Sensitivity of the Circadian Clock to the Spectrum of Evening Light in Early Childhood

项目摘要 儿童早期的晚睡时间和夜间睡眠问题会增加行为和行为不良的风险。 健康成果。光是昼夜节律系统的主要授时器，即使是少量的夜晚， 光可以抑制促睡眠激素褪黑激素的产生并延迟昼夜节律。的 光的光谱-不仅仅是强度-可能是决定睡眠的一个特别相关的因素， 儿童早期的昼夜节律有几个原因：（1）儿童对晚上的光线更敏感 由于眼科特征的差异，包括更大的瞳孔和更清晰的晶状体， 增加透光率;（2）幼儿在以下情况下表现出强烈的褪黑激素抑制（~90%） 晚上的强光照射;（3）在过去十年中，学龄前儿童的媒体使用急剧增加 并与晚睡时间和睡前阻力有关。这项研究的核心也是来自 年龄较大的儿童，青少年和成年人表明昼夜节律系统对短- 波长蓝光。然而，迄今为止，光谱在幼儿对夜晚的敏感性中的作用 光暴露及其对昼夜生理的不同影响是未知的。这是最主要的目的 F32研究项目。 在受试者内交叉设计中，参与者完成两次为期10天的方案。健康，良好的睡眠 3.0-4.9岁的儿童保持稳定的睡眠时间表7天，然后是3天的家庭昼夜节律 在昏暗的光线条件下进行评估。孩子们经历了两个平衡的实验 条件：高CCT（5000 K;蓝色富集）或低CCT（2700 K;红色富集）100勒克斯的光暴露， 在他们预定的就寝时间前1小时。在1-2周的“洗脱期”之后，用以下重复该方案： 剩余条件。我们将研究光谱对褪黑激素抑制的影响（目标1）， 昼夜节律相移（Aim 2）。昏暗光褪黑激素的发作是通过唾液评估，使用我们建立的 测定褪黑激素抑制%和昼夜节律相位延迟的方案。该提案的结果将 识别儿童夜间光照的可修改部分（例如光谱和时间），以帮助 父母对孩子的照明环境设定限制并做出健康的选择。结果很可能 具有很高的影响力，因为他们将提供行为改变建议，可以最大限度地减少负面影响， 夜间光照对儿童睡眠时间和质量的影响。 除了这些研究目标外，F32奖还将包括测量和分析的培训， 生理措施，先进的统计方法，赠款和手稿写作，传播 向公众公布调查结果和实验室管理人员。拟议的研究和培训将是一个重要步骤， 促进哈特斯坦博士转变为一名独立的科学家，其研究计划致力于进一步 研究照明环境对儿童睡眠、昼夜节律和发育的影响。

PROJECT SUMMARY Late sleep timing and evening sleep problems in early childhood increase the risk for poor behavioral and health outcomes. Light is the primary zeitgeber of the circadian system, and even small amounts of evening light can suppress production of the sleep-promoting hormone melatonin and delay circadian timing. The spectrum of light – not just the intensity – may be a particularly relevant factor for determining sleep and circadian timing in early childhood for several reasons: (1) children are more sensitive to evening light exposure than adults due to differences in ophthalmological features, including larger pupils and clearer lenses that increase light transmittance; (2) young children show robust melatonin suppression (~90%) following evening bright light exposure; and (3) media use in preschoolers has increased dramatically in the last decade and is associated with late sleep timing and bedtime resistance. Central to this research are also data from older children, adolescents, and adults indicating the circadian system shows high sensitivity to short- wavelength blue light. To date, however, the role of light spectrum in young children’s sensitivity to evening light exposure and its differential impact on circadian physiology is unknown. This is the primary purpose of this F32 research project. In a within-subjects crossover design, participants complete a 10-day protocol twice. Healthy, good sleeping children aged 3.0-4.9 years maintain a stable sleep schedule for 7 days, followed by a 3-day in-home circadian assessment performed in dim-light conditions. Children experience two counterbalanced experimental conditions: a high CCT (5000K; blue-enriched) or low CCT (2700K; red-enriched) light exposure of 100 lux for 1-h before their scheduled bedtime. Following a 1-2 week “washout period”, the protocol is repeated with the remaining condition. We will examine the impact of light spectrum on melatonin suppression (Aim 1) and circadian phase shift (Aim 2). Dim light melatonin onset is assessed through saliva using our established protocol to determine % melatonin suppression and circadian phase delay. The results of this proposal will identify modifiable components of children’s evening light exposure (e.g. light spectrum and timing) to help parents set limits and make healthy choices about their children’s lighting environment. Results are likely to have high impact, as they will provide behavioral change recommendations that can minimize the negative impacts of evening light exposure on children’s sleep duration and quality. In addition to these research aims, this F32 Award will incorporate training in the measurement and analysis of physiological measures, advanced statistical approaches, grant and manuscript writing, dissemination of findings to the public, and lab management. The research and training proposed will be an important step in facilitating Dr. Hartstein’s transition into an independent scientist with a research program committed to further examining the impacts of the lighting environment on children’s sleep, circadian rhythms, and development.