School Food Environment and Child Well-Being

描述(申请人提供)：抗击儿童肥胖症流行的努力越来越集中在学校。这并不令人惊讶，因为孩子们每天高达40%的能量摄入量发生在学校，这表明学校的食物环境可能会对他们的整体饮食和能量摄入量产生很大影响。然而，尽管有这一政策重点，但学校食物环境对儿童饮食和福祉的因果影响尚未得到很好的了解，因为利用横断面数据处理潜在的内生性存在内在困难。在这项研究中，我们建议使用纵向数据和准实验方法来评估学校食物环境的一个重要方面-具体地说，竞争性食物可用性(以下简称CFA)-对儿童饮食行为、体重和其他与健康和学校相关的结果的因果影响。竞争性食品不要求达到联邦营养标准，但在营养方面直接与之竞争 学校规定的膳食。与学校用餐相比，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，往往对孩子们更具吸引力。它们在学校的供应可能会导致儿童将卡路里从受营养管制的学校膳食和从家里带来的膳食中取代，转向竞争性食物，从而导致总体饮食质量的变化，并随后改变体重和儿童健康。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年级的竞争食品的可用性，并确定预测它们可用性的因素。2.评估CFA对饮食行为的影响，包括参与学校膳食、在学校购买垃圾食品，以及特定食品和饮料的总体消费。3.评估CFA对身体质量指数(BMI)、超重和肥胖的影响，以及与健康和学校相关的结果，如体力活动、学业和社会行为结果。分析将依赖于早期儿童纵向研究-幼儿园队列(ECLSK)的数据，这是一个为期9年的小组，研究对象是具有全国代表性的儿童队列。我们将主要检查5级(n=9,300)和8级(n=7,400)波的结果，当时收集了关于CFA和儿童饮食行为的信息。鉴于解决学校食物环境潜在内生性的复杂性，我们将采用几种成熟的计量经济学方法，包括增值模型、倾向分数加权、工具变量估计和儿童固定效应模型。我们的发现将对全国各州和学校系统至关重要，这些州和学校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：学校食物环境可能对儿童的总体饮食和能量摄入量有很大影响；然而，由于在解决学校食物环境潜在的内生性方面存在内在困难，其对儿童饮食和福祉的因果影响尚未得到很好的理解。我们的研究将为全国儿童样本提供全面和独特的证据，说明CFA在儿童发展的两个关键点可能产生的因果影响。我们的发现将对全国各州和学校系统至关重要，这些州和学校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.