Christian Benedict

• Associate Professor
• Professor (Associate) at Uppsala University

Context: Shift workers are at increased risk of metabolic morbidities. Clock genes are known to regulate metabolic processes in peripheral tissues, eg, glucose oxidation. Objective: This study aimed to investigate how clock genes are affected at the epigenetic and transcriptional level in peripheral human tissues following acute total sleep depr...

Biomarker profiling from biofluids such as blood are widely measured in clinical research, using for example Olink proteomics panels. One such research focus area is cardiovascular disease (CVD), for which chronic sleep restriction (SR) is a risk factor. However, it remains unclear whether blood levels of commonly measured CVD biomarkers are sensit...

To study the impact of the COVID‐19 pandemic on sleep and circadian rhythms—two fundamental pillars for health—the collaboration International COVID‐19 Sleep Study (ICOSS) was established. The present overview comprehensively discusses the findings from this collaboration. Involving sleep researchers across the globe, ICOSS used a harmonised questi...

Chronic sleep disruption and shift work elevate the risk of neurodegeneration and Alzheimer's disease (AD). While disrupted sleep affects canonical AD biomarkers, its impact on other mechanisms, such as circulating microRNAs (miRNAs), remains less understood. Therefore, we here examined the effects of overnight wakefulness on plasma levels of sever...

Background Lifestyle choices, such as dietary patterns and sleep duration, significantly impact the health of the digestive system and may influence the risk of mortality from digestive system cancer. Methods This study aimed to examine the associations between sleep duration, dietary habits, and mortality from digestive system cancers. The analys...

Obstructive sleep apnea frequently coexists with epilepsy, potentially influencing its pathophysiology. However, the effect of obstructive sleep apnea severity on interictal epileptiform discharges is not well understood. To explore this, we studied 108 Asian patients with epilepsy who underwent single‐night polysomnography. We utilized generalized...

Purpose of Review With the growing body of research examining the link between sleep disorders, including insomnia and obstructive sleep apnea (OSA), and the gut microbiome, this review seeks to offer a thorough overview of the most significant findings in this emerging field. Recent Findings Current evidence suggests a complex association between...

In the context of the escalating global health challenge posed by Alzheimer’s disease (AD), this comprehensive review considers the potential of melatonin in both preventive and therapeutic capacities. As a naturally occurring hormone and robust antioxidant, accumulating evidence suggests melatonin is a compelling candidate to consider in the conte...

Background Preliminary data suggests that obesity might hasten the decline in mRNA vaccine-induced immunity against SARS-CoV-2. However, whether this renders individuals with obesity more susceptible to long COVID symptoms post-vaccination remains uncertain. Given sleep’s critical role in immunity, exploring the associations between obesity, probab...

Importance Understanding the interplay between sleep duration, dietary habits, and the risk of developing type 2 diabetes (T2D) is crucial for public health and diabetes prevention strategies. Objective To investigate the associations of type of diet and duration of sleep with the development of T2D. Design, Setting, and Participants Data derived...

The association between nightmare frequency (NMF) and suicidal ideation (SI) is well known, yet the impact of the COVID-19 pandemic on this relation is inconsistent. This study aimed to investigate changes in NMF, SI, and their association during the COVID-19 pandemic. Data were collected in 16 countries using a harmonised questionnaire. The sample...

Accurate measurement of habitual sleep duration (HSD) is crucial for understanding the relationship between sleep and health. This study aimed to assess the bias and agreement limits between two commonly used short HSD self-report methods, considering sleep quality (SQ) and social jetlag (SJL) as potential predictors of bias. Data from 10,268 parti...

Background Self-rated health (SRH) is widely recognized as a clinically significant predictor of subsequent mortality risk. Although COVID-19 may impair SRH, this relationship has not been extensively examined. The present study aimed to examine the correlation between habitual sleep duration, changes in sleep duration after infection, and SRH in s...

This study aimed to investigate the impact of acute sleep deprivation on the perceived age appearance of individuals, with a particular focus on subjective sleepiness. The study involved 380 anonymous raters who participated in an online survey. The raters were shown photographs of a Caucasian man, aged 48.2 years, and were asked to estimate his ag...

Study objectives: Preliminary evidence suggests that the risk of Long COVID is higher among people with pre-existing medical conditions. Based on its proven adjuvant role in immunity, habitual sleep duration may alter the risk for developing Long COVID. The objective of this study was to determine whether the odds of Long COVID are higher amongst...

Aims: To investigate the association between socioeconomic deprivation and indicators of sleep health among patients with type 2 diabetes mellitus (T2DM), and additionally, to examine whether socioeconomic deprivation is associated with higher glycated haemoglobin (HbA1c) levels in these patients. Materials and methods: We analysed data from the...

This study aimed to investigate the impact of sleep deprivation on the perceived age appearance of individuals, with a particular focus on subjective sleepiness. The study involved 380 anonymous observers who participated in an online survey. The observers were shown photographs of a Caucasian man, aged 48.2 years, and were asked to estimate his ag...

Background: The COVID-19 pandemic and related restriction measures have affected our daily life, sleep, and circadian rhythms worldwide. Their effects on hypersomnolence and fatigue remain unclear. Methods: The International COVID-19 Sleep Study questionnaire which included items on hypersomnolence such as excessive daytime sleepiness (EDS), and...

Background: The health effects of rest-activity rhythm are of major interest to public health, but its associations with health outcomes remain elusive. We aimed to examine the associations between accelerometer-measured rest-activity rhythm amplitude and health risks among the general UK population. Methods: We did a prospective cohort analysis...

The American Diabetes Association recommends a glycated haemoglobin target of less than 7% for treating type 2 diabetes mellitus. However, it is still being determined if poor sleep affects this therapeutic goal, despite being treated with the blood-glucose-lowering medication metformin. Thus, we used data from 5703 patients on metformin monotherap...

Consumer sleep wearables are increasingly popular, even among patients with sleep problems. However, the daily feedback provided by these devices could exacerbate sleep-related worry. To investigate this issue, 14 patients received a self-help guide booklet to improve sleep and wore the sleep tracker Fitbit Inspire 2 on their non-dominant hand for...

Evidence suggests potential links between circadian rhythm and atrial fibrillation (AF). However, whether circadian disruption can predict the onset of AF in the general population remains largely unknown. We aim to investigate the association of accelerometer-measured circadian rest-activity rhythm (CRAR, the most prominent circadian rhythm in hum...

Vaccination is a major strategy to control a viral pandemic. Simple behavioral interventions that might boost vaccine responses have yet to be identified. We conducted meta-analyses to summarize the evidence linking the amount of sleep obtained in the days surrounding vaccination to antibody response in healthy adults. Authors of the included studi...

Background: Obstructive sleep apnea (OSA) is a common sleep-breathing disorder linked to increased risk of cardiovascular disease. Intermittent hypoxia and intermittent airway obstruction, hallmarks of OSA, have been shown in animal models to induce substantial changes to the gut microbiota composition and subsequent transplantation of fecal matte...

There is a growing interest in the role of timing of daily behaviors in improving health. However, little is known about the optimal timing of physical activity to maximize health benefits. We perform a cohort study of 92,139 UK Biobank participants with valid accelerometer data and all-cause and cause-specific mortality outcomes, comprising over 7...

Short nighttime sleep duration impairs the immune response to virus vaccination, and long nighttime sleep duration is associated with poor health status. Thus, we hypothesized that short (<6 h) and long (>9 h) nighttime sleepers have a higher post-COVID risk than normal nighttime sleepers, despite two doses of mRNA vaccine (which has previously bee...

Aims: To examine the associations of disrupted circadian rest-activity rhythm (CRAR) with cardiovascular diseases and mortality among people with type 2 diabetes. Methods: A total of 3147 participants with baseline type 2 diabetes (mean age 65.21 years, 39.78% female; mean HbA1c 50.02 mmol/mol) from UK Biobank were included. The following CRAR p...

Background: Given the significant role of sleep in glycemic control, the association between sleep and glycemic variability determined by continuous glucose monitoring (CGM) is worth investigating among patients with type 2 diabetes (T2D). Methods: CGM was carried out among 28 T2D patients (aged 62.3±4.8 years, 57% women). Sleep characteristics...

Healthy individuals exhibit blood pressure variation over a 24-hour period with higher blood pressure during wakefulness and lower blood pressure during sleep. Loss or disruption of the blood pressure circadian rhythm has been linked to adverse health outcomes, for example, cardiovascular disease, dementia, and chronic kidney disease. However, the...

The present study had two main aims. First, to investigate whether shift/night workers had a higher prevalence and severity of COVID-19 compared with day workers. Second, to investigate whether people regularly working in face-to-face settings during the pandemic exhibited a higher prevalence and severity of COVID-19 compared with those having no n...

Objective: This study investigated whether blood concentrations of leptin, ghrelin, and adiponectin are affected by acute total sleep deprivation in a sex- and weight-specific manner. Methods: A total of 44 participants (mean age 24.9 years; 20 women; 19 with obesity) participated in a crossover design, including one night of sleep deprivation a...

Weighted blankets have emerged as a potential non‐pharmacological intervention to ease conditions such as insomnia and anxiety. Despite a lack of experimental evidence, these alleged effects are frequently attributed to a reduced activity of the endogenous stress systems and an increased release of hormones such as oxytocin and melatonin. Thus, the...

Many people report suffering from post‐acute sequelae of COVID‐19 or “long‐COVID”, but there are still open questions on what actually constitutes long‐COVID and how prevalent it is. The current definition of post‐acute sequelae of COVID‐19 is based on voting using the Delphi‐method by the WHO post‐COVID‐19 working group. It emphasizes long‐lasting...

Aims Increasing evidence suggests that sleep is important for fat metabolism. However, the causal relationship between sleep duration and visceral adipose tissue (VAT) needs to be further clarified. This study investigated the linear and nonlinear causal association between sleep duration and VAT. Methods This study used one-sample and two-sample...

Permanent night shift work is associated with adverse health effects, including elevated blood pressure (BP) and hypertension. Here, we examined the BP response to one night of forced wakefulness in a sitting position in a cohort without night shift work experience. According to a counterbalanced crossover design, 47 young adults with either obesit...

Night shift work impairs vigilance performance, reduces the ability to stay awake, and compromises brain health. To investigate if the magnitude of these adverse night shift work effects differs between sexes and weight groups, 47 men and women with either normal weight or obesity participated in one night of sleep and one night of total sleep loss...

Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder. In animal models, OSA has been shown to alter the gut microbiota; however, little is known about such effects in humans. Here, we used respiratory polygraphy data from 3,570 individuals aged 50-64 from the Swedish CardioPulmonary bioImage Study (SCAPIS) and deep shotgun met...

Objectives: Sleep enhances the consolidation of memories. Here, we investigated whether sleep-dependent memory consolidation differs between healthy subjects and narcolepsy type 1 (NT1) patients. Material and methods: We recruited 18 patients with NT1 and 24 healthy controls. The consolidation of spatial (declarative memory; 2-dimensional object...

Meal timing has significant effects on health. However, whether meal timing is associated with the risk of developing and dying of cancer is not well-researched in humans. In the present study, we used data from 941 community-dwelling men aged 71 years who participated in the Uppsala Longitudinal Study of Adult Men to examine the association of mea...

Background Acute sleep loss increases the brain’s reactivity toward positive and negative affective stimuli. Thus, despite well-known reduced attention due to acute sleep loss, we hypothesized that humans would gaze longer on happy, angry, and fearful faces than neutral faces when sleep-deprived. We also examined if facial expressions are different...

Abstract Purpose: Obstructive sleep apnea (OSA) may increase the risk of severe COVID-19; however, the level of potential modulation has not yet been established. The objective of the study was to determine the association between high risk of OSA, comorbidities, and increased risk for COVID-19, hospitalization, and intensive care unit (ICU) treatm...

The cover image is based on the Original Article No association between a common type 2 diabetes risk gene variant in the melatonin receptor gene (MTNR1B) and mortality among type 2 diabetes patients by Pei Xue et al., https://doi.org/10.1111/jpi.12785.

Objective Physical exercise – especially at high intensity – is known to impose cardiac stress, as mirrored by, e.g., increased blood levels of cardiac stress biomarkers, such as cardiac Troponin T (cTnT) and NT-proBNP. Here, we examined in healthy young participants whether a few nights of short sleep duration alters the effects of acute exercise...

The minor G risk allele in the common melatonin receptor gene (MTNR1B, rs10830963) has been associated with an increased risk of myocardial infarction among patients with type 2 diabetes (T2D). Furthermore, activating the melatonin receptor 1B through melatonin has been shown to promote cell proliferation, which could be hypothesized to increase ca...

Importance: Statins have been linked to an increased risk for insomnia, but the literature is controversial. Moreover, it is unknown, if the potential effects are directly related to the inhibition of the statin target HMGCR, the subsequently lowered cholesterol levels, or other off-target effects of statins. Aims: To investigate the association of...

This protocol paper describes the second survey produced by the International Covid Sleep Study (ICOSS) group with the aim to examine the associations between SARS-CoV-2 infection and sleep, sleepiness, and circadian problems as potential predisposing factors for more severe COVID-19 disease profile and for development of Long-COVID in the general...

Objectives Sleep is important for human health and well-being. No previous study has assessed whether the COVID-19 pandemic impacts sleep and daytime function across the globe. Methods This large-scale international survey used a harmonised questionnaire. Fourteen countries participated during the period of May–August 2020. Sleep and daytime probl...

Previous small-scale studies have found that oral antidiabetic therapy is associated with sleep difficulties among patients with type 2 diabetes (T2D). Here, we used data from 11 806 T2D patients from the UK Biobank baseline investigation to examine the association of oral antidiabetic therapy with self-reported difficulty falling and staying aslee...

Purpose Lifestyle and work habits have been drastically altered by restrictions due to the COVID-19 pandemic. Whether the associated changes in sleep timing modulate the risk of suffering from symptoms of insomnia, the most prevalent sleep disorder, is however incompletely understood. Here, we evaluate the association between the early pandemic-ass...

Background The fat‐to‐muscle mass ratio (FMR) might be an indicator to assess type 2 diabetes risk independent of general obesity. However, no longitudinal studies have explored the extent to which total and regional FMRs may confer risks. We aimed to measure the sex‐specific associations between FMRs of the arm, leg, trunk and whole body and incid...

The hormone fibroblast growth factor 21 (FGF21) modulates tissue metabolism and circulates at higher levels in metabolic conditions associated with chronic sleep–wake disruption, such as type 2 diabetes and obesity. In the present study, we investigated whether acute sleep loss impacts circulating levels of FGF21 and tissue‐specific production, and...

Using one-night sleep recordings from 852 subjects all living in Uppsala, Sweden, the present study represents one of the largest polysomnography investigations into the association of the 29.53-day long lunar cycle with sleep among men and women and across a wide age range (22–81 years). Following the day after the new moon until the day of the fu...

Study Objectives Individual circadian type is a ubiquitous trait defining sleep, with eveningness often associated with poorer sleep and mental health than morningness. However, it is unknown whether COVID-19 pandemic has differentially affected sleep and mental health depending on the circadian type. Here, the differences in sleep and mental healt...

Subjective sleep reports are widely used research tools in epidemiology. Whether sleep reports can differ between seasons is less clear. Using multivariable binary or multinomial logistic regression analyses, in the present Swedish cross-sectional two-centre cohort study (N = 19,254; mean age 61 years), we found that participants surveyed during th...

The human circadian system consists of the master clock in the suprachiasmatic nuclei of the hypothalamus as well as in peripheral molecular clocks located in organs throughout the body. This system plays a major role in the temporal organization of biological and physiological processes, such as body temperature, blood pressure, hormone secretion,...

Importance and Study Objective The COVID-19 pandemic has produced unprecedented changes in social, work, and leisure activities, which all have had major impact on sleep and psychological well-being. This study documented the prevalence of clinical cases of insomnia, anxiety, and depression and selected risk factors (COVID-19, confinement, financia...

Purpose Obstructive sleep apnea (OSA) may increase the risk of severe COVID-19; however, the level of potential modulation has not yet been established. The objective of the study was to determine the association between high risk of OSA, comorbidities, and increased risk for COVID-19, hospitalization, and intensive care unit (ICU) treatment. Meth...

Introduction Preliminary findings suggest that pets may improve the owner’s sleep via companionship, security, physical activity, and relaxation. On the other hand, pets can disrupt the owner’s sleep. Due to the heterogeneity of the results and the low number of studies in this field, more studies with a bigger sample size are needed to explore thi...

The COVID-19 pandemic and related restrictions, such as stay-at-home-orders, have significantly altered daily routines and lifestyles. Given their importance for metabolic health, we herein compared sleep and meal timing parameters during vs. before the COVID-19 pandemic based on subjective recall, in an anonymous Swedish survey. Among 191 adults (...

Preliminary findings suggest that pets may impact the owner’s sleep. By using data from the Swedish CArdioPulmonary bIoimage Study (SCAPIS) cohort, we aimed to investigate the association of pet ownership with the following self-reported sleep outcomes in 3788 to 4574 participants: (i) achieving the recommended daily sleep duration for adults (i.e....

A lower day-to-night systolic blood pressure (BP) dip has previously been associated with poor brain health and cognitive functions. Here, we sought to examine whether reduced (nighttime/daytime ratio of systolic BP >0.9 and ≤1) and reverse (nighttime/daytime ratio of systolic BP >1) dipping of systolic BP is associated with the prospective risk of...

Background Recurrently disrupted sleep is a widespread phenomenon in our society. This is worrisome as chronically impaired sleep increases the risk of numerous diseases that place a heavy burden on health services worldwide, including type 2 diabetes, obesity, depression, cardiovascular disease, and dementia. Therefore, strategies mitigating the c...

Older adults often complain about sleep disturbances, such as difficulty falling asleep and difficulty maintaining sleep in the early morning hours. Here, we investigated whether meal timing is associated with sleep problems in a cohort of older Swedish men (n = 998, mean age 71). Each participant filled out a seven-day food diary used to determine...

Introduction To examine the association of sleep duration, insomnia, and obstructive sleep apnea (OSA) with hemoglobin A1c (HbA1c) in a cohort of patients with type 2 diabetes (T2D) on glucose-lowering medications. Research design and methods 13 346 patients with T2D were included in the present analysis (mean age: 60.2 years; 56.6% were on antidi...

Chronically blunted nocturnal blood pressure (BP) dipping has been shown to increase the future risk of cardiovascular diseases. In the present cross-sectional study, we investigated whether self-reported insomnia symptoms were associated with an altered 24-h BP profile and blunted nocturnal BP dipping (night-to-day BP ratio > 0.90) in older men. F...

A wealth of cross-sectional studies found a link between sleep deprivation and food-related outcomes like energy intake and BMI. Recent experimental studies suggest that this link is causal. However, the mechanisms through which sleep deprivation influences intake remain unclear. Here, we tested two prevailing hypotheses: that sleep deprivation lea...

Objective: The common MTNR1B single nucleotide polymorphism rs10830963 associates with risk of type 2 diabetes mellitus (T2D). Here, we examine the association between this gene variant and the risk of myocardial infarction (MCI) among patients with T2D. MCI is a main cause of death and disability among such individuals. Research design and metho...

Introduction Aging increases the risk of insomnia and elevated blood pressure (BP). Here, we examined in older men whether reports of difficulty falling asleep (DIS) and early morning awakenings (EMA) are associated with 24-h BP and heart rate. Methods We utilized variables from 995 men (mean age: 71 years) who participated in the Uppsala Longitud...

Introduction Ageing is often accompanied by an increased prevalence of sleep problems. Healthy lifestyle choices, including diet, are especially important to mitigate such impairments. To date, little is known about how dietary patterns may link to measures of sleep quality in older subjects. Therefore, we investigated in a Swedish older male popul...

Introduction Chronic sleep loss and aerobic exercise have opposing effects on body weight maintenance. The effects of sleep loss on circulating levels of the orexigenic hormone ghrelin and the anorexigenic hormone leptin have been extensively studied. In contrast, how these changes interact with acute exercise, and whether these changes are reflect...

Background: Ageing is associated with DNA methylation changes in all human tissues, and epigenetic markers can estimate chronological age based on DNA methylation patterns across tissues. However, the construction of the original pan-tissue epigenetic clock did not include skeletal muscle samples and hence exhibited a strong deviation between DNA...

Objective: Disrupted sleep increases CSF levels of tau and β-amyloid (Aβ) and is associated with an increased risk of Alzheimer disease (AD). Our aim was to determine whether acute sleep loss alters diurnal profiles of plasma-based AD-associated biomarkers. Methods: In a 2-condition crossover study, 15 healthy young men participated in 2 standar...

Background Ageing is associated with DNA methylation changes in all human tissues, and epigenetic markers can estimate chronological age based on DNA methylation patterns across tissues. However, the construction of the original pan-tissue epigenetic clock did not include skeletal muscle samples, and hence exhibited a strong deviation between DNA m...