Paech Gemma M, Crowley Stephanie J, Fogg Louis F, Eastman Charmane I
Biological Rhythms Research Laboratory, Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois, United States of America.
PLoS One. 2017 Oct 23;12(10):e0186887. doi: 10.1371/journal.pone.0186887. eCollection 2017.
There are differences in sleep duration between Blacks/African-Americans and Whites/European-Americans. Recently, we found differences between these ancestry groups in the circadian system, such as circadian period and the magnitude of phase shifts. Here we document the role of ancestry on sleep and cognitive performance before and after a 9-h advance in the sleep/wake schedule similar to flying east or having a large advance in sleep times due to shiftwork, both of which produce extreme circadian misalignment. Non-Hispanic African and European-Americans (N = 20 and 17 respectively, aged 21-43 years) were scheduled to four baseline days each with 8 h time in bed based on their habitual sleep schedule. This sleep/wake schedule was then advanced 9 h earlier for three days. Sleep was monitored using actigraphy. During the last two baseline/aligned days and the first two advanced/misaligned days, beginning 2 h after waking, cognitive performance was measured every 3 h using the Automated Neuropsychological Assessment Metrics (ANAM) test battery. Mixed model ANOVAs assessed the effects of ancestry (African-American or European-American) and condition (baseline/aligned or advanced/misaligned) on sleep and cognitive performance. There was decreased sleep and impaired performance in both ancestry groups during the advanced/misaligned days compared to the baseline/aligned days. In addition, African-Americans obtained less sleep than European-Americans, especially on the first two days of circadian misalignment. Cognitive performance did not differ between African-Americans and European-Americans during baseline days. During the two advanced/misaligned days, however, African-Americans tended to perform slightly worse compared to European-Americans, particularly at times corresponding to the end of the baseline sleep episodes. Advancing the sleep/wake schedule, creating extreme circadian misalignment, had a greater impact on the sleep of African-Americans than European-Americans. Ancestry differences in sleep appear to be exacerbated when the sleep/wake schedule is advanced, which may have implications for individuals undertaking shiftwork and transmeridian travel.
黑人/非裔美国人和白人/欧裔美国人在睡眠时间上存在差异。最近，我们发现这些不同血统群体在昼夜节律系统方面存在差异，比如昼夜节律周期和相位偏移幅度。在此，我们记录了血统对睡眠及认知表现的影响，该影响发生在睡眠/清醒时间表提前9小时之后，这类似于向东飞行或因轮班工作导致睡眠时间大幅提前，这两种情况都会导致严重的昼夜节律失调。非西班牙裔非洲裔和欧裔美国人（分别为N = 20和17，年龄在21 - 43岁之间）根据他们的习惯睡眠时间，被安排进行为期四天的基线测试，每天卧床8小时。然后，将这个睡眠/清醒时间表提前9小时，持续三天。使用活动记录仪监测睡眠情况。在最后两天的基线/同步期以及前两天的提前/失调期，从醒来后2小时开始，每3小时使用自动神经心理评估指标（ANAM）测试组测量一次认知表现。混合模型方差分析评估了血统（非裔美国人或欧裔美国人）和状态（基线/同步或提前/失调）对睡眠和认知表现的影响。与基线/同步期相比，在提前/失调期，两个血统群体的睡眠时间均减少，表现受损。此外，非裔美国人的睡眠时间比欧裔美国人少，尤其是在昼夜节律失调的前两天。在基线期，非裔美国人和欧裔美国人的认知表现没有差异。然而，在两天的提前/失调期，与欧裔美国人相比，非裔美国人的表现往往略差，尤其是在与基线睡眠时段结束相对应的时间。提前睡眠/清醒时间表，造成严重的昼夜节律失调，对非裔美国人睡眠的影响比对欧裔美国人更大。当睡眠/清醒时间表提前时，睡眠方面的血统差异似乎会加剧，这可能对从事轮班工作和跨子午线旅行的人产生影响。
