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Till Roenneberg - One of the best experts on this subject based on the ideXlab platform.
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Lower school performance in late Chronotypes: underlying factors and mechanisms.
Scientific Reports, 2017Co-Authors: Giulia Zerbini, Till Roenneberg, Thomas Kantermann, Vincent Van Der Vinne, Lana K. M. Otto, Wim P. Krijnen, Martha MerrowAbstract:Success at school determines future career opportunities. We described a time-of-day specific disparity in school performance between early and late Chronotypes. Several studies showed that students with a late Chronotype and short sleep duration obtain lower grades, suggesting that early school starting times handicap their performance. How Chronotype, sleep duration, and time of day impact school performance is not clear. At a Dutch high school, we collected 40,890 grades obtained in a variety of school subjects over an entire school year. We found that the strength of the effect of Chronotype on grades was similar to that of absenteeism, and that late Chronotypes were more often absent. The difference in grades between the earliest 20% and the latest 20% of Chronotypes corresponds to a drop from the 55th to 43rd percentile of grades. In academic subjects using mainly fluid cognition (scientific subjects), the correlation with grades and Chronotype was significant while subjects relying on crystallised intelligence (humanistic/linguistic) showed no correlation with Chronotype. Based on these and previous results, we can expand our earlier findings concerning exam times: students with a late Chronotype are at a disadvantage in exams on scientific subjects, and when they are examined early in the day.
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Chronotypes in the US - Influence of age and sex.
PLOS ONE, 2017Co-Authors: Dorothee Fischer, David A. Lombardi, Helen R. Marucci-wellman, Till RoennebergAbstract:An individual's Chronotype reflects how the circadian system embeds itself into the 24-h day with rhythms in physiology, cognition and behavior occurring accordingly earlier or later. In view of an increasing number of people working at unusual times and linked health and safety risks, the wide range in human Chronotypes may provide opportunities to allow people to work (and sleep) at times that are in synch with their circadian physiology. We aimed at estimating the distribution of Chronotypes in the US population by age and sex. Twelve years (2003-2014) of pooled diary data from the American Time Use Survey were used to calculate Chronotype based on mid-point of sleep on weekends (MSFWe, n = 53,689). We observed a near-normal distribution overall and within each age group. The distribution's mean value is systematically different with age, shifting later during adolescence, showing a peak in 'lateness' at ~19 years, and shifting earlier thereafter. Men are typically later Chronotypes than women before 40, but earlier types after 40. The greatest differences are observed between 15 and 25 for both sexes, equaling more than 50% of the total Chronotype difference across all age groups. The variability in Chronotype decreases with age, but is generally higher in males than females. This is the first study to estimate the distribution and prevalence of individual Chronotypes in the US population based on a large-scale, nationally representative sample. Our finding that adolescents are on average the latest Chronotypes supports delaying school start times to benefit their sleep and circadian alignment. The generally wide range in Chronotypes may provide opportunities for tailored work schedules by matching external and internal time, potentially decreasing long- and short-term health and safety risks.
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Chronotype and sleep duration: The influence of season of assessment
Chronobiology International, 2014Co-Authors: Karla V. Allebrandt, Thomas Kantermann, Maris Teder-laving, Annette Peters, Harry Campbell, Igor Rudan, James F. Wilson, Andres Metspalu, Till RoennebergAbstract:Little is known about human entrainment under natural conditions, partly due to the complexity of human behavior, torn between biological and social time and influenced by zeitgebers (light-dark cycles) that are progressively "polluted" (and thereby weakened) by artificial light. In addition, data about seasonal variations in sleep parameters are scarce. We, therefore, investigated seasonal variation in cross-sectional assessments of sleep/wake times of 9765 subjects from four European populations (EGCUT = Estonian Genome Centre, University of Tartu in Estonia; KORA = Cooperative Health Research in the Region of Augsburg in Germany; KORCULA = The Korcula study in Croatia; and ORCADES = The Orkney Complex Disease Study in Scotland). We identified time-of-year dependencies for the distribution of Chronotype (phase of entrainment assessed as the mid-sleep time point on free days adjusted for sleep deficit of workdays) in cohorts from Estonia (EGCUT) and Germany (KORA). Our results indicate that season (defined as daylight saving time - DST and standard zonetime periods - SZT) specifications of photoperiod influence the distribution of Chronotype (adjusted for age and sex). Second, in the largest investigated sample, from Estonia (EGCUT; N = 5878), we could detect that seasonal variation in weekly average sleep duration was dependent on individual Chronotype. Later Chronotypes in this cohort showed significant variation in their average sleep duration across the year, especially during DST (1 h advance in social time from the end of March to end of October), while earlier Chronotypes did not. Later Chronotypes not only slept less during the DST period but the average Chronotype of the population assessed during this period was earlier than during the SZT (local time for a respective time zone) period. More in detail, hierarchical multiple regression analyses showed that, beyond season of assessment (DST or SZT), social jetlag (SJl; the discrepancy between the mid sleep on free and work days - which varied with age and sex) contributed to a greater extent to the variation in sleep duration than Chronotype (after taking into account factors that are known to influence sleep duration, i.e. age, sex and body mass index). Variation in Chronotype was also dependent on age, sex, season of assessment and SJl (which is highly correlated with Chronotype - SJl was larger among later Chronotypes). In summary, subjective assessments of sleep/wake times are very reliable to assess internal time and sleep duration (e.g. reproducing sleep duration and timing tendencies related to age and sex across the investigated populations), but season of assessment should be regarded as a potential confounder. We identified in this study photoperiod (seasonal adaptation) and SJl as two main factors influencing seasonal variation in Chronotype and sleep duration. In conclusion, season of assessment, sex and age have an effect on epidemiological variation in sleep duration, Chronotype and SJl, and should be included in studies investigating associations between these phenotypes and health parameters, and on the development of optimal prevention strategies.
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Chronotype modulates sleep duration sleep quality and social jet lag in shift workers
Journal of Biological Rhythms, 2013Co-Authors: Celine Vetter, Myriam Juda, Till RoennebergAbstract:This study explores Chronotype-dependent tolerance to the demands of working morning, evening, and night shifts in terms of social jet lag, sleep duration, and sleep disturbance. A total of 238 shift-workers were Chronotyped with the Munich Chronotype Questionnaire for shift-workers (MCTQShift), which collects information about shift-dependent sleep duration and sleep timing. Additionally, 94 shift-workers also completed those items of the Sleep Questionnaire from the Standard Shift-Work Index (SSI) that assess sleep disturbances. Although all participants worked morning, evening, and night shifts, subsamples differed in rotation direction and speed. Sleep duration, social jet lag, and sleep disturbance were all significantly modulated by the interaction of Chronotype and shift (mixed-model ANOVAs). Earlier Chronotypes showed shortened sleep duration during night shifts, high social jet lag, as well as higher levels of sleep disturbance. A similar pattern was observed for later Chronotypes during early sh...
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Fibromyalgia syndrome and Chronotype: late Chronotypes are more affected.
Journal of Biological Rhythms, 2012Co-Authors: Thomas Kantermann, Till Roenneberg, Alice Theadom, Mark CropleyAbstract:Sleep has strong links to the symptomology of fibromyalgia syndrome (FMS), a diffuse musculoskeletal pain disorder. Information about the involvement of the circadian clock is, however, sparse. In this study, 1548 individuals with FMS completed an online survey containing questions on demographics, stimulant consumption, sleep quality, well-being and subjective pain, Chronotype (assessed by the Munich Chronotype Questionnaire, MCTQ), and FMS impact. Chronotype (expressed as the mid-sleep-point on free days, corrected for sleep deficit on workdays, MSF(sc)) significantly correlated with stress-ratings, so-called "memory failures in everyday life," fatigue, FMS impact, and depression but not with anxiety. When Chronotypes were categorized into 3 groups (early, intermediate, late), significant group differences were found for sum scores of perceived stress, memory failures in everyday life, fatigue, FMS impact, and depression but not anxiety, with late Chronotypes being more affected than early Chronotypes. Sleepiness ratings were highest in early Chronotypes. Challenges of sleep quality and subjective pain were significantly increased in both early and late Chronotypes. The results show that according to their reports, late Chronotypes are more affected by fibromyalgia.
Myriam Juda - One of the best experts on this subject based on the ideXlab platform.
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Chronotype modulates sleep duration sleep quality and social jet lag in shift workers
Journal of Biological Rhythms, 2013Co-Authors: Celine Vetter, Myriam Juda, Till RoennebergAbstract:This study explores Chronotype-dependent tolerance to the demands of working morning, evening, and night shifts in terms of social jet lag, sleep duration, and sleep disturbance. A total of 238 shift-workers were Chronotyped with the Munich Chronotype Questionnaire for shift-workers (MCTQShift), which collects information about shift-dependent sleep duration and sleep timing. Additionally, 94 shift-workers also completed those items of the Sleep Questionnaire from the Standard Shift-Work Index (SSI) that assess sleep disturbances. Although all participants worked morning, evening, and night shifts, subsamples differed in rotation direction and speed. Sleep duration, social jet lag, and sleep disturbance were all significantly modulated by the interaction of Chronotype and shift (mixed-model ANOVAs). Earlier Chronotypes showed shortened sleep duration during night shifts, high social jet lag, as well as higher levels of sleep disturbance. A similar pattern was observed for later Chronotypes during early sh...
Eva S Schernhammer - One of the best experts on this subject based on the ideXlab platform.
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Shift Work, Chronotype, and Melatonin Rhythm in Nurses
Cancer Epidemiology Biomarkers & Prevention, 2019Co-Authors: Pedram Razavi, Elizabeth E Devore, Archna Bajaj, Steven W Lockley, Mariana G Figueiro, Vincent Ricchiuti, Susan E Hankinson, W. James Gauderman, Walter C. Willett, Eva S SchernhammerAbstract:Background: Previous studies associated night-shift work with melatonin disruption, with mixed evidence regarding the modulating effects of Chronotype (i.e., diurnal preference). Methods: 130 active nurses (84 rotating-shift and 46 day-shift workers) in the Nurses9 Health Study II wore a head-mounted light meter and collected spontaneous urine voids over three days. 6-sulfatoxymelatonin (aMT6s), the major urinary metabolite of melatonin, was assessed. Results: Rotating-shift workers on night shifts had more light exposure and lower urinary melatonin levels during the night, and urinary melatonin rhythms with smaller peaks (14.83, 95% confidence interval [CI], 11.72-18.75 versus 11.81 ng/mg-creatinine/hour, 95%CI, 9.49-14.71) and later peak onset (4.10, 95%CI, 3.37-4.99 versus 5.71 hours, 95%CI, 4.76-6.85), compared to day-shift workers. Further, evening Chronotypes9 melatonin rhythms had later peak onset compared to morning types (4.90 hours, 95%CI, 3.94-6.09 versus 3.64 hours, 95%CI, 2.99-4.43). However, among day-shift workers, morning Chronotypes had melatonin rhythms with greater mean levels, larger peaks, and earlier peak onset compared to evening Chronotypes; patterns were similar comparing evening versus morning Chronotypes among rotating-shift workers on night shifts. The interaction of rotating-shift work and Chronotype was significant across all parameters (p
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prospective study of Chronotype and incident depression among middle and older aged women in the nurses health study ii
Journal of Psychiatric Research, 2018Co-Authors: Celine Vetter, Shunchiao Chang, Elizabeth E Devore, Florian Rohrer, Olivia I Okereke, Eva S SchernhammerAbstract:Abstract Background Prior cross-sectional studies have suggested that being a late Chronotype is associated with depression and depressive symptoms, but prospective data are lacking. Methods We examined the association between Chronotype and incident depression (defined as self-reported physician/clinician-diagnosed depression or antidepressant medication use) in 32,470 female participants of the Nurses’ Health Study II cohort who self-reported their Chronotype (early, intermediate or late) and were free of depression at baseline in 2009 (average age: 55 yrs). Women updated their depression status on biennial questionnaires in 2011 and 2013. We used multivariable (MV)-adjusted Cox proportional hazards models to estimate hazard ratios (HR) and 95% confidence intervals (95%CI) for incident depression across Chronotype categories (i.e., early, intermediate, and late Chronotypes). Results Across a follow-up period of 4 years, we observed 2,581 cases of incident depression in this cohort. Compared to intermediate Chronotypes, early Chronotypes had a modestly lower risk of depression after MV adjustment (MVHR = 0.88, 95%CI = 0.81–0.96), whereas late Chronotypes had a similar risk of 1.06 (95%CI = 0.93–1.20); the overall trend across Chronotype categories was statistically significant (ptrend Conclusions Our results suggest that Chronotype may influence the risk of depression in middle-to older-aged women. Additional studies are needed to confirm these findings and examine roles of both environmental and genetic factors to further our understanding of the role of Chronotype in the etiology of mood disorders.
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Chronotype and breast cancer risk in a cohort of us nurses
Chronobiology International, 2013Co-Authors: Cody Ramin, Elizabeth E Devore, Susan E Hankinson, Jeffrey Pierrepaul, Jeanne F Duffy, Eva S SchernhammerAbstract:The aim of this study was to examine the relation between Chronotype and breast cancer risk. We analyzed the association between Chronotype (definite morning type, probable morning type, probable evening type, definite evening type, or neither morning nor evening type) and breast cancer risk among 72 517 women in the Nurses’ Health Study II (NHS II). Chronotype was self-reported in 2009, and 1834 breast cancer cases were confirmed among participants between 1989 and 2007; a 2-yr lag period was imposed to account for possible circadian disruptions related to breast cancer diagnosis. Age- and multivariable-adjusted logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Participants who self-reported as neither morning nor evening type had a 27% increased risk of breast cancer (multivariable-adjusted OR = 1.27, 95% CI = 1.04–1.56), compared with definite morning types. None of the other Chronotypes were significantly associated with breast cancer risk (multivariable-ad...
Celine Vetter - One of the best experts on this subject based on the ideXlab platform.
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prospective study of Chronotype and incident depression among middle and older aged women in the nurses health study ii
Journal of Psychiatric Research, 2018Co-Authors: Celine Vetter, Shunchiao Chang, Elizabeth E Devore, Florian Rohrer, Olivia I Okereke, Eva S SchernhammerAbstract:Abstract Background Prior cross-sectional studies have suggested that being a late Chronotype is associated with depression and depressive symptoms, but prospective data are lacking. Methods We examined the association between Chronotype and incident depression (defined as self-reported physician/clinician-diagnosed depression or antidepressant medication use) in 32,470 female participants of the Nurses’ Health Study II cohort who self-reported their Chronotype (early, intermediate or late) and were free of depression at baseline in 2009 (average age: 55 yrs). Women updated their depression status on biennial questionnaires in 2011 and 2013. We used multivariable (MV)-adjusted Cox proportional hazards models to estimate hazard ratios (HR) and 95% confidence intervals (95%CI) for incident depression across Chronotype categories (i.e., early, intermediate, and late Chronotypes). Results Across a follow-up period of 4 years, we observed 2,581 cases of incident depression in this cohort. Compared to intermediate Chronotypes, early Chronotypes had a modestly lower risk of depression after MV adjustment (MVHR = 0.88, 95%CI = 0.81–0.96), whereas late Chronotypes had a similar risk of 1.06 (95%CI = 0.93–1.20); the overall trend across Chronotype categories was statistically significant (ptrend Conclusions Our results suggest that Chronotype may influence the risk of depression in middle-to older-aged women. Additional studies are needed to confirm these findings and examine roles of both environmental and genetic factors to further our understanding of the role of Chronotype in the etiology of mood disorders.
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Chronotype modulates sleep duration sleep quality and social jet lag in shift workers
Journal of Biological Rhythms, 2013Co-Authors: Celine Vetter, Myriam Juda, Till RoennebergAbstract:This study explores Chronotype-dependent tolerance to the demands of working morning, evening, and night shifts in terms of social jet lag, sleep duration, and sleep disturbance. A total of 238 shift-workers were Chronotyped with the Munich Chronotype Questionnaire for shift-workers (MCTQShift), which collects information about shift-dependent sleep duration and sleep timing. Additionally, 94 shift-workers also completed those items of the Sleep Questionnaire from the Standard Shift-Work Index (SSI) that assess sleep disturbances. Although all participants worked morning, evening, and night shifts, subsamples differed in rotation direction and speed. Sleep duration, social jet lag, and sleep disturbance were all significantly modulated by the interaction of Chronotype and shift (mixed-model ANOVAs). Earlier Chronotypes showed shortened sleep duration during night shifts, high social jet lag, as well as higher levels of sleep disturbance. A similar pattern was observed for later Chronotypes during early sh...
Mirja Quante - One of the best experts on this subject based on the ideXlab platform.
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Chronotype social jet lag and cardiometabolic risk factors in early adolescence
JAMA Pediatrics, 2019Co-Authors: Elizabeth Cespedes M Feliciano, Sheryl L Rifasshiman, Mirja Quante, Susan Redline, Emily Oken, Elsie M TaverasAbstract:Importance Inadequate sleep duration and quality increase the risk of obesity. Sleep timing, while less studied, is important in adolescents because increasing evening preferences (Chronotypes), early school start times, and irregular sleep schedules may cause circadian misalignment. Objective To investigate associations of Chronotype and social jet lag with adiposity and cardiometabolic risk in young adolescents. Design, Setting, and Participants Starting in 1999, Project Viva recruited pregnant women from eastern Massachusetts. Mother-child in-person visits occurred throughout childhood. From January 23, 2012, to October 16, 2016, 804 adolescents aged 12 to 17 years completed 5 days or more of wrist actigraphy, questionnaires, and anthropometric measurements. A cross-sectional analysis using these data was conducted from April 31, 2018, to May 1, 2019. Exposures Chronotype, measured via a continuous scale with higher scores indicating greater evening preferences, and social jet lag, measured as the continuous difference in actigraphy sleep midpoint in hours from midnight on weekends vs weekdays, with higher values representing more delayed sleep timing on weekends. Main Outcomes and Measures Adiposity, measured via anthropometry and dual-energy x-ray absorptiometry. For a subset of 479 adolescents with blood samples, cardiometabolic risk scores were computed as the mean of 5 sex- and cohort-specificzscores for waist circumference, systolic blood pressure, inversely scaled high-density lipoprotein cholesterol, and log-transformed triglycerides and homeostatic model of insulin resistance. Results Among the 804 adolescents in the study, 418 were girls and 386 were boys, with a mean (SD) age of 13.2 (0.9) years. In multivariable models adjusted for age, puberty, season, and sociodemographics, associations of Chronotype and social jet lag with adiposity varied by sex. For girls, greater evening preference was associated with a 0.58-cm (95% CI, 0.12-1.03 cm;P = .04 for interaction) higher waist circumference and 0.16 kg/m2(95% CI, 0.01-0.31 kg/m2;P = .03 for interaction) higher fat mass index as measured by dual-energy x-ray absorptiometry; each hour of social jet lag was associated with a 1.19-cm (95% CI, 0.04-2.35 cm;P = .21 for interaction) higher waist circumference and 0.45 kg/m2(95% CI, 0.09-0.82 kg/m2;P = .01 for interaction) higher fat mass index as measured by dual-energy x-ray absorptiometry. Associations of social jet lag and evening Chronotypes persisted for many measures of adiposity after adjustment for sleep duration and other lifestyle behaviors. By contrast, no associations were observed in boys. There were no associations with the cardiometabolic risk score for either sex, although statistical power was low for this outcome. Conclusions and Relevance Evening Chronotypes and social jet lag were associated with greater adiposity in adolescent girls but not adolescent boys. Interventions aimed at improving sleep schedules may be useful for obesity prevention, especially in girls.