Impacts of Later High School Start Times on Adolescent Weight and Weight-Related Behavior

 描述(由申请者提供)：尽管国家睡眠基金会建议青少年每晚睡眠时间为8.5至9.25小时，但超过一半的美国16岁青少年的睡眠时间通常少于7小时。“睡眠债”的后果远远不只是妨碍日常运作，因为它对身心健康的多个领域都有害。在 在肥胖症流行的背景下，睡眠不足正在成为导致超重和与体重增加相关行为的潜在的重要和新的风险因素。虽然屏幕时间、家庭作业期望和其他因素等多种因素可能会阻碍美国青少年的睡眠，但研究表明，与青少年生物学不同步的高中早期开始时间是青少年获得充足睡眠的最大障碍之一。当儿童进入青春期时，昼夜节律发生变化，褪黑激素在晚上晚些时候分泌，晚上11点前很难入睡。这种神经生物学的变化意味着，上早起高中(上午8：30之前)的青少年，即使是那些努力争取早点就寝的青少年，也将难以获得充足的睡眠。天然 实验清楚地表明，较晚的开学使青少年有更多的机会积累充足的睡眠，但不幸的是，86%的美国学校在早上8：30之前开始上课我们假设，较晚的开始时间，一种公认的有效的睡眠干预措施，可能会促进与体重相关的健康。鉴于青春期是为长期肥胖风险行为模式奠定基础的关键年龄，迫切需要了解由于干预和政策变化而导致的睡眠增加对肥胖的影响。目前，有一个独特的机会来研究以社区为基础的自然实验在学校开始时间政策修改。明尼阿波利斯-圣彼得堡明尼苏达州大都会地区学区保罗将于2016年秋季将高中的开学时间从早上7：30改为上午8：30。我们建议收集这一变化前后学生体重和相关风险的数据(通过调查、客观体重和身高测量以及睡眠活动记录仪)，并收集不会改变高中上午7：30开始时间的比较区的高中生的数据。这项研究具有时间敏感性，因为基线，必须在2015/16学年结束前收集政策前的措施。我们的具体目标是：1)确定推迟高中开学时间与客观测量的体重随时间变化的关系。2)确定学校开学时间与肥胖相关行为之间的关系。我们还有一个额外的探索性目标，通过与利益相关者的访谈，评估与实施较晚的高中开始时间相关的障碍和促进者。这项研究的产品将对公众健康产生影响，因为它们将澄清青少年睡眠和肥胖之间的因果关系，并为学校政策能否将不健康的体重增加降至最低提供证据。如果有效，推迟上学时间，一项可以在美国各地社区实施的政策，可能有助于防止年轻人超重。

 DESCRIPTION (provided by applicant): Although the National Sleep Foundation recommends 8.5 to 9.25 hours of sleep per night for adolescents, more than half of US 16-year-olds regularly get less than seven hours. "Sleep debt" has consequences that extend far beyond hampering day-to-day functioning as it is deleterious to multiple areas of physical and mental health. In the context of the obesity epidemic, which has had a far-reaching public health impact, sleep insufficiency is emerging as a potentially important and novel risk factor for the development of excess weight gain and weight gain-related behaviors. While a variety of forces such as screen time, homework expectations, and other factors can be implicated in stymying American teenagers' sleep, research has shown that early high school start times, which are asynchronous with adolescent biology, are one of the most significant obstacles to youth being able to net sufficient sleep. When children begin puberty, circadian rhythms shift such that melatonin is secreted later in the evening making it difficult to fall asleep before 11pm. This neurobiological change means that adolescents who attend "early-start" (prior to 8:30am) high schools, even those who strive for an early bedtime, will struggle to get sufficient sleep. Natural experiments have clearly shown that later school starts allow adolescents a greater opportunity to accumulate adequate sleep, but unfortunately 86% of US schools start before 8:30am. We hypothesize that later start times, an established effective sleep intervention, may promote weight-related health. Given that adolescence is a critical age that sets the stage for long-term obesity risk behavior patterns, there is an urgent need to understand the obesity-related implications of increased sleep as a result of intervention and policy changes. Presently there is a unique opportunity to study a community- based natural experiment in school start time policy modification. A Minneapolis-St. Paul, MN metro area school district, will be shifting the start tim of its high school from 7:30am to 8:30am in Fall 2016. We propose to collect data on student weight and related risks (via survey, objective weight and height measurement, and sleep actigraphy) before and after this change in this district and high school students in a comparison district which will not be altering its 7:30am high school start time. This research is time-sensitive as baseline, pre-policy measures must be collected before the end of the 2015/16 school year. Our specific aims are: 1) Determine how a shift to a later high school start time relates to objectively measured weight change over time. 2) Identify the relationship between school start times and obesity-related behaviors over time. We have an additional exploratory aim to assess barriers and facilitators associated with implementing later high school start times via stakeholder interviews. The products of this research will have public health impact because they will clarify causal connections between sleep and obesity among adolescents as well as provide evidence for whether a school policy can minimize unhealthy weight gain. If effective, later school start times, a policy deployable in communities across the US, could help prevent excess weight gain in youth.