Evaluation of California's SB19 Pupil Nutrition Act

描述（由申请人提供）： 为了应对日益增长的儿童肥胖问题，加州最近签署了一项法律，对加州中小学的营养环境进行了雄心勃勃的改革。SB 19，即《2001年学生营养、健康和成绩法》，定于2004年开始实施。除其他事项外，这项法案将有效地禁止加州所有小学在上学期间销售苏打水、糖果和其他能量密集型零食，并限制中学的苏打水销售。它还将通过学区政策的变化促进增加体育活动和增加水果和蔬菜的消费。科学家们有机会在2003日历年对SB 19进行随机对照研究，以评估SB 19减少儿童超重的潜力。在2004年颁布第19号标准之后，在二年级期间继续对学习学校进行监测将带来进一步的好处。主要研究结果是身体成分（性别特定的生长图表调整BMI）和有氧能力（一英里跑步时间）。加州的大多数学校已经依法每年收集这些措施。过程措施将包括学校一级和个别学生一级的数据。学校数据将包括对竞争性食品的分析以及记录营养和体育活动政策的变化。个人数据将来自健康儿童调查，这是一项由大多数学校完成的两年一度的调查，其中包括关于饮食、体育活动和体重控制实践的BRFS类型项目。还将评估血压。四个混合种族学区将被随机分配到SB 19或通常的做法。根据州法律，BMI和身体健康的基线指标已经被收集。将收集2520名小学生和2500名中学生的基线和12个月随访BMI和体能指标。分析将包括多水平建模以及线性混合模型分析，并将考虑组内相关性。在全州范围内收集的数据将专门在学校一级进行比较，以评估通过SB19所代表的自然实验的影响。

DESCRIPTION (provided by applicant): In response to growing alarm over the rise of obesity among its children, California recently signed into law ambitious changes in the nutrition environment of California's elementary and middle schools. SB 19, the Pupil Nutrition, Health and Achievement Act of 2001, is scheduled to begin in 2004. Among other things, this act would effectively ban the sale of sodas, candy and other energy dense snacks during the school day in all California elementary schools and limit soda sales in middle schools. It would also promote increased physical activity and increased consumption of fruits and vegetables via school district policy changes. Scientists have a window of opportunity to conduct a randomized, controlled study of SB 19 during calendar year 2003 to assess SB 19's potential for reducing child overweight. Further benefit will result from continuing surveillance of study schools during Year 2, following enactment of SB 19 in 2004. Primary study outcomes are body composition (sex-specific growth-chart adjusted BMI) and aerobic capacity (one-mile run time). These measures are already collected annually by law at most California schools. Process measures will include school level and individual student level data. School data will include analysis of competitive foods and documented changes in nutrition and physical activity policies. Individual data will come from the Healthy Kids Survey, a biennial survey completed by most schools that includes BRFS-type items on diet, physical activity and weight control practices. Blood pressure will also be assessed. Four mixed ethnicity school districts will be randomized to SB 19 or usual practices. Baseline measures of BMI and physical fitness will have already been collected, by state law. Baseline and 12-month follow-up BMI and physical fitness measures will be collected from 2520 primary and 2500 middle school students. Analyses will include multi-level modeling as well as linear mixed model analyses and will take into account intraclass correlation. Data collected statewide exclusively at the school level will be compared to the multi-level study data in order to assess the impact of the natural experiment represented by the adoption of SB19.