Sensitivity of the Circadian Clock to Light in Early Childhood

幼儿时期昼夜节律钟对光的敏感性

• 批准号: 9239487
• 负责人: MONIQUE K LEBOURGEOIS
• 金额: $ 61.48万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-03-18 至 2022-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9239487
• 关键词: Acute; Address; Adolescence; Adult; Affect; Age; Behavioral; Child; Chronic; Circadian Rhythms; Crystallization; Data; Development; Diabetes Mellitus; Elderly; Electronics; Environment; Foundations; Health; Home environment; Human; Individual Differences; Intervention; Knowledge; Life; Light; Link; Literature; Logistic Models; Low income; Measures; Medical; Melatonin; Mood Disorders; Nursery Schools; Obesity; Ophthalmology; Outcome; Pathway interactions; Pattern; Phase; Phenotype; Physiology; Protocols documentation; Publishing; Pupil; Randomized; Recommendation; Research; Research Design; Research Project Grants; Resistance; Risk; Risk Factors; Salivary; Schedule; School-Age Population; Sleep; Sleep Disorders; System; Time; base; circadian pacemaker; cognitive function; design; early childhood; innovation; intervention program; lens; light effects; light intensity; light transmission; minority children; novel; prevent; resilience; response; sleep onset; sleep regulation; transmission process

PROJECT SUMMARY Although late sleep timing is emerging as a significant risk factor for chronic health conditions, a gap exists in understanding the mechanisms underlying the development of a delayed sleep phenotype. This is particularly true for early childhood, a sensitive period in the maturation of sleep regulation and a time when poor sleep patterns first emerge. Late sleep timing and behavioral sleep problems are prevalent in ~25% of preschoolers. Central to the proposed research are our published data indicating that evening sleep problems and delayed sleep timing are linked to a later timing of the circadian system. Light is the primary zeitgeber of the circadian clock, and even low intensities of light can suppress melatonin levels and delay or advance circadian timing. For several reasons, we believe that light may be significant for determining sleep and circadian timing in early childhood: (1) the melatonin suppressing effects of evening light in school-age children are ~2x that of adults; (2) children are proposed to be more sensitive to light than adults based upon differences in ophthalmological features; (3) the enhanced transmission rate of the crystal lens in developing humans is prominent in the short wavelength of light, which is emitted from light-emitting diode electronic devices; and (4) media use has almost tripled in preschoolers in the past years and is associated with delayed sleep timing and evening sleep problems. This research will build upon our pilot data showing that 1 h of bright light before bedtime leads to high (~90%) suppression of melatonin in preschoolers. We will examine the sensitivity of the circadian clock to varying intensities of morning and evening light in preschool age children. We will obtain key data on light as a pathway by which delayed sleep timing is promoted and early sleep timing is protected in early childhood. Children (ages 3.0-4.9 years) follow a stable sleep schedule (7 days) and then enter an in-home dim-light environment (3 days), where they are exposed to a single illuminance of light for 3 h, ranging from 1 lux to 10,000 lux in either the morning (Advance condition; n=45) or the evening (Delay condition; n=45) starting 1.5 h before scheduled bedtime or wake time. Salivary melatonin onset assessments are performed using our established protocol at Baseline and the day following light exposure. In Aim 1, we will examine the sensitivity of the circadian clock to evening light, and in Aim 2, we will examine the sensitivity of the circadian clock to morning light. We hypothesize that evening/morning light exposure will induce circadian phase shifts and acute melatonin suppression in a non-linear intensity-dependent manner. This research is innovative, timely, and we expect that results will have a high payoff by addressing fundamental knowledge gaps relevant to modifiable targets (i.e., light, circadian timing) that may promote risk for or resilience to late sleep timing. Our data will make important contributions to the field by establishing the minimum and saturating light levels needed to produce circadian phase shifts, which are critical for making recommendations about light exposure and developing countermeasures for late sleep timing in early childhood.

项目摘要 尽管晚期的睡眠时间正在成为慢性健康状况的重要危险因素，但存在差距 了解延迟睡眠表型发展的机制。尤其是 在童年时期是正确的，睡眠调节成熟的敏感时期和睡眠不良的时期 模式首先出现。在约25％的学龄前儿童中，晚期睡眠时间和行为睡眠问题普遍存在。 拟议研究的中心是我们已发布的数据，表明晚上的睡眠问题并延迟 睡眠时间与昼夜节律系统的后期时间有关。光是昼夜节律的主要Zeitgeber 时钟，甚至低强度的光都会抑制褪黑激素水平，并延迟或提高昼夜节律时间。 由于几个原因，我们认为光对于确定睡眠和昼夜节律时间可能很重要 童年：（1）夜生活在学龄儿童中的褪黑激素抑制作用约为成年人的2倍； （2）根据眼科的差异，认为儿童比成人更敏感。 特征; （3）在短期内，晶体晶状体的传播速率提高了 光的波长是由发光二极管电子设备发出的； （4）媒体使用几乎有 在过去的几年中，学龄前儿童增加了两倍，与延迟的睡眠时间和晚上睡眠有关 问题。这项研究将基于我们的试点数据，表明睡前1小时的光线会导致 学龄前儿童中褪黑激素的抑制高（〜90％）。我们将检查昼夜节律对 学龄前儿童的早晨和晚上的不同强度。我们将在光线下获得关键数据 促进睡眠时间延迟的途径，并在幼儿时期受到早期睡眠时间的保护。 儿童（3.0-4.9岁）遵循稳定的睡眠时间表（7天），然后进入家庭昏暗的光线 环境（3天），在其中暴露于单一的照明范围3小时，范围从1勒克斯到 上午（预先条件; n = 45）或晚上（延迟条件; n = 45）开始1.5 h预定的就寝时间或唤醒时间。使用我们的 在基线和光线暴露后的第二天建立的方案。在AIM 1中，我们将检查灵敏度 在昼夜灯光下，在AIM 2中，我们将检查昼夜节律对 早晨的光。我们假设那天晚上/早晨的光线暴露将引起昼夜节律的偏移和 以非线性强度依赖性方式抑制急性褪黑激素。这项研究是创新的，及时的 我们预计结果将通过解决与 可修改的目标（即光线，昼夜节律）可能会促进迟到时间的风险或弹性。我们的 数据将通过建立最小和饱和的光水平为现场做出重要贡献 产生昼夜节相距需要，这对于提出有关轻型暴露的建议至关重要 并在童年时期为晚期睡眠时机开发对策。