Author Interviews, Circadian Rhythm, Heart Disease, Occupational Health, Sleep Disorders / 27.04.2021

Circadian misalignment is associated with a high cardiovascular risk among shift workers: Interview with: Sara Gamboa Madeira Medical Doctor - General & Family Physician PhD Student - EnviHealth&Co - Faculty of Medicine Lisbon University What is the background for this study? Response: One in every five employees work in shifts across Europe1. Shift work have been associated with an increased risk for several cardiovascular diseases2 and three main mechanism have been proposed: unhealthy behaviours, disturbed sleep, and circadian misalignment. This study focused on the role of circadian misalignment, which we assessed via social jetlag. Social jetlag is calculated using the Munich Chronotype Questionnaire3 by the difference between sleep behaviour on free-days (mainly driven by the individual “biological clock”, also called chronotype) and sleep behaviour on workdays (mainly drive by the “social clock”, namely work schedules). Chronotype is an individual feature which ranges from early/morning people to late/evening people (from proverbial lark to owls), with the majority of the population falling in between as a Gaussian distribution. Therefore higher levels of social jetlag mean a greater mismatch between what your biological clock need (e.g. go to sleep at 9pm) and what your social obligations impose on you (e.g. work until midnight). (more…)
Author Interviews, BMJ, Circadian Rhythm, JAMA, Occupational Health / 27.02.2021 Interview with: Dr Tapio Räihä Center for Life Course Health Research University of Oulu, Oulu, Finland What is the background for this study? sleep-work-occupational-chronotypeResponse: In ageing societies, understanding risk factors for pre-term disability pensions and poor work ability is an important research priority. We studied whether individual-level chronotype could contribute to these.  Previous research has shown that evening chronotypes (E-types) have poorer health compared with morning chronotypes (M-types), and that E-types may have difficulties to function during standard morning working hours. This study was the first population-level study with register linkage to find out whether eveningness would be associated with poor work ability and disability pensions, too. We surveyed chronotype (with the Morningness–Eveningness Questionnaire) among 5831 non-retired Finns born in 1966 when they were at age 46 years, and compared it with their current perceived work ability. We then followed the emergence of new registered disability pensions during the next 4 years. Multivariate logistic and Cox regression analyses of the associations between chronotype and the outcomes were separately adjusted for sleep, health and behaviours, sociodemographic and economic factors, or working times  (more…)
Author Interviews, Circadian Rhythm, Exercise - Fitness / 11.12.2020 Interview with: Andrew W. McHill, PhD Research Assistant Professor Oregon Institute of Occupational Health Sciences Oregon Health & Science University, Portland OR Portland, OR 97239 What is the background for this study? Response: It has long been known that there is a home court advantage in sports, whether it be due to the home fans cheering, playing within familiar settings, or travel of the opposing team. However, the contribution of travel to home-court advantage could never be fully teased apart due to all the confounds of the other aspects of playing at home. In March, the National Basketball Association had to pause their season due to COVID-19 concerns, only to start again several months later with the top 22 teams playing in a “bubble” environment where no teams were required to travel. This created a ‘natural experiment’ wherein we could test the impact of travel on winning and performance before the COVID-19 shutdown with games played in the bubble environment with no travel. (more…)
AHA Journals, Author Interviews, Blood Pressure - Hypertension, Circadian Rhythm / 05.11.2020 Interview with: Kazuomi Kario, MD, PhD, FACP, FACC, FAHA, FESC, FJCS Professor, Chairman Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University School of Medicine (JMU) JMU Center of Excellence, Cardiovascular Research and Development (JCARD) Hypertension Cardiovascular Outcome Prevention and Evidence in Asia (HOPE Asia) Network Shimotsuke, Tochigi, 329-0498, JAPAN What is the background for this study? Response: To date, it remains unclear whether disrupted blood pressure (BP) circadian rhythm is associated with adverse outcomes independent of nighttime BP. The JAMP study includes 6359 outpatient population who had ambulatory BP monitoring to evaluate the association between both nocturnal hypertension and nighttime BP dipping patterns and the occurrence of cardiovascular events in patients with hypertension. (more…)
Author Interviews, Circadian Rhythm, COVID -19 Coronavirus, Sleep Disorders / 15.06.2020 Interview with: Dr. Christine Blume PhD Centre for Chronobiology Psychiatric Hospital of the University of Basel Transfaculty Research Platform Molecular and Cognitive Neurosciences Basel What is the background for this study? Response: In modern societies, human rest-activity rhythms and sleep are between the often-conflicting poles of external social time (e.g., work hours and leisure activities) and an individual’s internal biological time. This can lead to so-called “social jetlag”, which has repeatedly been associated with detrimental health effects. With the restrictions to control the pandemic, social timing relaxed as people many started working from home and public life came to a standstill. In an online survey with 435 respondents, we investigated the effects of the phase with the strictest COVID-19 restrictions on the relationship between social and biological rhythms as well as sleep during a six-week period (mid-March until end of April 2020) in three European societies (Austria, Germany, Switzerland). (more…)
Author Interviews, Circadian Rhythm, Gastrointestinal Disease, Genetic Research, Weight Research / 13.10.2019 Interview with: Marco Colonna, MD Robert Rock Belliveau MD Professor Pathology & Immunology Washington University School of Medicine Qianli Wang MD-PhD Student MSTP student Washington University School of Medicine What is the background for this study? Response: Many aspects of the mammalian digestive system including gut motility, nutrient absorption, and microbiota follow a daily rhythm. This circadian rhythm is generated by the cyclic expressions of molecular clock genes thought to be present in most cells. Group 3 innate lymphoid cells (ILC3) are lymphocytes residing in the intestinal mucosa that respond rapidly to activation in both homeostatic and inflammatory settings. Namely, ILC3s help maintain the mucosal barrier, regulate epithelial lipid transport, and protect against bacterial enteric infections. As tissue resident cells within the highly dynamic and rhythmic environment of the intestine, it may be advantageous for ILC3s to also be synchronized with the circadian rhythm.  (more…)
Author Interviews, Brigham & Women's - Harvard, Weight Research / 09.11.2018 Interview with: "Compare-the-Use-of-Carbohydrates-and-Lipids-in-Energy-Storage" by Zappys Technology Solutions is licensed under CC BY 2.0Kirsi-Marja Zitting, Ph.D. Instructor in Medicine, Harvard Medical School Division of Sleep and Circadian Disorders Departments of Medicine and Neurology Brigham and Women’s Hospital Boston, MA 02115 What is the background for this study? Response: This study is a follow-up study to our previous study where we found that chronic insufficient sleep together with chronic jet lag is associated with adverse changes in metabolism, including increase in blood sugar levels (Buxton et al. Science Translational Medicine, 2012). The present study focuses on the influence of the time of day on metabolism, which has not been investigated in humans independent of the effects of sleep, physical activity and diet. (more…)
Author Interviews, Cancer Research, Circadian Rhythm, Nutrition / 19.07.2018 Interview with: “Christmas Roast and Ham Dinner. Had Tamales for Christmas Eve and Christmas morning. #Roast #Ham #ChristmasDinner #Christmas #Champagne #Dinner #Foodstagram” by Yvonne Esperanza is licensed under CC BY 2.0Manolis Kogevinas, MD, PhD Research Professor NCDs & Environment Group Barcelona Institute for Global Health (ISGlobal) - Campus MAR Barcelona Biomedical Research Park (PRBB) (office 194) Barcelona, Spain What is the background for this study? What are the main findings? Response: We did the study for two main reasons. (i) breast and to a less extent prostate cancer are the cancers that have been associated with night shift work and resulting circadian disruption (disruption of the natural day-light cycle); (ii) experimental studies in animals indicate that timing of diet is important. For example, giving an hypercaloric diet to mice during the day results in obesity, while giving the same diet during the night does not. Mice are nocturnal animals and this means that there normal eating time is the night when they can metabolise what they eat. So, would something similar affect humans? When we eat in late hours at a time when “normally” (normally in the sense of evolution) we would be resting. In this study we show that adherence to a more diurnal eating pattern and specifically an early supper and a long interval between last meal and sleep are associated with a lower breast and prostate cancer risk. Specifically having super before 9pm and having an interval of 2 hours between the last big meal and sleep, were both associated with an approximately 20% prevention of breast and prostate cancer) compared to those who have supper after 10pm or those who eat and then sleep very close after supper. Also, the strongest protection was found in “morning types” as compared to “evening types”. Morning types are expected to function worse than evening types in late evening so late suppers may have more adverse effects on them. (more…)
Author Interviews, Circadian Rhythm, Microbiome, Occupational Health, PNAS / 15.07.2018 Interview with: Dr. Hans Van Dongen, PhD Director of the Sleep and Performance Research Center. ELSON S. FLOYD COLLEGE OF MEDICIN Washington State University Spokane, WA What is the background for this study? Response: Night shift workers are at increased risk of metabolic disorders, including obesity and type 2 diabetes, as well as cardiovascular disease, chronic kidney disease, and cancer. Although it is believed that the biological clock – the master circadian clock in the brain – plays an important role in these adverse chronic health consequences of night shift work, the underlying mechanisms are not well understood. (more…)
Author Interviews, Circadian Rhythm, Lancet, Mental Health Research / 16.05.2018 Interview with: Laura Lyall MA; MSc; PhD Research Associate Institute of Health and Wellbeing University of Glasgow What is the background for this study? Response: Previous studies have suggested a link between disturbed circadian rhythms and depression and bipolar disorder. These studies have however usually used small samples, subjective measures of circadian disruption, or have not accounted for potential confounding factors like sociodemographic and lifestyle characteristics. The UK Biobank cohort has accelerometry (activity monitor) data as well as mental health, lifestyle, BMI and sociodemographic data for over 91,000 individuals, and means we can address this question using objective measures of circadian rhythmicity on a large scale. We derived a measure of relative amplitude from the UK Biobank’s accelerometry data, which was recorded for 7 days between 2013-2014 from around 100,000 participants. Relative amplitude reflects the distinction, in terms of activity levels, between an individual’s most active 10 hours and least active 5 hours, in an average day. If an individual is inactive during the day, or has disturbed sleep at night, the will show low relative amplitude, consistent with disturbed circadian rest-activity patterns. (more…)
Aging, Author Interviews, Circadian Rhythm, Sleep Disorders / 29.03.2018 Interview with: “Woman sleeping” by Timothy Krause is licensed under CC BY 2.0Dr Gurprit S. Lall BSc, MSc, PhD, PGCHE, FHEA Medway School of Pharmacy Interim Deputy Head of School Senior Lecturer in Pharmacology Director of Graduate Studies (Research), University of Kent at Medway Chatham Maritime, Chatham, Kent What is the background for this study? What are the main findings? Response: Medical advancement in prevention and diagnosis of disease has increased life expectancy significantly, thus generating an ageing population far greater than previously seen.  Because of this, it is essential that we begin to understand the ageing process, together with the health implications associated with senescence.  Recent research has found that changes in the circadian clock, located in the brain, play a contributing role in the decline of many physiological and behavioural traits observed through the ageing process.  One example of this, which is commonly seen in the elderly is a decline in sleep-wake cycle regulation; typically presenting as disrupted sleeping patterns. The circadian clock, in mammals, possesses the ability to integrate our social lifestyle choices with the environmental day-night cycle to generate a 24-hour rhythm to which our physiological functions are synchronised.  It is this synchronisation that plays a vital role in regulating many of our behavioural outputs, such as sleeping-wake patterns.  This clock takes its strongest timing cue from the natural day night cycle governed by the duration of daily sunlight. Our study investigated the changes in the interpretation of this light signal by the circadian clock as we age and its impact on function.  We found that the clock became less responsive to light stimuli at both the level of clock cells and at driving behavioural activity.  We were able to narrow this down to changes in the proteins within cells that relay light information to the molecular time setting machinery.  In detail, light signals are relayed to the clock through an excitatory neurotransmitter called glutamate and this signal is predominantly relayed through NMDA receptors located on the surface of clock cells.  It is the configuration of the NMDA receptor that alters as we age and this leads to the clock becoming less responsive to light. (more…)
Abuse and Neglect, Circadian Rhythm, Heart Disease, Lancet, Surgical Research / 03.11.2017 Interview with: Prof David Montaigne MD Faculté de Médecine de Lille H Warembourg Lille, France What is the background for this study? What are the main findings? Response: It is well known for many decades that cardiovascular diseases exhibit a diurnal variation with for instance higher incidence of myocardial infarction in the early morning as opposed to the evening. Although studies on circadian gene knock-out and mutant mice argue for a biorhythm in myocardial ischemia-reperfusion tolerance, whether a biorhythm in the myocardial tolerance to ischemia, exists in humans was unclear because of conflicting reports in the context of myocardial infarction. We demonstrated for the first time in humans that the myocardial tolerance to ischemia-reperfusion is different along the day, in line with rodent experiments performed in the early 2010s. We demonstrated that this biorhythm is clinically meaningful and that it can be targeted as a cardioprotective strategy. In this topic, Rever-alpha is of specific interest. It belongs at the same time to circadian genes and nuclear receptor families: being a nuclear receptor, it is a feasible pharmacological target, conversely to other circadian genes. (more…)
Author Interviews, Circadian Rhythm, Neurological Disorders, Neurology / 21.04.2017 Interview with: Dr. Christine Blume PhD Post-Doctoral Researcher University of Salzburg Centre for Cognitive Neuroscience (CCNS) Laboratory for Sleep, Cognition & Consciousness Research Salzburg What is the background for this study? What are the main findings? Response: We are governed by rhythmic processes. Many of these processes follow a circadian pattern, that is, they have a period length of approximately 24 hours and are under tight control of a biological master clock located in the suprachiasmatic nucleus of the hypothalamus. Given the circadian variation in global states like alertness, it is not surprising that consciousness also varies rhythmically in healthy individuals, it follows the sleep-wake cycle. From a clinical perspective, misalignment of circadian rhythms, which occurs when the sleep-wake schedule is at odds with the light-dark cycle as in the case of night shifts, can cause considerable stress, have detrimental effects on the immune system and impair cognitive abilities. Despite the knowledge that entrained circadian rhythms are important for healthy body and brain functioning, very little is known about circadian rhythms in patients diagnosed with a disorder of consciousness (DOC) following severe brain injuries. We argue that studying circadian rhythms in DOC patients may be especially interesting and important for two reasons. First, the presence or absence of circadian rhythms as well as anomalies in them could be informative about the state of the patient as well as their potential for recovery. Second, this could provide information about time points that best capture remaining cognitive functions thereby minimising the risk of misdiagnoses. Beyond this, examining circadian processes may also provide targets for therapeutic interventions such as light stimulation, which has proven successful in individuals with e.g. circadian sleep disorders. Interestingly, analyses with Lomb-Scargle periodograms revealed significant circadian rhythmicity in all patients (range 23.5-26.3h). We found that especially scores on the arousal subscale of the Coma Recovery Scale-Revised (CRS-R) were closely linked to the integrity of circadian variations in body temperature. Finally, we piloted whether bright light stimulation could boost circadian rhythmicity and found positive evidence in two out of eight patients. (more…)
Author Interviews, Circadian Rhythm, Nutrition, Sleep Disorders, Weight Research / 01.03.2017 Interview with: Mirkka Maukonen MSc (nutrition), PhD Candidate the National Institute for Health and Welfare, Department of Public Health Solutions Helsinki, Finland What is the background for this study? Response: Recent literature has highlighted the importance of sleep and circadian rhythms in development of obesity and metabolic dysfunctions. Furthermore, it has been suggested that in addition to quality of the diet also meal timing may play role in development of obesity. For example, skipping breakfast and eating at later times in the evening have been associated with higher BMI. However, little is known about how the timing of circadian rhythms (chronotype) affects timing of energy intake and its association with metabolic health. (more…)
Author Interviews, Circadian Rhythm, Sleep Disorders / 22.12.2016 Interview with: Dr. Nicola Barclay, BA(Hons), MSc, PhD. Lecturer in Sleep Medicine Sleep and Circadian Neuroscience Institute (SCNi) Nuffield Department of Clinical Neurosciences Sir William Dunn School of Pathology University of Oxford What is the background for this study? Response: We know that extreme sleep deprivation impairs our cognitive functions, particularly attention. This impairment in attention is likely to be driven by physiological mechanisms that change across the waking day (increasing sleep pressure), but also by factors associated with our biological clock. The timing of physiological processes particularly related to attention differ between morning and evening type people (our so called early morning larks and night owls), and so we hypothesised that morning and evening types would differ in their impairments in attention at different times of day, prior to and following 18 hours of sustained wakefulness. (more…)
Author Interviews, Sleep Disorders / 25.03.2015 Interview with: Richard G. Stevens, Ph.D., Professor, Cancer Epidemiologist UConn Health Medical Research: What is the background for this study? What are the main findings? Dr. Stevens: Since first introducing the concept of a possible connection between exposure to light at night and breast cancer in the mid-80s, we’ve seen growing evidence of how artificial light can suppress the circadian hormone melatonin and bring about physiological changes. The extent of this “circadian disruption” varies by the type of light and the time of day. Humans evolved with a body clock that followed the solar clock. Nature intended us to be awake in daylight and at rest in the dark of night. Therefore, the intense, short-wavelength light of the sun in the morning triggers us to become awake and alert, just as the absence of sunlight in the evening allows our body to produce melatonin. Even with the use of fire to provide light in the evening, the circadian impact was relatively minimal because of firelight’s place on the red end of the visible spectrum. Humans survived under this simple formula for many thousands of years. Then electric light started to take an increasingly strong foothold in everyday life. Today we are typically surrounded at all hours of the day and night by artificial light – in many cases it’s not bright enough during the day to match the sun, and it’s too bright at night to be conducive to the natural sleep/wake cycle. Think computer screens, tablets, smart phones, e-readers, etc. These devices emit enough short-wavelength, or blue, light to disrupt our body clocks in the evening. So do fluorescent and LED lights. Our paper – I worked with Dr. Yong Zhu from Yale on this – represents a new analysis and synthesis of what we know up to now on the effect of lighting on our health. We don't know for certain, but there's growing evidence that the long-term implications of this may have ties to breast cancer, obesity, diabetes, and depression, and possibly other cancers. Exposure to electric light  started about 130 years ago,  which is a tiny period of time in evolutionary terms. In other words, not long enough to undo human evolution. (more…)
Author Interviews, BMJ, Circadian Rhythm, Cognitive Issues, Metabolic Syndrome, Occupational Health / 04.11.2014

Dr. Philip Tucker Department of Psychology | Yr Adran Seicoleg College of Human and Health Sciences | Coleg y Gwyddorau Dynol ac lechyd Swansea University | Prifysgol Abertawe Singleton Park | Parc Singleton Swansea | Abertawe  Medical Research: What is the background for this Interview with: Dr. Philip Tucker Department of Psychology | Yr Adran Seicoleg College of Human and Health Sciences | Coleg y Gwyddorau Dynol ac lechyd Swansea University | Prifysgol Abertawe Singleton Park | Parc Singleton Swansea | Abertawe Medical Research: What is the background for this study? What are the main findings? Dr. Tucker: Shift work, like jet-lag, is known to disrupt workers’ normal circadian rhythms (i.e. their body clocks) and their social life. It is also associated with greater risk of developing ulcers, cardiovascular disease, metabolic syndrome, breast cancer and reproductive problems. Several studies have also shown that shift workers experience heightened fatigue and sleepiness, particularly at night, and this may affect job performance and safety. However, very little is known about the long-term consequences of shift work on cognitive abilities. We followed a large sample of shift workers and non-shift workers over 10 years, testing their cognitive performance every 5 years. We found that the shift workers’ cognitive performance was lower than that of the day workers.  The difference was greatest for those who had worked shifts for more than 10 years. The shift workers’ cognitive function recovered after they quit shift work, but this recovery took at least 5 years from time that they stopped working shifts. The effects could not be attributed to poorer sleep quality among shift workers. Rather, it seems likely that the findings reflect the disruption of the shift workers’ circadian rhythms, which as been shown by other researchers to have an impact on brain structures involved in cognition and mental health over the lifespan. (more…)
Author Interviews, Circadian Rhythm, Gastrointestinal Disease, Sugar / 23.05.2014

Dr. Robin Voigt PhD Department of Internal Medicine Division of Gastroenterology Rush University Medical Center Chicago, Interview with: Dr. Robin Voigt PhD Department of Internal Medicine Division of Gastroenterology Rush University Medical Center Chicago, Illinois MedicalResearch: What are the main findings of the study?  Dr. Voigt: We found that chronic circadian rhythm disruption has no effect on the intestinal microbiota when mice are fed a standard chow diet but when combined with a high-fat, high-sugar diet circadian rhythm disruption results in intestinal dysbiosis and an increase in pro-inflammatory bacteria. (more…)
JAMA, Smoking / 29.10.2013 Interview with: John W. Ayers, PhD, MA Graduate School of Public Health San Diego State University, San Diego, California What are the main findings of the study? Dr. Ayers: Our study, published today in the Journal of the American Medical Association, Internal Medicine was the first to describe daily rhythms in health behaviors. Because trends in quitting contemplations are usually described annually using telephone surveys, we had to use a novel data source that could capture daily patterns. By monitoring aggregate Internet search queries we can see precisely what the population is thinking about by the content of their queries and that the population is engaged in the issue by searching. We therefore analyzed daily search volumes for smoking cessation queries (e.g., "quit smoking") in six languages across the entire globe. We found that people search about quitting smoking more often early in the week, with the highest query volumes on Mondays, using a daily measure representing the proportion of quit smoking searches to all searches. This pattern was consistent across all six languages, suggesting a global predisposition to thinking about quitting smoking early in the week, particularly on Mondays. English searches, for example, showed Monday query volumes were 11 percent greater than on Wednesdays, 67 percent greater than on Fridays, and 145 percent greater than on Saturdays. In total for all six languages, Monday query volumes were 25 percent higher than the combined mean number of searches for Tuesday through Sunday. Practically these findings are very meaningful. For example, in English alone there are about 150,000 more quit smoking queries on Monday than on a typical day; about 8,000,000 over an entire year. (more…)
Author Interviews, Gastrointestinal Disease, PLoS, Sleep Disorders / 04.07.2013

Keith Summa MD/PhD Student Northwestern University Feinberg School of Medicine Chicago, Illinois, United States of Interview with: Keith Summa MD/PhD Student Northwestern University Feinberg School of Medicine Chicago, Illinois, United States of America   Disruption of the Circadian Clock in Mice Increases Intestinal Permeability and Promotes Alcohol-Induced Pathology and Inflammation What are the main findings of the study? Answer: The main findings of the study were that disruption of circadian rhythms, which we achieved using independent genetic and environmental strategies in mice, leads to impaired function of the intestinal epithelial barrier. This loss of epithelial barrier integrity, which has been associated with numerous diseases, results in "gut leakiness," a phenomenon in which endotoxin from gut bacteria can cross the intestinal wall and enter circulation, promoting inflammation. In particular, using in a disease model of gut-derived endotoxemia and inflammation, alcoholic liver disease, we found the circadian disruption interacted with alcohol, leading to increased gut leakiness, inflammation and liver damage. (more…)