Circadian rhythm phase shifts and endogenous free-running circadian period differ between African-Americans and European-Americans

Eastman, Charmane I.; Suh, Christina; Tomaka, Victoria A.; Crowley, Stephanie J.

doi:10.1038/srep08381

Cited by 82 publications

(96 citation statements)

References 56 publications

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“…It is also possible that differences related to genetic ancestry may relate to circadian period on one hand and to sleep homeostasis in the other in ways which counteract each other in terms of the MEQ. Thus, the fact that we found no significant association between MEQ and African ancestry does not in itself contradict the findings of Eastman and colleagues (Eastman, Suh et al, 2015), which were based on physiological measures related to circadian period, but not sleep homeostasis. It is not inconceivable that adaptation to different latitudes could involve differences in circadian period.…”

Section: Discussioncontrasting

confidence: 56%

“…Indeed, differences in parameters of the circadian system were observed in the only available report of this kind, a small study comparing African-Americans and EuropeanAmericans, where the former displayed a shorter average circadian period and smaller phase shifts (Eastman, Suh et al, 2015). The same study used ancestrally informative markers (AIMs) to assess degree of genetic admixture.…”

Section: Introductionmentioning

confidence: 99%

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Amerindian (but not African or European) ancestry is significantly associated with diurnal preference within an admixed Brazilian population

Egan

Santos

Beijamini

et al. 2017

Chronobiology International

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Significant questions remain unanswered regarding the genetic versus environmental contributions to racial/ethnic differences in sleep and circadian rhythms. We addressed this question by investigating the association between diurnal preference, using the Morningness-Eveningness questionnaire (MEQ), and genetic ancestry within the Baependi Heart Study cohort, a highly admixed Brazilian population based in a rural town. Analysis was performed using measures of ancestry, using the Admixture program, and MEQ from 1,453 individuals. We found an association between the degree of Amerindian (but not European of African) ancestry and morningness, equating to 0.16 units for each additional percent of Amerindian ancestry, after adjustment for age, sex, education, and residential zone. To our knowledge, this is the first published report identifying an association between genetic ancestry and MEQ, and above all, the first one based on ancestral contributions within individuals living in the same community. This previously unknown ancestral dimension of diurnal preference suggests a stratification between racial/ethnic groups in an as yet unknown number of genetic polymorphisms.

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Section: Discussioncontrasting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Amerindian (but not African or European) ancestry is significantly associated with diurnal preference within an admixed Brazilian population

Egan

Santos

Beijamini

et al. 2017

Chronobiology International

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“…The earlier sleep phase is consistent with the shorter circadian period observed in women [71, 72]. Interestingly, there appears to be a sex-by-race interaction, such that the circadian period is shorter in women relative to men in European-Americans, but longer in women in African-Americans [73]. …”

Section: Sex Differences In Circadian Timing Systemsupporting

confidence: 62%

Neuroendocrine underpinnings of sex differences in circadian timing systems

Yan

Silver

2016

The Journal of Steroid Biochemistry and Molecular Biology

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There are compelling reasons to study the role of steroids and sex differences in the circadian timing system. A solid history of research demonstrates the ubiquity of circadian changes that impact virtually all behavioral and biological responses. Furthermore, steroid hormones can modulate every attribute of circadian responses including the period, amplitude and phase. Finally, desynchronization of circadian rhythmicity, and either enhancing or damping amplitude of various circadian responses can produce different effects in the sexes. Studies of the neuroendocrine underpinnings of circadian timing systems and underlying sex differences have paralleled the overall development of the field as a whole. Early experimental studies established the ubiquity of circadian rhythms by cataloging daily and seasonal changes in whole organism responses. The next generation of experiments demonstrated that daily changes are not a result of environmental synchronizing cues, and are internally orchestrated, and that these differ in the sexes. This work was followed by the revelation of molecular circadian rhythms within individual cells. At present, there is a proliferation of work on the consequences of these daily oscillations in health and in disease, and awareness that these may differ in the sexes. In the present discourse we describe the paradigms used to examine circadian oscillation, to characterize how these internal timing signals are synchronized to local environmental conditions, and how hormones of gonadal and/or adrenal origin modulate circadian responses. Evidence pointing to endocrinologically and genetically mediated sex differences in circadian timing systems can be seen at many levels of the neuroendocrine and endocrine systems, from the cell, the gland and organ, and to whole animal behavior, including sleep/wake or rest/activity cycles, responses to external stimuli, and responses to drugs. We review evidence indicating that the analysis of the circadian timing system is amenable to experimental analysis at many levels of the neuraxis, and on several different time scales, rendering it especially useful for the exploration of mechanisms associated with sex differences.

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“…Another confounding factor may be the admixture of European ancestry with African ancestry in the African-American population. Not only is the United States (Chicago) the northernmost location in this study, but it is also a country where Blacks have approximately 15% European ancestry, which is relevant because Europeans have a slightly longer circadian period than Africans do and, consequently, are expected to have later acrophases (Eastman et al, 2015). …”

Section: Discussionmentioning

confidence: 99%

Daily activity patterns of 2316 men and women from five countries differing in socioeconomic development

Sani

Refinetti

Jean-Louis

et al. 2015

Chronobiology International

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Daily rhythmicity in the locomotor activity of laboratory animals has been studied in great detail for many decades, but the daily pattern of locomotor activity has not received as much attention in humans. We collected waist-worn accelerometer data from more than 2,000 individuals from five countries differing in socioeconomic development and conducted a detailed analysis of human locomotor activity. Body mass index was computed from height and weight. Individual activity records lasting 7 days were subjected to cosinor analysis to determine the parameters of the daily activity rhythm: mesor (mean level), amplitude (half the range of excursion), acrophase (time of the peak), and robustness (rhythm strength). The activity records of all individual participants exhibited statistically significant 24-hour rhythmicity, with activity increasing noticeably a few hours after sunrise and dropping off around the time of sunset, with a peak at 1:42 pm on average. The acrophase of the daily rhythm was comparable in men and women in each country but varied by as much as 3 h from country to country. Quantification of the socioeconomic stages of the five countries yielded suggestive evidence that more developed countries have more obese residents, who are less active, and who are active later in the day than residents from less developed countries. These results provide a detailed characterization of the daily activity pattern of individual human beings and reveal similarities and differences among people from five countries differing in socioeconomic development.

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Circadian rhythm phase shifts and endogenous free-running circadian period differ between African-Americans and European-Americans

Cited by 82 publications

References 56 publications

Amerindian (but not African or European) ancestry is significantly associated with diurnal preference within an admixed Brazilian population

Amerindian (but not African or European) ancestry is significantly associated with diurnal preference within an admixed Brazilian population

Neuroendocrine underpinnings of sex differences in circadian timing systems

Daily activity patterns of 2316 men and women from five countries differing in socioeconomic development

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