Circadian rhythm of sleep and wakefulness : estimation of genetic influences with the method of twin study

在一个阶段的昼夜节律的个体差异进行了调查与适应轮班工作。在过去的十年中，昼夜节律睡眠障碍，这表明异常的昼夜相位和/或节律性，经常被报道。虽然生理节律的个体差异的重要性已被充分认识，但个体差异产生的原因仍不清楚，换句话说，遗传和环境对人类生理节律的影响尚未得到很好的研究。最近Linkowski和他的同事们研究了人体皮质醇分泌或心血管功能的昼夜变化。他们提出了遗传对人类昼夜节律的几个参数的影响，然而，睡眠和觉醒节律本身没有处理。本研究采用双生子研究的方法，对22对双生子（11对同卵双生子，11对异卵双生子）的睡眠和觉醒的昼夜节律参数进行了遗传学研究。 ...更多信息 双胞胎）参加了这项研究。通过问卷调查确定双胞胎的接合性。他们被要求每天记录他们的睡眠至少7天。他们还被要求填写关于他们的习惯性睡眠模式和觉醒行为的问卷以及Morningness and Eveningness Questionnaire（Horne and Ostberg，1976）。根据睡眠日志，作者将每15分钟的睡眠单位记为“1”，清醒单位记为“0”。用自相关函数估计其睡眠和觉醒周期的昼夜节律成分的幅度，同卵双生子和异卵双生子的平均就寝时间和起床时间的类内相关系数无差异，而用自相关函数估计的昼夜节律幅度以及被认为与核心体温相关的早晨和晚上评分的类内相关系数无差异。在同卵双胞胎中更高。后两个变量似乎是由基因决定的。少

Individual differences in a phase of circadian rhythm has been investigated in connection with adaptability for shift work. In the last decade, circadian rhythm sleep disorders, which shows abnormal circadian phase and/or rhythmicity, are frequently reported. Although the importance of the individual differences in circadian rhythms are well recognized, it is still unclear why the individual differences arise, in other words, genetic and environmental effects on the human circadian rhythm had not been well investigated. Recently Linkowski and co-workers investigated human circadian variations in cortisol secretion or in cardiovascular functions. They suggested genetic influences on several parameters of human circadian rhythm, however, sleep and wakefulness rhythm itself was not dealt with. This study aimed at evaluating genetical influences on several circadian rhythm parameters of sleep and wakefulness with the method of twin study.Twenty two pairs of twins (11 monozygotic and 11 diz … More ygotic twin pairs) participated in this study. Twin zygosity was determined by means of a questionnaire. They were asked to log their sleep on the daily basis for at least 7 days. They also asked to fill out the questionnaire concerning their habitual pattern of sleep and wake behavior and Morningness and Eveningness Questionnaire (Horne and Ostberg, 1976). Based on the sleep logs, the author scored each 15 min.unit of sleep as 'one' and that of wakefulness as 'zero.' Autocorrelation function was employed to estimate the amplitude of circadian component of their sleep and wakefulness cycle.Intra-class correlation coefficients for mean bedtime and rising time were not different between the monozygotic and dizygotic twin pairs, while that for circadian amplitude, estimated by autocorrelation function, and mornignness and eveningness score, which is considered to be correlated with core body temperature, were higher in the monozygotic twin pairs. The latter two variables seem to be genetically determined. Less