Impact of sleep debt on metabolic and endocrine function

Eating habits and sleep quality in individuals with type 1 diabetes on continuous glucose monitoring and insulin pump

BACKGROUND AND AIMS

Sleep disorders are bidirectionally linked with eating behaviors and glucose metabolism, which could be clinically relevant in type 1 diabetes (T1D). We investigated the relationship between dietary habits and sleep quality in individuals with T1D on insulin pumps and continuous glucose monitoring (CGM).

METHODS AND RESULTS

In a cross-sectional study, dietary habits (7-day food diary, EPIC questionnaire) and sleep quality (Pittsburgh Sleep Quality Index questionnaire) were assessed in 59 men and 58 women with T1D, aged 19-79 years, using CGM and insulin pump. Differences in dietary habits and blood glucose after dinner (6 h) between participants differing in sleep quality, sleep duration, and sleep onset latency were evaluated. Bad Sleepers (n = 81) were twice as prevalent as Good Sleepers (n = 36) and had a significantly higher intake of fat than Good Sleepers (dinner: 30.7 ± 10.7 vs. 24.0 ± 10.5 g, p = 0.004). Short sleepers had a significantly higher usual intake (g/1000 kcal) of coffee and tea (90.4 ± 71.7 vs. 62.0 ± 35.6), alcoholic (47.8 ± 51.1 vs. 28.9 ± 31.5) and carbonated beverages (21.8 ± 38.1 vs. 9.3 ± 17.2) (p < 0.05 for all) than Long Sleepers. Long Sleep Onset Latency was associated with a significantly higher fat intake at dinner (41.8 ± 7.4 vs. 38.1 ± 9.1 % total energy, p = 0.029) than Short Sleep Onset Latency. No significant differences in post-dinner blood glucose levels were detected between participants with good or bad sleep quality.

CONCLUSION

Sleep disruption is common in T1D and is associated with unhealthy dietary choices, especially at dinner, independently of post-dinner blood glucose control.

Short Sleep Duration Disrupts Glucose Metabolism: Can Exercise Turn Back the Clock?

Short sleep duration is prevalent in modern society and may be contributing to type 2 diabetes prevalence. This review will explore the effects of sleep restriction on glycemic control, the mechanisms causing insulin resistance, and whether exercise can offset changes in glycemic control. Chronic sleep restriction may also contribute to a decrease in physical activity leading to further health complications.

Association between weekend catch-up sleep and depressive symptoms in American adults: Finding from NHANES 2017-2020

BACKGROUND

The effect of weekend catch-up sleep (WCS) on depressive symptoms is inconsistent among different populations, with limited evidence in Americans. Therefore, we aimed to investigate the association between WCS and depressive symptoms in American adults.

METHODS

We recruited 7719 participants from the National Health and Nutrition Examination Survey (NHANES) 2017-2020. Information on sleep duration and depressive symptoms were assessed by several self-reported questions and Patient Health Questionnaire-9 (PHQ-9), respectively. Then, WCS duration was calculated as weekend sleep duration minus weekday sleep duration, and WCS was further defined as WCS duration >0 h. Survey designed regression analyses were used to assess the association of WCS and depressive symptoms.

RESULTS

In fully adjusted multivariate logistic regression models, the odds ratio (95 % confidence interval) for depressive symptoms and the β (95 % confidence interval) for PHQ-9 score in response to WCS were 0.746 (0.462, 1.204; P = 0.218) and -0.429 (-0.900, 0.042; P = 0.073), respectively. Besides, the smooth relationship presented L-shaped, and only WCS duration of 0-2 h was statistically significantly associated with depressive symptoms or PHQ-9 score. Subgroup analyses showed that the negative associations were stronger among men, adults younger than 65 years, and those with short weekday sleep duration (P for interaction <0.05).

LIMITATIONS

The cross-sectional design limits the capability for causal relationship between WCS and depressive symptoms.

CONCLUSIONS

This study suggests that moderate WCS is associated with reduced odds of depressive symptoms, which provides additional epidemiological evidence for the effects of sleep on depressive symptoms.

Effects of Testosterone in Mediating the Relationship Between Daytime Napping and Osteoporosis in European Populations: A Mendelian Randomization Study

We aimed to explore the causal effect of daytime napping on the risk of osteoporosis and the mediation role of testosterone in explaining this relationship. Summary data for Mendelian randomization (MR) analysis were obtained from the IEU OpenGWAS database. Univariable MR(UVMR) analysis and multiple sensitivity analyses were applied to explore the casual relationship between daytime napping and bone mineral density (BMD)/osteoporosis. We also conducted multivariable Mendelian randomization (MVMR) analysis to evaluate the correlation between testosterone-associated single-nucleotide variations and BMD/osteoporosis. Then, mediation analysis was performed to explore whether the association between daytime napping and BMD/osteoporosis was mediated via testosterone. Genetically predicted daytime napping was significantly associated with femoral neck BMD (β [95% CI]: 0.2573 [0.0487, 0.4660]; P = 0.0156), lumbar spine BMD (β [95% CI]: 0.2526 [0.0211, 0.4840]; P = 0.0324), and osteoporosis (OR [95% CI]: 0.5063 [0.2578, 0.9942]; P = 0.0481). β and 95%CIs indicate the standard deviation (SD) unit of BMD increase per category increase in daytime napping. OR and 95%CIs represent the change in the odds ratio of osteoporosis per category increase in daytime napping. We observed a potentially causal effect of more frequent daytime napping on higher BMD and a lower risk of osteoporosis. Daytime napping was causally associated with a higher level of bioavailable testosterone (β [95% CI]: 0.1397 [0.0619, 0.2175]; P = 0.0004). β and 95%CIs represent the change in the SD of testosterone per category increase in daytime napping. Furthermore, the causal effects of daytime napping on BMD/osteoporosis were partly mediated by bioavailable testosterone. Daytime napping can efficiently increase BMD and reduce the risk of osteoporosis, and testosterone plays a key mediating role in this process.

The association of self-reported sleep and circadian measures with glycemic control and diabetes complications among young adults with type 2 diabetes

We aim to examine the association of sleep duration, sleep quality, late chronotype, and circadian misalignment with glycemic control and risk of complications in young adults with youth-onset type 2 diabetes followed in the Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study. Self-reported sleep duration, quality, timing, and circadian misalignment were assessed via a modified Pittsburgh Sleep Quality Index (PSQI) questionnaire, and chronotype was assessed via the Morningness-Eveningness Questionnaire (MEQ). We examined diabetes complications including loss of glycemic control (defined as hemoglobin A1c ≥8%), hypertension, dyslipidemia, albuminuria, and diabetic peripheral neuropathy. Multivariable logistic regression models were constructed to assess associations between sleep and circadian measures with outcomes of interest, such as loss of glycemic control and diabetes complications. A total of 421 participants (34.2% male), mean age 23.6 ± 2.5 yr, mean body mass index (BMI) of 36.1 ± 8.3 kg/m2, and mean diabetes duration of 10.0 ± 1.5 yr were evaluated. Self-reported short sleep duration, daytime sleepiness, and sleep quality were not associated with loss of glycemic control or diabetes complications. Late self-reported bedtime (after midnight) on work/school nights, rather than self-expressed chronotype or circadian misalignment, was independently associated with loss of glycemic control. An association was seen between late bedtimes and albuminuria but was attenuated after adjusting for depression. In conclusion, late bedtime on work/school days, rather than short sleep duration, daytime sleepiness, or poor sleep quality, was independently associated with loss of glycemic control in this longitudinal cohort of young adults with youth-onset type 2 diabetes.NEW & NOTEWORTHY The prevalence of type 2 diabetes in youth is increasing at an alarming rate. Identifying potentially modifiable factors modulating glycemic control is critically important to reduce micro and macrovascular complications. In a large cohort of youth-onset type 2 diabetes, self-reported late bedtime on work/school days was independently associated with loss of glycemic control in this longitudinal cohort of young adults with youth-onset type 2 diabetes.

Associations of meal timing and sleep duration with incidence of obesity: a prospective cohort study

OBJECTIVES

Late mealtime and short sleep are known to be associated with obesity risk due to a misaligned circadian rhythm. This study aimed to investigate the relationship between obesity and mealtime and sleep duration using the Korean Genome and Epidemiology Study (KoGES) data.

DESIGN

Longitudinally prospective cohort study.

SETTING

Population-based.

PARTICIPANTS

KoGES analysed data from 9,474 Korean adults with an average age of 54- years old at baseline.

MEASUREMENTS

Meal timing was defined as the eating occasions of the day reported by the participant eating a 24-h dietary recall method. Sleep duration was categorized as <6, 6-7, 7-8, and ≥8 h. The Cox proportional hazard model was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for incident obesity according to meal timing, sleep duration, and nightly fasting duration.

RESULTS

During a mean follow-up of 3.5 years, 826 participants developed obesity. In the multivariable-adjusted analysis, midnight snack eating (HR, 1.20; 95% CI, 1.02-1.41) and higher energy intake from midnight snacks (HR, 1.26; 95% CI, 1.06-1.49) were associated with a higher risk of obesity. Sleeping 8 h or more (HR, 0.67; 95% CI, 0.53-0.85) was associated with a lower risk of obesity.

CONCLUSIONS

Our findings highlight the importance of meal and sleep times and suggest that healthy eating habits related to the time of day.

Sleep disorders as both risk factors for, and a consequence of, stroke: A narrative review

BACKGROUND AND PURPOSE

Sleep disorders are increasingly implicated as risk factors for stroke, as well as a determinant of stroke outcome. They can also occur secondary to the stroke itself. In this review, we describe the variety of different sleep disorders associated with stroke and analyze their effect on stroke risk and outcome.

METHODS

A search term-based literature review ("sleep," "insomnia," "narcolepsy," "restless legs syndrome," "periodic limb movements during sleep," "excessive daytime sleepiness" AND "stroke" OR "cerebrovascular" in PubMed; "stroke" and "sleep" in ClinicalTrials.gov) was performed. English articles from 1990 to March 2023 were considered.

RESULTS

Increasing evidence suggests that sleep disorders are risk factors for stroke. In addition, sleep disturbance has been reported in half of all stroke sufferers; specifically, an increase is not only sleep-related breathing disorders but also periodic limb movements during sleep, narcolepsy, rapid eye movement (REM) sleep behavior disorder, insomnia, sleep duration, and circadian rhythm sleep-wake disorders. Poststroke sleep disturbance has been associated with worse outcome.

CONCLUSION

Sleep disorders are risk factors for stroke and associated with worse stroke outcome. They are also a common consequence of stroke. Recent guidelines suggest screening for sleep disorders after stroke. It is possible that treatment of sleep disorders could both reduce stroke risk and improve stroke outcome, although further data from clinical trials are required.

Sex differences in sleep, circadian rhythms, and metabolism: Implications for precision medicine

The number of individuals experiencing sleep loss has exponentially risen over the past decades. Extrapolation of laboratory findings to the real world suggests that females are more affected by extended wakefulness and circadian misalignment than males are. Therefore, long-term effects such as sleep and metabolic disorders are likely to be more prevalent in females than in males. Despite emerging evidence for sex differences in key aspects of sleep-wake and circadian regulation, much remains unknown, as females are often underrepresented in sleep and circadian research. This narrative review aims at highlighting 1) how sex differences systematically impinge on the sleep-wake and circadian regulation in humans, 2) how sex differences in sleep and circadian factors modulate metabolic control, and 3) the relevance of these differences for precision medicine. Ultimately, the findings justify factoring in sex differences when optimizing individually targeted sleep and circadian interventions in humans.

The mediating effect of sleep duration on metabolic syndrome severity in adults: a structural equation modeling approach

BACKGROUND

Metabolic syndrome (MetS) is associated to sleep duration. It is crucial to identify factors that disrupt sleep regulation. The study aimed to assess the indirect effect of risk factors related to MetS severity through sleep duration by utilizing a structural equation model (SEM).

METHODS

The study involving 3,935 adults from the baseline data of the Ravansar Non-Communicable Disease (RaNCD) cohort study. MetS severity scores were the outcome variables. SEM was employed to explore the relationships, utilizing IBM SPSS and AMOS version 23.

RESULTS

The mean MetS severity score was higher in women compared to men (0.25 vs. 0.16, P = 0.003). In men, socioeconomic status (SES) has a positive direct effect (β = 0.048) and a negative indirect effect (β=-0.006) on MetS severity. Increased physical activity is directly (β=-0.036) and indirectly (β=-0.093) associated with reducing MetS severity. Nap duration is directly linked to an increase (β = 0.072) but has an indirect effect (β=-0.008) in decreasing MetS severity. In women, SES has a direct (β=-0.020) and indirect (β=-0.001) inverse relationship with MetS severity. Increased physical activity is directly (β=-0.048) and indirectly (β=-0.036) associated with decreasing MetS severity in women. Nap duration is directly associated with an increase in MetS severity (β=-0.018) but indirectly contributes to its reduction (β=-0.002). Sleep duration not only directly affects MetS severity but is also influenced by age, SES, physical activity, obesity and nap duration.

CONCLUSION

Physical activity, SES, and nap duration directly and indirectly effect the MetS severity. Sleep duration was recognized as a mediating variable that supports the indirect effects.

Association of sleep traits with risk of hypertensive disorders of pregnancy: a mendelian randomization study

BACKGROUND

Unhealthy sleep patterns are common during pregnancy and have been associated with an increased risk of developing hypertensive disorders of pregnancy (HDPs) in observational studies. However, the causality underlying these associations remains uncertain. This study aimed to evaluate the potential causal association between seven sleep traits and the risk of HDPs using a two-sample Mendelian randomization study.

METHODS

Genome-wide association study (GWAS) summary statistics were obtained from the FinnGen consortium, UK Biobank, and other prominent consortia, with a focus on individuals of European ancestry. The primary analysis utilized an inverse-variance-weighted MR approach supplemented by sensitivity analyses to mitigate potential biases introduced by pleiotropy. Furthermore, a two-step MR framework was employed for mediation analyses.

RESULTS

The data analyzed included 200 000-500 000 individuals for each sleep trait, along with approximately 15 000 cases of HDPs. Genetically predicted excessive daytime sleepiness (EDS) exhibited a significant association with an increased risk of HDPs [odds ratio (OR) 2.96, 95% confidence interval (95% CI) 1.40-6.26], and the specific subtype of preeclampsia/eclampsia (OR 2.97, 95% CI 1.06-8.3). Similarly, genetically predicted obstructive sleep apnea (OSA) was associated with a higher risk of HDPs (OR 1.27, 95% CI 1.09-1.47). Sensitivity analysis validated the robustness of these associations. Mediation analysis showed that BMI mediated approximately 25% of the association between EDS and HDPs, while mediating up to approximately 60% of the association between OSA and the outcomes. No statistically significant associations were observed between other genetically predicted sleep traits, such as chronotype, daytime napping, sleep duration, insomnia, snoring, and the risk of HDPs.

CONCLUSION

Our findings suggest a causal association between two sleep disorders, EDS and OSA, and the risk of HDPs, with BMI acting as a crucial mediator. EDS and OSA demonstrate promise as potentially preventable risk factors for HDPs, and targeting BMI may represent an alternative treatment strategy to mitigate the adverse impact of sleep disorders.

Sleep duration and its association with constipation in patients with diabetes: The fukuoka diabetes registry

AIMS

Shorter and longer sleep durations are associated with adverse health consequences. However, available evidence on the association of sleep duration with constipation is limited, especially in patients with diabetes, who are at a high risk of both conditions. This study aimed to examine the association between sleep duration and constipation in patients with type 2 diabetes.

METHODS

A total of 4,826 patients with type 2 diabetes were classified into six groups according to sleep duration: <4.5, 4.5-5.4, 5.5-6.4, 6.5-7.4, 7.5-8.4, and ≥8.5 hours/day. The odds ratios for the presence of constipation, defined as a defecation frequency <3 times/week and/or laxative use, were calculated using a logistic regression model.

RESULTS

Shorter and longer sleep durations were associated with a higher likelihood of constipation than an intermediate duration (6.5-7.4 hours/day). This U-shaped association persisted after adjusting for confounding factors, including lifestyle behavior, measures of obesity and glycemic control, and comorbidities. Broadly identical findings were observed when decreased defecation frequency and laxative use were individually assessed.

CONCLUSIONS

This study shows a U-shaped association between sleep duration and constipation in patients with type 2 diabetes, and highlights the importance of assessing sleep duration in daily clinical practice.

Causal association of sleep traits with the risk of thyroid cancer: A mendelian randomization study

BACKGROUND

This study was to explore the causal associations of sleep traits including sleep duration, snoring, chronotype, sleep disorders, getting up in the morning, sleeplessness/insomnia and nap during day with the risk of thyroid cancer based on Mendelian randomization (MR) analysis.

METHOD

Summary single nucleotide polymorphism (SNP)-phenotype association data were obtained from published genome-wide association studies (GWASs) using the FinnGen and UK Biobank databases. A series of screening processes were performed to select qualified SNPs strongly related to exposure. We applied the inverse variance weighted (IVW), the Mendelian Randomization robust adjusted profile score (MR-RAPS), the Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO), and the Weighted Median to estimate the causal links between sleep traits and the risk of thyroid cancer. Odds ratio (OR) and 95% confidence interval (CI) were calculated.

RESULTS

The IVW results showed that getting up in the morning (OR = 0.055, 95%CI: 0.004-0.741) and napping during day (OR = 0.031, 95%CI: 0.002-0.462) were associated with decreased risk of thyroid cancer in the Italian population. A 1.30-h decrease of sleep duration was associated with 7.307-fold of thyroid cancer risk in the Finnish population (OR = 7.307, 95%CI: 1.642-32.519). Cronotype could decrease the risk of thyroid cancer in the Finnish population (OR = 0.282, 95%CI: 0.085-0.939). Sleep disorders increased the risk of thyroid cancer in the Finnish population (OR = 2.298, 95%CI: 1.194-4.422). The combined results revealed that sleep duration was correlated with increased risk of thyroid cancer (OR = 5.600, 95%CI: 1.458-21.486).

CONCLUSION

Decreased sleep duration was associated with increased risk of thyroid cancer, which indicated the importance of adequate sleep for the prevention of thyroid cancer.

Molecular-Level Dysregulation of Insulin Pathways and Inflammatory Processes in Peripheral Blood Mononuclear Cells by Circadian Misalignment

Circadian misalignment due to night work has been associated with an elevated risk for chronic diseases. We investigated the effects of circadian misalignment using shotgun protein profiling of peripheral blood mononuclear cells taken from healthy humans during a constant routine protocol, which was conducted immediately after participants had been subjected to a 3-day simulated night shift schedule or a 3-day simulated day shift schedule. By comparing proteomic profiles between the simulated shift conditions, we identified proteins and pathways that are associated with the effects of circadian misalignment and observed that insulin regulation pathways and inflammation-related proteins displayed markedly different temporal patterns after simulated night shift. Further, by integrating the proteomic profiles with previously assessed metabolomic profiles in a network-based approach, we found key associations between circadian dysregulation of protein-level pathways and metabolites of interest in the context of chronic metabolic diseases. Endogenous circadian rhythms in circulating glucose and insulin differed between the simulated shift conditions. Overall, our results suggest that circadian misalignment is associated with a tug of war between central clock mechanisms controlling insulin secretion and peripheral clock mechanisms regulating insulin sensitivity, which may lead to adverse long-term outcomes such as diabetes and obesity. Our study provides a molecular-level mechanism linking circadian misalignment and adverse long-term health consequences of night work.

Poor sleep quality and associated factors among healthcare professionals at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia

Background

Poor sleep quality is linked to physiological dysfunction, which increases the risk of obesity, cardiovascular disease, cognitive impairment, and other medical conditions. Despite the known health risks of sleep disturbances, literature is still scant regarding sleep quality and its associated factors among healthcare professionals in Ethiopia. Therefore, this study aimed to determine the prevalence of poor sleep quality and its associated factors among healthcare professionals at the University of Gondar Comprehensive Specialized Hospital.

Methods

An institution-based cross-sectional study was conducted at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia. A total of 418 healthcare professionals participated in the study. The study participants were chosen using the stratified random sampling method. Data were collected using a structured, self-administered questionnaire. The Pittsburgh Sleep Quality Index (PSQI) was used to assess the sleep quality of participants. Bi-variable and multivariable logistic regression models were used. p ≤ 0.05 was used to declare statistically significant variables.

Results

The mean age of the study participants was 30.7 years (SD ± 6.3). The overall prevalence of poor sleep quality was 58.9% [95% CI (54.2, 63.6%)]. Being female [adjusted odds ratio (AOR) = 1.9, 95% CI (1.2, 2.9)], being a shift worker [AOR = 5.7, 95% CI (2.3, 14.3), not performing regular exercise [AOR = 2.08 (1.2-3.6)], being a khat chewer [AOR = 3.1, 95% CI (1.2, 7.6)], and having depressive symptoms [AOR = 2.6, 95% CI (1.3, 6.8)] were significantly associated with higher odds of having poor sleep quality.

Conclusion

The prevalence of poor sleep quality among healthcare professionals was found to be high. As a result, we recommend that healthcare providers at the University of Gondar Comprehensive Specialized Hospital focus on early regular screening for sleep disturbances and pay special attention to shift work schedules and behaviors such as khat chewing, exercise, and depressive symptoms.

Effect of Atypical Sleep EEG Patterns on Weaning From Prolonged Mechanical Ventilation

BACKGROUND

Approximately one-third of acute ICU patients display atypical sleep patterns that cannot be interpreted by using standard EEG criteria for sleep. Atypical sleep patterns have been associated with poor weaning outcomes in acute ICUs.

RESEARCH QUESTION

Do patients being weaned from prolonged mechanical ventilation experience atypical sleep EEG patterns, and are these patterns linked with weaning outcomes?

STUDY DESIGN AND METHODS

EEG power spectral analysis during wakefulness and overnight polysomnogram were performed on alert, nondelirious patients at a long-term acute care facility.

RESULTS

Forty-four patients had been ventilated for a median duration of 38 days at the time of the polysomnogram study. Eleven patients (25%) exhibited atypical sleep EEG. During wakefulness, relative EEG power spectral analysis revealed higher relative delta power in patients with atypical sleep than in patients with usual sleep (53% vs 41%; P < .001) and a higher slow-to-fast power ratio during wakefulness: 4.39 vs 2.17 (P < .001). Patients with atypical sleep displayed more subsyndromal delirium (36% vs 6%; P = .027) and less rapid eye movement sleep (4% vs 11% total sleep time; P < .02). Weaning failure was more common in the atypical sleep group than in the usual sleep group: 91% vs 45% (P = .013).

INTERPRETATION

This study provides the first evidence that patients in a long-term acute care facility being weaned from prolonged ventilation exhibit atypical sleep EEG patterns that are associated with weaning failure. Patients with atypical sleep EEG patterns had higher rates of subsyndromal delirium and slowing of the wakeful EEG, suggesting that these two findings represent a biological signal for brain dysfunction.

Circadian desynchrony and glucose metabolism

The circadian timing system controls glucose metabolism in a time-of-day dependent manner. In mammals, the circadian timing system consists of the main central clock in the bilateral suprachiasmatic nucleus (SCN) of the anterior hypothalamus and subordinate clocks in peripheral tissues. The oscillations produced by these different clocks with a period of approximately 24-h are generated by the transcriptional-translational feedback loops of a set of core clock genes. Glucose homeostasis is one of the daily rhythms controlled by this circadian timing system. The central pacemaker in the SCN controls glucose homeostasis through its neural projections to hypothalamic hubs that are in control of feeding behavior and energy metabolism. Using hormones such as adrenal glucocorticoids and melatonin and the autonomic nervous system, the SCN modulates critical processes such as glucose production and insulin sensitivity. Peripheral clocks in tissues, such as the liver, muscle, and adipose tissue serve to enhance and sustain these SCN signals. In the optimal situation all these clocks are synchronized and aligned with behavior and the environmental light/dark cycle. A negative impact on glucose metabolism becomes apparent when the internal timing system becomes disturbed, also known as circadian desynchrony or circadian misalignment. Circadian desynchrony may occur at several levels, as the mistiming of light exposure or sleep will especially affect the central clock, whereas mistiming of food intake or physical activity will especially involve the peripheral clocks. In this review, we will summarize the literature investigating the impact of circadian desynchrony on glucose metabolism and how it may result in the development of insulin resistance. In addition, we will discuss potential strategies aimed at reinstating circadian synchrony to improve insulin sensitivity and contribute to the prevention of type 2 diabetes.

Insomnia and risk of mortality in older adults

Existing evidence linking insomnia to all-cause mortality in older individuals remains inconclusive. We conducted a retrospective study of a large cohort of veterans aged 65-80 years old identified from the Corporate Data Warehouse, a large data repository derived from the Veterans Health Administration integrated medical records. Veterans' enrollees with and without International Classification of Diseases, Ninth and Tenth Revision, codes corresponding to insomnia diagnosis between 1 January 2010 and 30 March 2019 were assessed for eligibility. The primary outcome was all-cause mortality. A total of 36,269 veterans, 9584 with insomnia and 26,685 without insomnia, were included in the analysis. Baseline mean (SD) age was 72.6 (4.2) years. During a mean follow-up of 6.0 (2.9) years of the propensity score matched sample, the mortality rate was 34.8 [95% confidence interval: 33.2-36.6] deaths per 1000 person-years among patients with insomnia compared with 27.8 [95% confidence interval: 26.6-29.1] among patients without insomnia. In a Cox proportional hazards model, insomnia was significantly associated with higher mortality (hazard ratio: 1.39; [95% confidence interval: 1.27-1.52]). Patients with insomnia also had a higher risk of non-fatal cardiovascular events (hazard ratio: 1.21; [95% confidence interval: 1.06-1.37]). Secondary stratified analyses by sex, race, ethnicity and hypertension showed no evidence of effect modification. A higher risk of mortality (hazard ratio: 1.51; [95% confidence interval: 1.33-1.71]) was observed when depression was present compared with absent (hazard ratio: 1.26; [95% confidence interval: 1.12-1.44]; p = 0.02). In this cohort study, insomnia was associated with increased risk-adjusted mortality and non-fatal cardiovascular events in older individuals.

Parents' perceptions of factors influencing sleep in pediatric intensive care units: A qualitative study

PURPOSE

The purpose of this study is to explore factors influencing sleep in pediatric intensive care units as perceived by parents of critically ill children.

DESIGN AND METHODS

This descriptive qualitative study used individual semistructured interviews. Parents were recruited through purposive sampling from two pediatric intensive care units at two locations in one university hospital in Norway. Ten parents were interviewed. The interviews were analyzed using a six-phase reflexive thematic analysis.

FINDINGS

The analysis produced 17 subthemes under four main themes: environmental factors in the pediatric intensive care unit disturb children's sleep, children need trust and safety to sleep, nurses' cooperation with parents influences children's sleep, and nurses' structuring of their practices is fundamental to sleep promotion.

CONCLUSION

The parents found that the environment disturbed their children's sleep, and environmental factors were easier to control in single rooms than in multibed rooms. Children slept better when they felt safe and trusted the nurses, and parents desired more cooperation in promoting sleep for their children, which may be an essential and overlooked part of sleep promotion. Nurses varied considerably in how they prioritized sleep and structured their practices to promote sleep.

PRACTICE IMPLICATIONS

Nurses should take parents' experiences into account to better promote sleep for patients. By limiting environmental disturbances, building relationships with children to make them feel safe, including parents in sleep promotion, and prioritizing sleep in their practices, nurses could improve sleep quality and limit the consequences of sleep disturbance.

Potential Therapeutic Targets in Obesity, Sleep Apnea, Diabetes, and Fatty Liver Disease

Obesity and metabolic syndrome affect the majority of the US population. Patients with obesity are at increased risk of developing type 2 diabetes (T2DM), obstructive sleep apnea (OSA), and metabolic dysfunction-associated steatotic liver disease (MASLD), each of which carry the risk of further complications if left untreated and lead to adverse outcomes. The rising prevalence of obesity and its comorbidities has led to increased mortality, decreased quality of life, and rising healthcare expenditures. This phenomenon has resulted in the intensive investigation of exciting therapies for obesity over the past decade, including more treatments that are still in the pipeline. In our present report, we aim to solidify the relationships among obesity, T2DM, OSA, and MASLD through a comprehensive review of current research. We also provide an overview of the surgical and pharmacologic treatment classes that target these relationships, namely bariatric surgery, the glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon receptor agonists.

Differences in sleep spindle wave density between patients with diabetes mellitus and matched controls: implications for sensing and regulation of peripheral blood glucose

Background

Brain waves during sleep are involved in sensing and regulating peripheral glucose level. Whether brain waves in patients with diabetes differ from those of healthy subjects is unknown. We examined the hypothesis that patients with diabetes have reduced sleep spindle waves, a form of brain wave implicated in periphery glucose regulation during sleep.

Methods

From a retrospective analysis of polysomnography (PSG) studies on patients who underwent sleep apnea evaluation, we identified 1,214 studies of patients with diabetes mellitus (>66% type 2) and included a sex- and age-matched control subject for each within the scope of our analysis. We similarly identified 376 patients with prediabetes and their matched controls. We extracted spindle characteristics from artifact-removed PSG electroencephalograms and other patient data from records. We used rank-based statistical methods to test hypotheses. We validated our finding on an external PSG dataset.

Results

Patients with diabetes mellitus exhibited on average about half the spindle density (median=0.38 spindles/min) during sleep as their matched control subjects (median=0.70 spindles/min) (P<2.2e-16). Compared to controls, spindle loss was more pronounced in female patients than in male patients in the frontal regions of the brain (P=0.04). Patients with prediabetes also exhibited signs of lower spindle density compared to matched controls (P=0.01-0.04).

Conclusions

Patients with diabetes have fewer spindle waves that are implicated in glucose regulation than matched controls during sleep. Besides offering a possible explanation for neurological complications from diabetes, our findings open the possibility that reversing/reducing spindle loss could improve the overall health of patients with diabetes mellitus.

Associations between sleep duration, sleep disturbance and cardiovascular disease biomarkers among adults in the United States

BACKGROUND

Sleep problems are associated with abnormal cardiovascular biomarkers and an increased risk of cardiovascular diseases (CVDs). However, studies investigating associations between sleep problems and CVD biomarkers have reported conflicting findings. This study examined the associations between sleep problems and CVD biomarkers in the United States.

METHODS

Data were from the National Health and Nutrition Examination Survey (NHANES) (2007-2018) and analyses were restricted to adults ≥ 20 years (n = 23,749). CVD biomarkers [C-reactive Protein (CRP), low-density lipoproteins, high-density lipoproteins (HDL), triglycerides, insulin, glycosylated hemoglobin (HbA1c), and fasting blood glucose] were categorized as abnormal or normal using standardized cut-off points. Sleep problems were assessed by sleep duration (short [≤ 6 h], long [≥ 9 h], and recommended [> 6 to < 9 h) and self-reported sleep disturbance (yes, no). Multivariable logistic regression models explored the associations between sleep duration, sleep disturbance, and CVD biomarkers adjusting for sociodemographic characteristics and lifestyle behaviors.

RESULTS

The mean sleep duration was 7.1 ± 1.5 h and 25.1% of participants reported sleep disturbances. Compared to participants with the recommended sleep duration, those with short sleep duration had higher odds of abnormal levels of HDL (adjusted odds ratio [aOR] = 1.20, 95% confidence interval [CI] = 1.05-1.39), CRP (aOR = 3.08, 95% CI = 1.18-8.05), HbA1c (aOR = 1.25, 95% CI = 1.05-1.49), and insulin (aOR = 1.24, 95% CI = 1.03-1.51). Long sleep duration was associated with increased odds of abnormal CRP (aOR = 6.12, 95% CI = 2.19-17.15), HbA1c (aOR = 1.54, 95% CI = 1.09-2.17), and blood glucose levels (aOR = 1.45, 95% CI = 1.07-1.95). Sleep disturbance predicted abnormal triglyceride (aOR = 1.18, 95% CI = 1.01-1.37) and blood glucose levels (aOR = 1.24, 95% CI = 1.04-1.49).

CONCLUSION

Short and long sleep durations were positively associated with abnormal CRP, HDL, HbA1c, blood glucose, and insulin levels, while sleep disturbance was associated with abnormal triglyceride and blood glucose levels. Since sleep is a modifiable factor, adopting healthy sleeping habits may create a balanced metabolism and reduce the risk of developing a CVD. Our study may provide insights into the relationship between sleep duration, sleep disturbance, and CVD risk.

Preventive noninvasive vagal nerve stimulation reduces insufficient sleep-induced depression by improving the autonomic nervous system

BACKGROUND

Depression is closely linked to an imbalance in the autonomic nervous system (ANS). However, the role of this imbalance in mediating the effects of sleep deprivation (SD) and vagus nerve stimulation (VNS) on emotional well-being is not fully understood.

METHODS

A population-based analysis was conducted to explore the relationship between sleep duration, depression scores, and heart rate variability (HRV). Additionally, the chronic SD mouse model was established to assess the impact of preventive transcutaneous auricular VNS (taVNS) on pathological and behavioral changes.

RESULTS

Our study found a significant link between sleep duration, depression severity, and HRV. Shorter sleep duration was associated with higher depression scores and lower RMSSD (a measure of HRV). In our rat model, insufficient sleep consistently impaired HRV. This effect was mitigated by taVNS, accompanied by corresponding changes in levels of IL-1β and IL-6, astrocyte and microglia activation, and tail suspension times.

CONCLUSIONS

Using VNS as a preventive treatment for depression-risk individuals with insufficient sleep shows promise. It not only broadens the potential applications of VNS but also sheds light on its mechanism-particularly its role in enhancing vagal nerve function and balancing the ANS, as evidenced by HRV measurements.

Salivary α-amylase as a marker of sleep disorders: A theoretical review

Sleep disorders are commonplace in our modern societies. Specialized hospital departments are generally overloaded, and sleep assessment is an expensive process in terms of equipment, human resources, and time. Biomarkers would usefully complement current measures in the screening and follow-up of sleep disorders and their daytime repercussions. Among salivary markers, a growing body of literature suggests that salivary α-amylase (sAA) may be a cross-species marker of sleep debt. However, there is no consensus as to the direction of variation in sAA with sleep disorders. Herein, after describing the mechanisms of sAA secretion and its relationship with stress, studies assessing the relationship between sAA and sleep parameters are reviewed. Finally, the influence of confounding factors is discussed, along with methodological considerations, to better understand the fluctuations in sAA and facilitate future studies in the field.

Sleep Characteristics are Associated with Risk of Treated Diabetes Among Postmenopausal Women

OBJECTIVE

The purpose of this study was to determine whether sleep characteristics are associated with incidence of treated diabetes in postmenopausal individuals.

METHODS

Postmenopausal participants ages 50-79 years reported sleep duration, sleep-disordered breathing, or insomnia at baseline and again in a subsample 3 years later. The primary outcome was self-reported new diagnosis of diabetes treated with oral drugs or insulin at any time after baseline. Multivariable Cox proportional hazards models were used.

RESULTS

In 135,964 participants followed for 18.1 (± 6.3) years, there was a nonlinear association between sleep duration and risk of treated diabetes. Participants sleeping ≤5 hours at baseline had a 21% increased risk of diabetes compared with those sleeping 7 hours (adjusted hazard ratio [aHR] 1.21; 95% confidence interval [CI], 1.00-1.47). Those who slept for ≥9 hours had a nonsignificant 6% increased risk of diabetes compared with those sleeping 7 hours (aHR 1.06; 95% CI, 0.97-1.16). Participants whose sleep duration had decreased at 3 years had a 9% (aHR 1.09; 95% CI, 1.02-1.16) higher risk of diabetes than participants with unchanged sleep duration. Participants who reported increased sleep duration at 3 years had a risk of diabetes (HR 1.01; 95% CI, 0.95-1.08) similar to those with no sleep duration change. Participants at high risk of sleep-disordered breathing at baseline had a 31% higher risk of diabetes than those without (aHR 1.31; 95% CI, 1.26-1.37). No association was found between self-reported insomnia score and diabetes risk.

CONCLUSIONS

Sleep-disordered breathing and short or long sleep duration were associated with higher diabetes risk in a postmenopausal population.

The association between blue light exposure and incidence of type 2 diabetes: A prospective study of UK biobank

BACKGROUND

Type 2 diabetes (T2D) is the most common type of diabetes. However, research on the relationship between blue light exposure and diabetes development is limited.

OBJECTIVE

The present study aimed to investigate the relationship between blue light exposure and T2D incidence and whether it is affected by sleep duration, physical activity, outdoor activity time, and genetic susceptibility.

METHODS

A total of 471,686 participants without diabetes were recruited from the UK Biobank cohort. T2D incidence was assessed using hospital inpatient records. Blue light exposure was calculated based on the time spent watching TV, using a computer, and playing computer games, which was determined using an online questionnaire. Cox proportional hazards regression models were used to assess the survival relationship between blue light exposure and T2D, as well as the potential modification effects.

RESULT

A total of 18,738 cases of T2D were documented during the median follow-up of 13.04 years. After adjusting for potential confounders, the participants with heavy blue light exposure had a greater risk of T2D compared to those with mild blue light exposure (hazard ratio (HR) = 1.17, 95% confidence interval (CI): 1.12-1.23). A significant association between blue light exposure and T2D risk was observed among the participants with heavy physical activity (HR = 1.39, 95%CI: 1.25-1.55), healthy sleep habits (HR = 1.23, 95%CI: 1.10-1.36), higher outdoor activity time (HR = 1.14, 95%CI: 1.07-1.22), or high genetic susceptibility (HR = 1.24, 95%CI: 1.14-1.35). However, this association became non-significant among the participants with low genetic susceptibility (HR = 1.05, 95%CI: 0.97-1.15).

CONCLUSION

The present study showed that blue light exposure is associated with a greater risk of T2D independent of classical T2D risk factors.

Sleep Quality in Team USA Olympic and Paralympic Athletes

Adequate sleep is crucial for elite athletes' recovery, performance readiness, and immune response. Establishing reference ranges for elite athletes enables appropriate contextualization for designing and targeting sleep interventions.

PURPOSE

To establish sleep-quality reference ranges for Olympic and Paralympic cohorts using the Pittsburgh Sleep Quality Index (PSQI) and explore differences based on sex and sport types.

METHODS

Team USA athletes (men = 805, women = 798) completed the PSQI as part of a health-history questionnaire. Descriptive statistics were used to create reference ranges and linear models, and χ2 test of independence determined differences in PSQI global and component scores between sex, games, season, and participation.

RESULTS

Six hundred thirty-two (39.43%) athletes reported poor sleep (PSQIGlobal ≥ 5). Men displayed later bedtimes (P = .006), better global PSQI scores, shorter sleep latency, less sleep disturbance, and less use of sleep medication than women (all P < .001). Winter Games participants had later bedtime (P = .036) and sleep offset time (P = .028) compared with Summer Games athletes. Team-sport athletes woke earlier than individual-sport athletes (P < .001). Individual-sport athletes were more likely to have low (P = .005) and mild (P = .045) risk for reduced sleep duration than team-sport athletes.

CONCLUSION

These data provide PSQI-specific reference ranges to identify groups at greatest risk for poor sleep, who may benefit most from targeted sleep interventions.

Association between weekend catch-up sleep and the risk of prediabetes and diabetes: A cross-sectional study using KNHANES

BACKGROUND

The objectives of this cross-sectional study were to explore the relationship between weekend catch-up sleep (WCUS) and the risk of prediabetes/diabetes and to assess how this risk varies based on WCUS duration, using a large population sample in South Korea.

METHODS

Data were sourced from the 2021 Korea National Health and Nutrition Examination Survey, involving 2472 subjects aged 30 years and above, employed, and not using blood glucose-lowering medications. Prediabetes/diabetes risk was examined based on the presence of WCUS. Participants were categorized into four groups by WCUS duration (< 1, ≥ 1 and < 2, ≥ 2 and < 3, and ≥ 3 h) to evaluate the prediabetes/diabetes risk across varying WCUS durations.

RESULTS

No significant difference in prediabetes/diabetes risk was observed between the WCUS and non-WCUS groups. In subgroup analysis, a WCUS duration of 1 to 2 h was related to a lower odds ratio of prediabetes (aOR = 0.618, 95% CI = 0.382-0.999), while 3 h or more was associated with a higher odds ratio of diabetes (aOR = 3.098, 95% CI = 1.561-6.149).

CONCLUSIONS

In individuals who experience insufficient sleep during weekdays and manage to achieve the optimal average sleep duration of 1 to 2 h of WCUS, WCUS was associated with improved blood glucose regulation. However, compensating for excessive weekday sleep deprivation with WCUS of 3 h or more was associated with impaired blood glucose regulation.

Fitness age outperforms body mass index in differentiating aging patterns and health risk profiles of healthy adults aged 51-80 years

Physical fitness has been extensively shown to strongly associate with general health status and major health risks. Here we tested the ability of a novel estimate of fitness age (FitAge) to differentiate aging trajectories.This study aimed at (1) testing the ability of FitAge to differentiate aging patterns among decelerated, normal, and accelerated agers in selected health domains, (2) estimating the risk for developing major health issues depending on the aging trajectory, and (3) comparing FitAge to body mass index (BMI) categorization in differentiating healthy from unhealthy aging patterns.A total of 176 volunteers participated in this cross-sectional study. Participants underwent clinical screening and a comprehensive assessment of body composition, nutritional and health-related status, cognitive functioning, and haematochemical analyses with routine tests, oxidative stress, and inflammation markers. Scores for major health risks were also computed.FitAge outperformed BMI in estimating major health risk scores and was able to differentiate decelerated from normal and accelerated agers for health risk profile and several physiological domains. Body composition, immune system activation, and inflammation markers emerged as those variables flagging the largest differences between decelerated and accelerated aging patterns.The novel estimate of biological aging can accurately differentiate both in women and men decelerated from accelerated agers in almost all the domains scrutinized. Overall, decelerated aging is linked to positively oriented features which associate with reduced risk of developing major health issues.The present findings have potential relevance and practical implications to identify individuals at higher risk of accelerated aging according to their FitAge estimated via simple and cost-effective motor tests.

The relationship between daytime napping and glycemic control in people with type 2 diabetes

Aim

To examine the association between napping characteristics and glycemic control in people with type 2 diabetes.

Design

This study used a cross-sectional design.

Methods

A convenience sample of people with type 2 diabetes (N=226) were included. Glycemic control was indicated by HbA1c which was measured by A1C Now®+. Napping characteristics including napping frequency, duration, timing, and type were measured by validated questionnaires. Other variables, such as insomnia, cognitive impairment, and depression were measured by the Insomnia Severity Index, Montreal Cognitive Assessment, and Patient Health Questionnaire-9, respectively. Multivariate linear regression analyses were performed.

Results

The sample consisted of 122 women (54.0%), with a median age of 67 years. Their median HbA1c was 6.8%. No significant relationship was found between napping frequency and HbA1c. Among nappers, after controlling for covariates, long napping duration (≥60 min) and morning napping were both associated with poorer glycemic control. Compared with appetitive napping, restorative napping was associated with better glycemic control.

Conclusion

Daytime napping (e.g., duration and type) is an important modifiable factor for glycemic control in people with type 2 diabetes. This study provides new insights into the relationship between napping and glucose management among people with diabetes.

Objective sleep characteristics and hypertension: a community-based cohort study

Objective

The link between sleep quality and hypertension risk is well-established. However, research on the specific dose-relationship between objective sleep characteristics and hypertension incidence remains limited. This study aims to explore the dose-relationship association between objective sleep characteristics and hypertension incidence.

Methods

A community-based prospective cohort study design was employed using data from the Sleep Heart Health Study (SHHS). A total of 2,460 individuals were included in the study, of which 780 had hypertension. Baseline personal characteristics and medical history were collected. Objective sleep characteristics were obtained through polysomnography (PSG). Multivariate logistic regression models were utilized for analysis. Restricted cubic splines (RCS) were used to examine dose-relationship associations.

Results

After adjusting for covariates, the percentage of total sleep duration in stage 2 (N2%) was positively associated with hypertension incidence, while the N3% was negatively associated with hypertension incidence Odds ratio (OR) = 1.009, 95% confidence interval (CI) [1.001, 1.018], P = 0.037; OR = 0.987, 95% CI: [0.979, 0.995], P = 0.028, respectively. For every 10% increase in N2 sleep, the risk of developing hypertension increases by 9%, while a 3% decrease in N3 sleep corresponds to a 0.1% increase in the incidence of hypertension. In the subgroup of non-depression, a positive association between N2% and hypertension was significant statistically (OR = 1.012, 95%CI, 1.002, 1.021, P = 0.013, Pinteraction = 0.013). RCS demonstrated that the risk of developing hypertension was lower when N2% ranged from 38% to 58% and rapidly increased thereafter (P = 0.002, non-linear P = 0.040). The lowest risk for hypertension incidence risk of N3% occurring at 25%, and a significant increase below 15% or above 40% (P = 0.001, non-linear P = 0.008).

Conclusions

There's a negative association between N3% and the incidence of hypertension, and a positive association between N2% and the incidence of hypertension, particularly among non-depression individuals. These associations exhibit strong non-linear dose-response relationships.

Association between gastrointestinal symptoms and insomnia in patients with type 2 diabetes: The KAMOGAWA-DM cohort study

AIMS/INTRODUCTION

Gastrointestinal disturbances and insomnia affect the quality of life of patients with diabetes. However, the relationship between gastrointestinal symptoms and insomnia in patients with diabetes has rarely been analyzed. Thus, aim of this study was to investigate the association between gastrointestinal symptoms and insomnia in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

This cross-sectional study of patients with type 2 diabetes was carried out from January 2014 to April 2022 using the database of the KAMOGAWA-DM cohort study. Patient data were collected using a self-administered questionnaire, and the Izumo Scale and the Athens Insomnia Scale were used to assess gastrointestinal symptoms and insomnia, respectively. Multivariate logistic regression analysis was carried out to determine the association between gastrointestinal symptoms and insomnia.

RESULTS

A total of 175 patients with type 2 diabetes were included in this study. Patients with insomnia had higher Izumo scores than those without insomnia (P < 0.0001). Izumo scale score was significantly associated with insomnia in patients with type 2 diabetes, even after adjustment for age, body mass index, systolic blood pressure, glycated hemoglobin level, neuropathy, insulin therapy and nocturia (odds ratio 1.10, 95% confidence interval [CI] 1.06-1.16). Each gastrointestinal symptom assessed using the Izumo scale was associated with insomnia. The odds ratios of heartburn, stomach pain, lethargy, constipation and diarrhea for insomnia were 1.32 (95% CI 1.13-1.55), 1.38 (95% CI 1.16-1.63), 1.33 (95% CI 1.13-1.56), 1.21 (95% CI 1.08-1.36) and 1.29 (95% CI 1.12-1.47), respectively.

CONCLUSIONS

Gastrointestinal symptoms are strongly associated with sleep disturbances in patients with type 2 diabetes.

Habitual Short Sleep Duration, Diet, and Development of Type 2 Diabetes in Adults

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 from the UK Biobank baseline investigation (2006-2010) were analyzed for this cohort study between May 1 and September 30, 2023. The association between sleep duration and healthy dietary patterns with the risk of T2D was investigated during a median (IQR) follow-up of 12.5 (11.8-13.2) years (end of follow-up, September 30, 2021).

Exposure

For the analysis, 247 867 participants were categorized into 4 sleep duration groups: normal (7-8 hours per day), mild short (6 hours per day), moderate short (5 hours per day), and extreme short (3-4 hours per day). Their dietary habits were evaluated based on population-specific consumption of red meat, processed meat, fruits, vegetables, and fish, resulting in a healthy diet score ranging from 0 (unhealthiest) to 5 (healthiest).

Main Outcomes and Measures

Cox proportional hazards regression analysis was used to calculate hazard ratios (HRs) and 95% CIs for the development of T2D across various sleep duration groups and healthy diet scores.

Results

The cohort comprised 247 867 participants with a mean [SD] age of 55.9 [8.1] years, of whom 52.3% were female. During the follow-up, 3.2% of participants were diagnosed with T2D based on hospital registry data. Cox regression analysis, adjusted for confounding variables, indicated a significant increase in the risk of T2D among participants with 5 hours or less of daily sleep. Individuals sleeping 5 hours per day exhibited a 1.16 adjusted HR (95% CI, 1.05-1.28), and individuals sleeping 3 to 4 hours per day exhibited a 1.41 adjusted HR (95% CI, 1.19-1.68) compared with individuals with normal sleep duration. Furthermore, individuals with the healthiest dietary patterns had a reduced risk of T2D (HR, 0.75 [95% CI, 0.63-0.88]). The association between short sleep duration and increased risk of T2D persisted even for individuals following a healthy diet, but there was no multiplicative interaction between sleep duration and healthy diet score.

Conclusions and Relevance

In this cohort study involving UK residents, habitual short sleep duration was associated with increased risk of developing T2D. This association persisted even among participants who maintained a healthy diet. To validate these findings, further longitudinal studies are needed, incorporating repeated measures of sleep (including objective assessments) and dietary habits.

The impact of dietary and sleep rhythms on blood pressure in children and adolescents: a cross-sectional study

Evidence about the relationship between meal and sleep time and CVD in children is scarce. The aims of this study were to describe the association between life rhythm patterns and blood pressure in children. This research was conducted among 5,608 children aged 6 to 15 years old in Chongqing and Sichuan provinces in 2021 and 2022. Dietary and sleep rhythms information was collected. The time of the first meal and last meal, and sleep time, were obtained. The mean age was 10.48 ± 2.24 years old, with 2958 (52.75%) male participants. The mean feeding window on weekdays was 11.69 h, 12.42 h, and 13.23 h for participants aged 6-7 years old, 8-12 years old and 13-15 years old, respectively. Weekday feeding window and last mealtime were positively correlated with blood pressure levels. And the changes in the feeding window between weekdays and weekends were significantly correlated with BP. Sleep duration and change in wake time were significantly correlated with SBP. Based on these results, this study identified the optimal combination of dietary and sleep rhythm interventions for children younger than 12 years of age and aged 12 and older, respectively. Disorder dietary and sleep rhythms disorders may correlate with elevated blood pressure levels, suggesting developing optimal dietary and sleep rhythm patterns could prevent the incidence of CVDs in children. The optimal dietary rhythm was defined by the indexes of breakfast time, dinner time and daily feeding window. As good meal patterns are defined as satisfied the following three items: for children younger than 12 years should have breakfast after 7:30 am; aged 12 years and over should have breakfast after 7 am; having dinner before 6 pm; daily feeding window less than 12.5 h. And less optimal dietary rhythm should satisfy any condition or eat dinner between 6 pm and 8 pm; and poor dietary rhythm should not satisfy any of the three criteria and eat dinner after 8 pm. Children with optimal dietary rhythm (in group A) had lower SBP (P < 0.001), DBP (P = 0.002) and MAP (P < 0.001) than those in group C.

The effect of chrono-nutritional manipulation of carbohydrate intake on sleep macrostructure: A randomized controlled trial

BACKGROUND & AIMS

Over the years, there is a rapid increase in the prevalence of inadequate sleep and its detrimental consequences. Yet, the impact of prolonged nutritional interventions on sleep optimization remains unexplored. To examine the effect of carbohydrate manipulation combined with exercise training on sleep macro-structure.

METHODS

Forty-two healthy, trained male volunteers were recruited for this study. The 4-week intervention consisted of three groups: i) Sleep Low-No Carbohydrates (SL-NCHO): participants consumed all their carbohydrate intake at regular intervals prior to evening training, ii) Sleep High-Low Glycemic Index (SH-LGI) and iii) Sleep High-High Glycemic Index (SH-HGI): Carbohydrate intake was spread throughout the day, both prior (60% of total CHO intake) and after evening training (40% of total CHO intake). The SH-LGI and SH-HGI groups differentiated by consuming either LGI or HGI foods in the evening, respectively. Alongside, participants performed a standardized exercise program combining resistance exercise and high-intensity interval training. Participants' sleep macro-structure was assessed with polysomnography, actigraphy, sleep diary, and sleep-wake questionnaires.

RESULTS

Objective assessments revealed a substantial time-effect on sleep initiation, duration, and continuity. After the intervention, sleep onset latency decreased (p < 0.001), sleep duration was prolonged (p = 0.006), sleep efficiency increased (p < 0.001), and wake after sleep onset decreased (p = 0.035). Sleep macroarchitecture did not significantly change, while the percentage of REM sleep stage to the total sleep time increased over time (p < 0.01). Consistent with the objective findings, subjects reported improved subjective sleep quality (p = 0.043) and reduced daytime sleepiness (p = 0.047).

CONCLUSION

The combination of a personalized dietary plan with exercise training enhances sleep initiation, sleep continuity, sleep duration, REM and N1 sleep stages, independently of carbohydrate type or timing. Lifestyle interventions should be investigated further to promote sleep quality and recovery.

REGISTRATION

The trial was registered at clinicaltrials.gov as NCT05464342.

Sleep disturbances in children and adolescents with type 1 diabetes mellitus: Prevalence, and relationship with diabetes management

OBJECTIVE

A decline in sleep quality and regularity has been reported in patients with type 1 diabetes mellitus (T1D) in many studies. However, research on medical-based sleep disorders in patients with T1D is limited. Diagnosing sleep disorders is crucial, as it negatively impacts academic performance, cardiovascular health, and cognitive functions among children as well as essential skills for effective diabetes management. Our objective was to assess sleep disturbances in patients diagnosed with T1D and explore whether these patients experience significantly more sleep disturbances compared to their healthy peers.

METHODS

This study, designed as a cross-sectional case-control investigation, involved a cohort of 250 participants (144 T1D, 106 control cases) aged 6-15 years. The Sleep Disturbance Scale for Children (SDCS) scores of the T1D group were compared with those of the control group. Furthermore, the study explored the correlation between clinical/biochemical parameters and SDCS scores within the T1D group.

RESULTS

The mean age of individuals in the T1D group was 10.27 ± 3.25 years, while the control group had a comparable mean age of 10.48 ± 3.5 years (P = 0.303). Within the T1D group, the median duration of diabetes was 5 (1-15) years, and the median glycosylated hemoglobin A1c (HbA1c) level for the past one year was 8.4 %. Although there was no significant difference in total SDSC scores between the T1D and control groups, both groups exhibited average scores that remained close to the threshold indicative of sleep disturbances (>39). Notably, individuals with total SDSC scores surpassing 39 were identified at rates of 48.6 % in the T1D group and 47.6 % in the control group, respectively. Furthermore, disorders of arousal nightmares (DA) were more prevalent in T1D patients compared to their healthy peers (P = 0.049). Additionally, HbA1c showed a positive correlation with scores for disorders of excessive somnolence (DOES) and total scores (P < 0.001, R = 0.368; P = 0.003, R = 0.243).

CONCLUSION

Our study found that the prevalence of sleep disturbances among children and adolescents with T1D was not significantly higher than that observed in their healthy peers. Nevertheless, it is crucial to note that a notable portion, 48.6 % of T1D cases and 47.6 % of healthy cases, displayed sleep disturbances based on SDSC scores. To optimize diabetes management and proactively address potential challenges, incorporating routine screening for sleep disturbances in the monitoring of T1D patients can yield valuable benefits.

Trends in the multiple prescriptions of hypnotic drugs in a university outpatient in Japan

AIMS

In Japan, the daily dosage of hypnotic drugs for insomnia treatment is increasing year by year, and over-dependence on treatment with hypnotic drugs is a major problem. This study aimed to examine the factors related to the elimination of prescriptions of three or more hypnotic drugs within 1 year in our clinic.

METHODS

We conducted two surveys. Survey ① assessed the frequency of prescriptions of three or more hypnotic drugs by retrospectively reviewing the medical records of all patients who visited general and psychiatric outpatient clinics from January 2013 to March 2019. Survey ② assessed changes in prescriptions of hypnotic and psychotropic drugs within the subsequent year by retrospectively reviewing the medical records of all patients prescribed three or more hypnotic drugs who visited neuropsychiatric outpatient clinics multiple times between April 2013 and March 2019.

RESULTS

The frequency of prescribing three or more hypnotic drugs was six to nine times higher in psychiatry than in other departments. Flunitrazepam and brotizolam were the most common drugs prescribed and had the second lowest discontinuation rate after zolpidem. Conversely, eszopiclone, zopiclone, and suvorexant had the highest discontinuation rates. The success factors for drug reduction were age (odds ratio [OR]: 0.97, p < 0.0037), trazodone addition (OR: 12.86, p < 0.0194) and number of years of psychiatric experience.

CONCLUSIONS

The characteristics and success factors in relation to drug reduction in patients with multiple prescriptions of hypnotic drugs identified in this study may contribute to solving the problem of multiple prescriptions of hypnotic drugs.

Association between poor sleep quality and locomotive syndrome in middle-aged and older women: A community-based, cross-sectional study

OBJECTIVE

Poor sleep quality, such as nocturnal arousal and sleep inefficiency, is associated with frailty and sarcopenia. Herein, we evaluated the relationship between poor sleep quality and locomotive syndrome (LS), a motor organ dysfunction common among community-dwelling middle-aged and older women.

METHODS

Participants comprised 2246 Japanese middle-aged and older women. LS was classified into stages LS-1, LS-2, and LS-3 (from least to most severe) according to the results of the stand-up test, two-step test, and 25-question Geriatric Locomotive Function Scale. Sleep quality was assessed using the Pittsburgh Sleep Quality Index.

RESULTS

The Pittsburgh Sleep Quality Index scores were significantly higher in the LS group than that in the non-LS group (P < .001). Multivariate logistic regression analyses adjusted for potential confounders identified poor sleep quality as an independent factor of LS (odds ratio 1.59 [95% confidence interval 1.30-1.93], P < .001). Similar results were observed in the sensitivity analysis in postmenopausal women. LS and trouble sleeping because of pain showed stepwise association in all LS stages.

CONCLUSIONS

Poor sleep quality was independently associated with LS among community-dwelling middle-aged and older women. As the stage of LS progressed, the proportion of women with poor sleep quality increased significantly.

Sleep, Diet Quality, and Lipid Profile Assessment in NCAA Division I Acrobatics and Tumbling Student-Athletes: A Cross-Sectional Study

OBJECTIVE

Acrobatics and Tumbling (A&T), an emerging National Collegiate Athletics Association (NCAA) sport, involves athletes with rigorous training backgrounds, usually extending from youth through early adulthood. This study examines the sleep health, diet quality, and lipid profile of A&T athletes clustered by their performance position.

METHODS

Forty-two A&T athletes, clustered as tops (n = 19; age = 19.6 ± 1.0 years; body mass index [BMI] = 22.3 ± 1.7 kg/m2) and bases (n = 23; age = 19.6 ± 1.3 years; BMI = 25.7 ± 2.5 kg/m2), completed preseason sleep and diet quality (Rapid Eating Assessment for Participants-Shortened [REAP-S]) surveys. Fasting blood samples were collected for lipid analysis. Body composition was assessed via dual-energy X-ray absorptiometry.

RESULTS

Most athletes (71.4%; base n = 14, top n = 16) reported insufficient sleep (≤7 hours) and "good" sleep quality (90.4%, n = 38; base n = 18, top n = 20). Average REAP-S score was 29.24 ± 3.74. Approximately 31% (n = 13) displayed at least one undesirable lipid concentration according to medical guidelines for normal levels (total cholesterol [TC] < 200 mg/dL, triglycerides [TG] < 150 mg/dL, high-density lipoprotein cholesterol [HDL-C] > 40 mg/dL, low-density lipoprotein cholesterol [LDL-C] < 130 mg/dL). Approximately 20% exhibited elevated TC (top n = 4, base n = 4), 12.5% had elevated TG (base n = 5), 2.5% showed low HDL-C (base n = 1), and 10% presented elevated LDL-C (top n = 2, base n = 2).

CONCLUSIONS

Most athletes experienced suboptimal sleep (≤7 hours/night) and 31% displayed at least one undesirable lipid concentration (elevated TC, TG, or LDL-C or reduced HDL-C). Tailoring interventions with sports dietitians is recommended, focused on increasing monounsaturated and polyunsaturated fat intake while reducing saturated fat consumption. These interventions could mitigate cardiovascular risks, improve recovery, and possibly enhance athletic performance.

Sleep timing behaviour, sleep duration and adherence to obesogenic dietary patterns from pre-school to school age: results from the Portuguese birth cohort Generation XXI

In an obesogenic environment, short sleeping may increase opportunistic eating. The timing of sleep might also influence the drive to eat. This study investigated the prospective association of sleep timing and duration with diet in 5286 children from the Portuguese birth cohort Generation XXI, evaluated at 4 and 7 years of age. At 4 years, sleep duration was categorised into ≤10 and >10 h. Four sleep timing categories were generated based on the median split for sleep-onset and -offset times: 'Early Sleep-Early Wake'; 'Early Sleep-Late Wake'; 'Late Sleep-Early Wake'; 'Late Sleep-Late Wake'. At 7 years, diet was obtained by a food frequency questionnaire and three dietary patterns were included: 'Healthier', 'Energy-Dense Foods (EDF)' and 'Snacking'. The Healthy Eating Index was used to evaluate diet quality. Multinomial logistic regression models and generalised linear models were performed. Children who had a late sleep, independently of the time of waking up, had higher odds of following the 'EDF' pattern, compared with the 'Healthier'. Boys who had late sleep and/or late wake had also higher odds of following the 'Snacking' pattern and had poorer diet quality. In both sexes, a late sleep or late wake were associated with a lower diet quality, compared to the group 'Early Sleep-Early Wake', and independently of nap behaviour. In boys, shorter sleep duration was associated with a poorer diet. In conclusion, pre-schoolers with late bedtimes or wake-up times have worse dietary patterns and poorer diet quality at the age of 7 years, which seems to be independent of sleep duration.

Causal Relationship Between Sleep Traits and Hypothalamic-Pituitary-Target Gland Axis Function: A Mendelian Randomization Study

Background

In recent years, multiple observational studies have confirmed the association between sleep traits and various human physiopathological states. However, the causal relationship between sleep traits and hypothalamic-pituitary-target gland axis (HPTGA) function remains unknown.

Methods

We obtained summary statistics on sleep traits (insomnia, chronotype, and sleep duration (long and short)) from the UK Biobank database. Data related to the HPTGA functions were obtained from the publicly available database. Subsequently, a two-sample Mendelian randomization (MR) analysis was performed to investigate the causal relationship between different sleep traits and the HPTGA function. Reverse MR analysis was conducted to examine the direction of causality.

Results

The MR analysis results suggested that chronotype is associated with decreased levels of six hormones in HPTGA. Sleep duration was causally associated with decreased levels of free thyroxine and progesterone. Both long and short sleep durations are detrimental to the secretion of prolactin-releasing peptide, somatostatin, and plasma cortisol, while short sleep duration can promote progesterone secretion. After gender stratification, we found that female reproductive function is more susceptible to the influence of unfavorable sleep traits.

Conclusion

Our MR analysis indicated a significant causal association between chronotype and suppressed gonadal function in healthy adult humans, with no apparent gender-specific effect. Extreme sleep durations were also found to be detrimental to the maintenance of normal HPTGA secretion function. Compared to males, gonadal function in the female cohort is more susceptible to extreme sleep habits. Subsequent observational studies are urgently needed to confirm the underlying mechanisms.

Firefighter Health: A Narrative Review of Occupational Threats and Countermeasures

Structural firefighters are responsible for protecting properties and saving lives during emergency operations. Despite efforts to prepare firefighters for these hazardous occupational demands, the unfortunate reality is that the incidence of health morbidities is increasing within the fire service. Specifically, cardiovascular disease, cancer, and mental health disorders are among the most documented morbidities in firefighters. Pubmed and Google Scholar search engines were used to identify peer-reviewed English language manuscripts that evaluated firefighters' occupational health threats, allostatic factors associated with their occurrence, and evidence-based strategies to mitigate their impact. This narrative review provides fire departments, practitioners, and researchers with evidence-based practices to enhance firefighters' health.

The association between Life's Essential 8 and all-cause, cancer and non-cancer mortality in US Cancer Survivors: A retrospective cohort study of NHANES

OBJECTIVE

To investigate Life's Essential 8 (LE8), a measure of cardiovascular health (CVH), associations with mortality outcomes in cancer survivors.

METHODS

A prospective cohort study included 1818 cancer survivors aged ≥20 years (weighted population: 13,204,583) from National Health and Nutrition Examination Survey (NHANES) 2005-2018. Linked to mortality data through 2019, LE8 data were gathered through self-reports and lab tests. An LE8 score of 80-100 is considered high CVH, 60-79 is moderate CVH, and 0-59 is low CVH. Multivariable Cox proportional hazards regression models were employed to evaluate the associations between LE8 and all-cause, cancer-specific and non-cancer mortality. Subsequently, subgroup analyses were conducted to assess the relationship between LE8 and mortality rates across various subgroups.

RESULTS

At baseline, there were 1818 cancer survivors. In a 15-year follow-up, 2548 deaths occurred: 601 from cancer, 647 from heart disease, and 1300 from other causes. Multivariable models showed high CVH associated with lower hazard ratios for all-cause, cancer-specific and non-cancer mortality vs. low CVH. Cumulative mortality rates increased during follow-up, more so in the low CVH group. Subgroup analysis revealed significant LE8 interactions with age or Poverty Income Ratio (PIR) for all-cause mortality. Additionally, significant interactions between LE8 and PIR were identified for cancer-specific and non-cancer mortality risks (P for interaction <0.05).

CONCLUSION

Among U.S. cancer survivors, higher CVH is independently linked to lower all-cause, cancer-specific, and non-cancer mortality risks. The new CVH definition shows promise as a primary prevention strategy to reduce mortality rates in U.S. cancer survivors.

The validity and reliability of the Persian version of the Athlete Sleep Screening Questionnaire

Background

Sleep as a biological phenomenon is effective in the performance and recovery of athletes. Questionnaires can be used as a cost-effective initial assessment tool for sleep. The Athlete Sleep Screening Questionnaire (ASSQ) demonstrated a clinically valid instrument for screening relevant sleep issues in athletic populations. Due to the lack of validated tools for adequate screening for sleep difficulties in the Iranian athlete population, the present study was conducted to evaluate the validity and reliability of the Persian version of the ASSQ.

Materials and Methods

The translation process was performed using instructions by Beaton et al. Content validity was assessed by a panel of experts. Exploratory and confirmatory factor analysis was performed for two 5-item sleep difficulty scores (SDS) and a 4-item chronotype score. Internal consistency based on Cronbach's alpha and McDonald's omega and stability reliability were used to evaluate reliability.

Results

The ASSQ achieved conceptual and semantic equivalence with the original scale. The item-level content validity index (I-CVI) of each item ranged from 0.87 to 1, and the averaging scale-level CVI/average was 0.95. In factor analysis, one factor for SDS and one factor for chronotype score were identified and confirmed. The internal consistency of the SDS scale (α =0.77, Ω =0.83) and chronotype (α =0.74, Ω =0.77) was acceptable. Stability reliability was confirmed for SDS scale (intra-class correlation [ICC] =0.87) and for chronotype (ICC = 0.83).

Conclusion

Persian ASSQ has acceptable psychometric measurement properties as a screening tool to assess sleep in Iranian athletes.

Nonrestorative Sleep and Type 2 Diabetes Incidence: the Aichi Workers' Cohort Study

BACKGROUND

The term "nonrestorative sleep (NRS)" refers to unrefreshed feeling at wake-up and is a domain of poor sleep quality. Previous researches have demonstrated that NRS is linked to a number of diseases and adverse health outcomes, but less is known regarding the link between NRS and diabetes, particularly in Japanese.

METHODS

We studied 3665 middle-aged male participants of the Aichi Workers' Cohort Study who were followed-up from 2002 to 2019. Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) of incident type 2 diabetes mellitus (T2DM) in relation to NRS adjusted for potential confounding variables.

RESULTS

During a median follow-up of 14.6 years, 421 type 2 diabetes cases were identified. Participants with NRS had a higher crude incidence rate of T2DM (11.2/1,000 person-years), compared to participants without NRS (9.3/1,000 person-years). In the fully adjusted model, individuals who reported having NRS had a significantly higher risk of developing T2DM (HR: 1.36, 95% CI: 1.10-1.67). The association was observed only in participants under 50 years old (HR: 1.82, 95% CI: 1.36-2.43), not in the older (50 years or older) participants (P for interaction =0.025). In contrast, stratified analyses by the presence of shift work, obesity or sleep duration showed similar associations in all the strata.

CONCLUSIONS

NRS was associated with higher risk of T2DM in middle-aged Japanese male workers independent of a variety of lifestyle factors and other sleep problems.

Associations of Training and Academic Stress with Sleep in Dual-Career Collegiate Badminton Athletes: A Preliminary Study

Introduction

Poor sleep negatively impacts cognitive and physical functioning and affects athletic and academic achievement. "Dual-career" athletes emphasize the pursuit of academic excellence along with athletic performance.

Purpose

The study aimed to assess sleep characteristics and sleep quality in dual-career collegiate badminton athletes. Furthermore, the study explored associations between training and academic stress and sleep, providing a theoretical basis for better training and sleep programs for dual-career athletes.

Participants and Methods

In this study, 15 dual-career collegiate badminton athletes were recruited, and 12 subjects (male n = 8, female n = 4, mean age 20.3 ± 1.7) completed the questionnaire. Repeated measurements were taken monthly in the spring semester from March to August 2021. The questionnaire assessed sleep quality and daytime sleepiness by the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Score (ESS). Moreover, we collected average training, study time per week, and monthly sports competitions and academic tests to quantify participants' training and academic stress.

Results

An average of 36.1% of dual-career athletes reported poor sleep and 25.0% had excessive daytime sleepiness. Overall, a significant positive correlation existed between PSQI scores and weekly study hours (r = 0.308, p = 0.009). Significant positive correlations were found between the four stressors and PSQI (August: r = 0.868, p < 0.001; July: r = 0.573, p = 0.026) or ESS scores (March: r = -0.678, p = 0.015; August: r = 0.598, p = 0.040) for specific months. Hierarchical linear modeling (HLM) analysis identified that lower study and training hours predict better sleep quality.

Conclusion

Dual-career collegiate badminton athletes had a higher prevalence of poor sleep and daytime sleepiness, and daytime sleepiness did not result in better sleep quality; study and training hours had the greatest effect on the sleep quality of dual-career collegiate badminton athletes.

Sleep extension and cardiometabolic health: what it is, possible mechanisms and real-world applications

Short sleep duration is associated with heightened cardiometabolic disease risk and has reached epidemic proportions among children, adolescents and adults. Potential mechanisms underlying this association are complex and multifaceted, including disturbances in circadian timing, food intake and appetitive hormones, brain regions linked to control of hedonic eating, physical activity, an altered microbiome and impaired insulin sensitivity. Sleep extension, or increasing total sleep duration, is an emerging and ecologically relevant intervention with significant potential to advance our understanding of the mechanisms underlying the association between short sleep duration and the risk of cardiometabolic disease. If effective, sleep extension interventions have potential to improve cardiometabolic health across the lifespan. Existing data show that sleep extension is feasible and might have potential cardiometabolic health benefits, although there are limitations that the field must overcome. Notably, most existing studies are short term (2-8 weeks), use different sleep extension strategies, analyse a wide array of cardiometabolic health outcomes in different populations and, frequently, lack adequate statistical power, thus limiting robust scientific conclusions. Overcoming these limitations will require fully powered, randomized studies conducted in people with habitual short sleep duration and existing cardiometabolic risk factors. Additionally, randomized controlled trials comparing different sleep extension strategies are essential to determine the most effective interventions. Ongoing and future research should focus on elucidating the potential cardiometabolic health benefits of sleep extension. Such studies have high potential to generate crucial knowledge with potential to improve health and quality of life for those struggling with short sleep duration.

Quantile regression to explore association of sleep duration with depression among adults in NHANES and KNHANES

BACKGROUND

Sleep duration has been associated with depression. However, mean regression, such as linear regression or logistic regression, may not capture relationships that occur mainly in the tails of outcome distribution. This study aimed to evaluate the associations between sleep duration and depression along the entire distribution of depression using quantile regression approach.

METHODS

This study included 55,954 adults aged 18 to 80 years from the National Health and Nutrition Examination Survey (N = 34,156) and the Korea National Health and Nutrition Examination Survey (N = 21,798). The coefficients corresponding to cross-group differences in PHQ-9 scores were estimated when comparing short or long sleep duration with normal sleep duration on deciles of PHQ-9 score distribution.

RESULTS

At lower quantiles, either short or long sleep duration was not associated with depression. At higher quantiles, the association of both short and long sleep duration with depression became much more pronounced. Compared with normal sleep duration, short and long sleep duration were associated with increases of 1.34 (95 % CI: 1.16, 1.51) and 0.28 (95 % CI: 0.04, 0.52) in PHQ-9 scores at the 50th quantile, while the corresponding increases were 3.27 (95 % CI: 2.83, 3.72) and 1.65 (95 % CI: 0.86, 2.45) at the 90th quantile, respectively. We also found that the magnitude of association between short sleep duration and depression was stronger among females and individuals with chronic diseases.

CONCLUSIONS

The beneficial effect of sufficient sleep in decreasing depression severity may be more evident among individuals with severe depression. Further studies could explore whether these heterogeneous associations can be generalized to populations with different characteristics.

Correlation analysis of heart rate variations and glucose fluctuations during sleep

OBJECTIVE

The body's glucose concentration is influenced by carbohydrate intake, insulin-induced carbohydrate reduction, and hepatic glycogen breakdown induced by stress hormones. This study investigated the potential of employing glucose fluctuations as a measure of stress by examining the relationship between heart rate variability (HRV) data and glucose levels during sleep in healthy subjects.

METHODS

In this cross-sectional study, a chest-worn electrocardiogram (ECG) and continuous glucose monitoring device (CGM) were respectively used to monitor the heart rate intervals and glucose fluctuations of five subjects (two males, three females) during sleep. A time-series correlation analysis was performed on the HRV data extracted from heart rate intervals and the corresponding glucose fluctuation data.

RESULTS

The time-series analysis of ECG and CGM data collected from subjects during sleep (n = 25 nights) revealed a moderate negative correlation between glucose levels and HRV, with a cross-correlation coefficient of r = -0.453.

CONCLUSION

Similar to HRV, changes in stress levels can be detected by observing glucose fluctuations, particularly during sleep when the impact of food intake can be eliminated. Our findings highlight a significant correlation between glucose levels and HRV, indicating that glucose fluctuations can be used as an indicator of autonomic nervous system activity in an exploratory study.