leading to changes in overall diet quality, and subsequently, body weight and child well-being. Our study has three specific aims: 1. Describe the availability of competitive foods in the ECLS-K sample during grades 5 and 8 and identify factors that predict their availability. 2. Estimate th effect of CFA on dietary behaviors including school meal participation, in-school junk food purchases, and overall consumption of specific foods and beverages. 3. Estimate the effect of CFA on body mass index (BMI), overweight and obesity as well as health- and school related outcomes such as physical activity, academics and social-behavioral outcomes. The analyses will rely on data from the Early Childhood Longitudinal Study - Kindergarten Cohort (ECLSK), a 9-year panel on a nationally-representative cohort of children. We will primarily examine outcomes from the 5th (n=9,300) and 8th (n=7,400) grade waves, when information on CFA and children's dietary behavior was collected. Given the complexities of addressing the potential endogeneity of school food environment, we will undertake several well-established econometric approaches including value-added models, propensity score weighting, instrumental variables estimation, and child fixed effects models. Our findings will be critical fo states and school systems across the nation that are seeking to inform decisions on competitive food availability. Public Health Relevance: The school food environment can have a large impact on children's overall diet and energy intake; however, its causal effects on children's diet and well-being are not yet well-understood because of the inherent difficulties in addressing potential endogeneity of the school food environment. Our study will provide comprehensive and unique evidence on the likely causal effects of CFA during two critical points in child development for a national sample of children. Our findings will be critical for states and school systems across the nation that are seeking to inform decisions on competitive food availability.