Sleep duration as a risk factor for incident type 2 diabetes in a multiethnic cohort

Brain-Derived Neurotrophic Factor is Associated with Self-Reported Quality of Sleep in Type 2 Diabetes Patients in Ghana

OBJECTIVE

Sleep disturbances are common in patients with type 2 diabetes (T2DM), and this exacerbates disease severity and results in poor quality of life. Brain-derived neurotrophic factor (BDNF) has been reported to mediate the association between T2DM and poor sleep health. The burden of self-reported poor sleep quality and duration in T2DM and their association with serum BDNF levels were investigated.

METHODS

In this case-control design, the Pittsburgh Sleep Quality Instrument was used to assess self-reported sleep quality and duration in 100 patients with T2DM and 80 nondiabetic controls. Sociodemographic data and medical history were collected from case notes and/or using a structured questionnaire. Fasting venous blood samples (5 mL) were collected to measure plasma lipid profile and serum BDNF levels.

RESULTS

patients with T2DM had low levels of BDNF, poor sleep quality (61.9% vs 27.5%, p<0.001), and shorter sleep duration (6.1±2.2 vs 6.9±1.1 h, p=0.003). T2DM status was associated with doubling the odds of poor sleep quality [OR (95%CI)=2.06 (1.07-6.43), p=0.039] and 1.6 times the odds of short sleep duration [1.63 (1.03-3.79), p=0.028]. Multivariable logistic regression analysis revealed no association between serum BDNF levels and sleep status. However, there was a negative biological interaction between T2DM and BDNF levels on poor sleep quality, resulting in 0.28 relative excess risk due to the interaction and a 12% attributable proportion due to the interaction.

CONCLUSION

In this study population, patients with T2DM had a high burden of self-reported poor quality of sleep and shorter sleep duration compared to the nondiabetic controls. T2DM interacts negatively with serum BDNF levels to affect sleep quality.

Effect of Dynamic Binaural Beats on Sleep Quality: A Proof-of-Concept Study with Questionnaire and Biosignals

Binaural beat (BB) has been investigated as a potential modality to enhance sleep quality. In this study, we introduce a new form of BB, referred to as dynamic BB (DBB), which incorporates dynamically changing carrier frequency differences between the left and right ears. Specifically, the carrier frequency of the right ear varied between 100 and 103 Hz over a period, while the left ear remained fixed at 100 Hz, yielding a frequency difference range of 0 to 3 Hz. The objective of this study was to examine the effect of DBB on sleep quality. Ten healthy participants were included in a cross-over design, where they experienced both DBB and a SHAM (absence of sound) condition across two consecutive nights, with polysomnography evaluation. DBB was administrated during pre-sleep initiation, sleep onset, and transition from rapid-eye-movement (REM) to non-REM stage. DBB significantly reduced sleep latency compared to the SHAM condition. Electrocardiogram analysis revealed that exposure to DBB led to diminished heart rate variability during the pre-sleep initiation and sleep onset periods, accompanied by a decrease in low frequency power of heart rate during the sleep onset period. DBB might be effective in improving the sleep quality, suggesting its possible application in insomnia treatments.

Association between napping and type 2 diabetes mellitus

As the incidence of type 2 diabetes mellitus (T2DM) is increasing rapidly and its consequences are severe, effective intervention and prevention, including sleep-related interventions, are urgently needed. As a component of sleep architecture, naps, alone or in combination with nocturnal sleep, may influence the onset and progression of T2DM. Overall, napping is associated with an increased risk of T2DM in women, especially in postmenopausal White women. Our study showed that napping >30 minutes (min) increased the risk of T2DM by 8-21%. In addition, non-optimal nighttime sleep increases T2DM risk, and this effect combines with the effect of napping. For nondiabetic patients, napping >30 min could increase the risks of high HbA1c levels and impaired fasting glucose (IFG), which would increase the risk of developing T2DM later on. For diabetic patients, prolonged napping may further impair glycemic control and increase the risk of developing diabetic complications (e.g., diabetic nephropathy) in the distant future. The following three mechanisms are suggested as interpretations for the association between napping and T2DM. First, napping >30 min increases the levels of important inflammatory factors, including interleukin 6 and C-reactive protein, elevating the risks of inflammation, associated adiposity and T2DM. Second, the interaction between postmenopausal hormonal changes and napping further increases insulin resistance. Third, prolonged napping may also affect melatonin secretion by interfering with nighttime sleep, leading to circadian rhythm disruption and further increasing the risk of T2DM. This review summarizes the existing evidence on the effect of napping on T2DM and provides detailed information for future T2DM intervention and prevention strategies that address napping.

The Association Between Race, Ethnicity and Sleep Quality and Duration: A National Health Interview Survey Study

BACKGROUND

Inadequate sleep duration and poor sleep quality are associated with adverse cardiovascular outcomes.

METHODS

Using data from the National Health Interview Survey, we compared self-reported sleep duration and quality among different groups: Whites, Chinese, Asian Indian, Filipino, and Other Asians. Outcome included Sleep duration (≥7 and <7 hours) and sleep quality (coded as a binary variable).

RESULTS

We included 155,203 participants. The overall prevalence of ≥7 hours of sleep was 69.5% and poor sleep quality was reported by 73.9%. Compared to Whites and Chinese, Filipinos, and Other Asians were less likely to get adequate sleep (≥7 hours). All 4 Asian groups were less likely to report poor sleep quality compared with White individuals, while Asian Indians reported poor sleep quality less frequently compared with Chinese individuals.

CONCLUSION

There are significant differences in sleep duration and quality between White and Asian groups, as well as within Asian subgroups. Further studies with disaggregated Asian subgroup data are needed to formally study these disparities.

Attitudes and beliefs about sleep health among a racially and ethnically diverse sample of overweight/obese adults

OBJECTIVES

To identify and compare how sleep-related attitudes and beliefs vary among racially and ethnically diverse adults with risk factors for cardio-metabolic disease.

METHODS

This exploratory qualitative study used online focus group discussions (N = 4 groups among 17 individuals) to collect information about sleep attitudes, beliefs, and practices following participation in the Mindfulness Intervention to Improve Sleep and Reduce Diabetes Risk Among a Diverse Sample in Atlanta (MINDS) study. A rapid analyses approach was used to identify shared themes related to attitudes and beliefs about sleep health and sleep practices across participants.

RESULTS

Participants on average were 31years old, 88% female, and identified as Black/African American (52.9%), White (17.7%), Asian (11.8%), and Hispanic (17.7%). Three themes related to attitudes and beliefs about sleep health were identified: prioritization of sleep to improve one's overall health, re-evaluating sleep needs, and interpersonal barriers to sleep. For Black/African American participants prioritizing sleep was coupled with a want to minimize stress as a long-term health promotion strategy, whereas individuals of other races/ethnicities were more focused on the immediate benefits of getting sufficient sleep. Individuals had reappraised their sleep needs and worked to improve their sleep hygiene accordingly, yet still experienced barriers to sleep. The most common barrier to sleep was sharing a sleep environment with someone who had conflicting sleep routines and practices.

CONCLUSION

The results of this study suggest perceived benefits of and barriers to sleep vary by race/ethnicity, thus future interventions should be culturally tailored to enhance effectiveness.

Noise Exposure and Cardiovascular Health

Noise is considered an environmental stressor adversely affecting well-being and quality of life, inter-individual communications, and attention and cognitive function and inducing emotional responses, corresponding to noise annoyance. In addition, noise exposure is associated with nonauditory effects including worsening mental health, cognitive impairments, and adverse birth outcomes, sleep disorders, and increased annoyance. An accumulating body of evidence has indicated that traffic noise is also associated with CVD, through multiple pathways. It has been shown that psychological stress and mental health disorders such as depression and anxiety have a negative impact on the development of cardiovascular diseases and outcomes. Likewise, reduced sleep quality and/or duration has been reported to increase sympathetic nervous system activity, which can predispose to conditions like hypertension and diabetes mellitus, known risk factors for CVD. Finally, there seems to be a disruption in the hypothalamic-pituitary-axis secondary to noise pollution that also results in an increased risk of CVD. The World Health Organization has estimated that the number of DALYs (disability-adjusted life-years) lost resulting from environmental noise in Western Europe ranges from 1 to 1.6 million, making noise the second major contributor to the burden of disease in Europe, only after air pollution. Thus, we sought to explore the relationship between noise pollution and risk of CVD.

Mitochondrial control of sleep

The function of sleep remains one of biology's biggest mysteries. A solution to this problem is likely to come from a better understanding of sleep homeostasis, and in particular of the cellular and molecular processes that sense sleep need and settle sleep debt. Here, we highlight recent work in the fruit fly showing that changes in the mitochondrial redox state of sleep-promoting neurons lie at the heart of a homeostatic sleep-regulatory mechanism. Since the function of homeostatically controlled behaviours is often linked to the regulated variable itself, these findings corroborate with the hypothesis that sleep serves a metabolic function.

Shift Work and Metabolic Syndrome Updates: A Systematic Review

Shift work can cause circadian cycles disturbances and misaligns the endogenous rhythms. The physiological variables are driven by the circadian system and, its misalignment, can impair the metabolic functions. Thus, the main objective of this study was to evaluate the metabolic alterations as a result of shift work and night work reported in articles published in the last 5 years, using the eligibility criteria both gender and indexed articles in English language. In order to execute this work, we perform a systematic review according to PRISMA guidelines and searched about Chronobiology Disorders and Night Work, both related to metabolism, in Medline, Lilacs, ScienceDirect and Cochrane. Cross-sectional, cohort and experimental studies with low risk of bias were included. We found a total of 132 articles, and, after the selection process, 16 articles remained to be analyzed. It was observed that shift work can cause circadian misalignment and, consequently, some metabolic parameters alterations such as an impaired glycemic control and insulin functioning, cortisol phase release, cholesterol fractions imbalance, changes in morphological indexes and melatonin secretion. There are some limitations, such as heterogenicity in used databases and the 5 years restriction period, because the effects of sleep disturbance may have been reported earlier. In conclusion, we suggest that shift work interferes with the sleep-wake cycle and eating patterns, which cause crucial physiological alterations that, together, can lead to metabolic syndrome.

Association between Sleep Duration and Incident Diabetes Mellitus in Healthy Subjects: A 14-Year Longitudinal Cohort Study

BACKGROUND

This study aimed to investigate whether sleep duration and/or quality are associated with incident diabetes mellitus (DM).

METHODS

A total of 8816 of 10,030 healthy participants were enrolled in a prospective cohort study. Sleep duration and quality questionnaires were completed. Sleep quality was assessed using the Epworth Sleepiness Scale (ESS), which measures excessive daytime sleepiness in individuals.

RESULTS

During the 14-year follow-up period, 18% (1630/8816) were diagnosed with DM. A U-shaped relationship was observed between sleep duration and incident DM, with the highest risk observed when sleep duration was ≥10 h/day (hazard ratios (HR) 1.65 [1.25-2.17]). This group exhibited decreased insulin glycogenic index, a marker of insulin secretory function, during the study period. Among study participants who slept less than 10 h/day, the risk of incident DM increased when the ESS score was >10.

CONCLUSIONS

We found that the association between sleep duration and incident DM was U-shaped; both short (≤5 h) and long (≥10 h) sleep durations were associated with an increased risk for the occurrence of incident DM. When sleep duration was 10 h or longer per day, there was a tendency to develop DM due to decreased insulin secretory function.

The Relationship between Sleep Duration and Metabolic Syndrome Severity Scores in Emerging Adults

BACKGROUND

Research suggests sleep duration can influence metabolic systems including glucose homeostasis, blood pressure, hormone regulation, nervous system activity, and total energy expenditure (TEE), all of which are related to cardiometabolic disease risk, even in young adults. The purpose of this study was to examine the relationship between sleep duration and metabolic syndrome severity scores (MSSS) in a sample of emerging adults (18-24 y/o).

METHODS

Data were collected between 2012 and 2021 from the College Health and Nutrition Assessment Survey, an ongoing, cross-sectional study conducted at a midsized northeastern university. Anthropometric, biochemical, and clinical measures were obtained following an overnight fast and used to assess the prevalence of metabolic syndrome (MetS). MetS severity scores (MSSS) were calculated using race- and sex-specific formulas. Sleep duration was calculated from the difference in self-reported bedtime and wake time acquired through an online survey. ANCOVA was used to examine the relationship between sleep duration and MetS severity score while adjusting for covariates (age, sex, BMI, physical activity level, smoking status, alcohol consumption, and academic major).

RESULTS

In the final sample (n = 3816), MetS (≥3 criteria) was present in 3.3% of students, while 15.4% of students presented with ≥2 MetS criteria. Mean MSSS was -0.65 ± 0.56, and the reported sleep duration was 8.2 ± 1.3 h/day. MSSS was higher among low sleepers (<7 h/day) and long sleepers (>9 h/day) compared to the reference sleepers (7-8 h/day) (-0.61 ± 0.02 and -0.63 ± 0.01 vs. -0.7 ± 0.02, respectively, p < 0.01).

CONCLUSIONS

Our findings suggest short (<7 h/day) and long (>9 h/day) sleep durations raise the risk of MetS in a sample of emerging adults. Further research is needed to elucidate the impact of improving sleep habits on future disease risk.

Sleep Duration and the Risk of Type 2 Diabetes: A Community-Based Cohort Study with a 16-Year Follow-up

BACKGRUOUND

We aimed to investigate the moderating effects of obesity, age, and sex on the association between sleep duration and the development of diabetes in Asians.

METHODS

We analyzed data from a cohort of the Korean Genome and Epidemiology Study conducted from 2001 to 2020. After excluding shift workers and those with diabetes at baseline, 7,407 participants were stratified into three groups according to sleep duration: ≤5 hours/night, >5 to 7 hours/night (reference), and >7 hours/night. The Cox proportional hazards analyses were used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for incident type 2 diabetes mellitus (T2DM). Subgroup analyses were performed according to obesity, age, and sex.

RESULTS

During 16 years of follow-up, 2,024 cases of T2DM were identified. Individuals who slept ≤5 h/night had a higher risk of incident diabetes than the reference group (HR, 1.17; 95% CI, 1.02 to 1.33). The subgroup analysis observed a valid interaction with sleep duration only for obesity. A higher risk of T2DM was observed in the ≤5 hours/night group in non-obese individuals, men, and those aged <60 years, and in the >7 hours/night group in obese individuals (HRs were 1.34 [95% CI, 1.11 to 1.61], 1.22 [95% CI, 1 to 1.49], and 1.18 [95% CI, 1.01 to 1.39], respectively).

CONCLUSION

This study confirmed the effect of sleep deprivation on the risk of T2DM throughout the 16-year follow-up period. This impact was confined to non-obese or young individuals and men. We observed a significant interaction between sleep duration and obesity.

Chrono-Nutrition: Circadian Rhythm and Personalized Nutrition

The human circadian system has a period of approximately 24 h and studies on the consequences of "chornodisruption" have greatly expanded. Lifestyle and environmental factors of modern societies (i.e., artificial lighting, jetlag, shift work, and around-the-clock access to energy-dense food) can induce disruptions of the circadian system and thereby adversely affect individual health. Growing evidence demonstrates a complex reciprocal relationship between metabolism and the circadian system, in which perturbations in one system affect the other one. From a nutritional genomics perspective, genetic variants in clock genes can both influence metabolic health and modify the individual response to diet. Moreover, an interplay between the circadian rhythm, gut microbiome, and epigenome has been demonstrated, with the diet in turn able to modulate this complex link suggesting a remarkable plasticity of the underlying mechanisms. In this view, the study of the impact of the timing of eating by matching elements from nutritional research with chrono-biology, that is, chrono-nutrition, could have significant implications for personalized nutrition in terms of reducing the prevalence and burden of chronic diseases. This review provides an overview of the current evidence on the interactions between the circadian system and nutrition, highlighting how this link could in turn influence the epigenome and microbiome. In addition, possible nutritional strategies to manage circadian-aligned feeding are suggested.

Do lifestyle factors and quality of life differ in people with metabolically healthy and unhealthy obesity?

BACKGROUND AND OBJECTIVES

Although obesity is typically associated with metabolic co-morbidities, some people with obesity do not develop metabolic abnormalities. We evaluated whether modifiable lifestyle factors (i.e., physical activity, dietary composition, and sleep characteristics) can help explain why some people with obesity are metabolically healthy (MHO) and whether metabolically unhealthy obesity (MUO) affects quality of life (QOL).

SUBJECTS/METHODS

Physical activity and sleep characteristics were assessed by using tri-axial accelerometers and dietary intake, sleep quality, and QOL were evaluated by using validated questionnaires in people stratified into three groups: (1) lean with normal glucose tolerance, plasma triglyceride (TG) concentration and intrahepatic TG (IHTG) content (metabolically healthy lean [MHL]; n = 20); (2) obesity and normal glucose tolerance, plasma TG concentration and IHTG content (MHO; n = 36); and (3) obesity with abnormal glucose metabolism and hepatic steatosis (MUO; n = 43).

RESULTS

People with MHO performed ~45-min more light-intensity physical activity/day than the MHL and MUO groups (P < 0.05). QOL, particularly the physical function domain, was higher in the MHO than the MUO group (P < 0.05). Although self-reported intake of starch, dairy, and cured meats were higher in the MUO than the MHO group (P < 0.02), the absolute differences were small and unlikely to have metabolic effects. No differences were found in sleep duration or quality between groups.

CONCLUSIONS

These data suggest physical activity, but not sleep or dietary intake, contribute to better metabolic health in people with MHO than those with MUO, and that QOL is lower in people with MUO than those with MHO.

The circadian system, sleep, and the health/disease balance: a conceptual review

The field of "circadian medicine" is a recent addition to chronobiology and sleep research efforts. It represents a logical step arising from the increasing insights into the circadian system and its interactions with life in urbanised societies; applying these insights to the health/disease balance at home and in the medical practice (outpatient) and clinic (inpatient). Despite its fast expansion and proliferating research efforts, circadian medicine lacks a formal framework to categorise the many observations describing interactions among the circadian system, sleep, and the health/disease balance. A good framework allows us to categorise observations and then assign them to one or more components with hypothesised interactions. Such assignments can lead to experiments that document causal (rather than correlational) relationships and move from describing observations to discovering mechanisms. This review details such a proposed formal framework for circadian medicine and will hopefully trigger discussion among our colleagues, so that the framework can be improved and expanded. As the basis of the framework for circadian medicine, we define "circadian health" and how it links to general health. We then define interactions among the circadian system, sleep, and the health/disease balance and put the framework into the context of the literature with examples from six domains of health/disease balance: fertility, cancer, immune system, mental health, cardiovascular, and metabolism.

The Effects of Insomnia and Sleep Loss on Cardiovascular Disease

Sleep loss has negative impacts on quality of life, mood, cognitive function and heath. Insomnia or difficulty sleeping is also a prevalent issue, affecting up to 35% of the population at some point in their lives. Insomnia is linked to poor mood, increased use of health care resources, and decreased quality of life as well as possible links to cardiovascular risk factors and disease. Studies have shown an increase in cortisol levels, decreased immunity, and increased markers of sympathetic activity in sleep-deprived healthy subjects and those with chronic insomnia. The literature also shows that subjective complaints consistent with chronic insomnia and shortened sleep time, both independently and in combination, can be associated with the development of diabetes, hypertension, and cardiovascular disease. In this article, we will explore the relationship and strength of association between insufficient sleep and insomnia with these health conditions.

Day-to-day variation in sleep duration is associated with increased all-cause mortality

STUDY OBJECTIVES

There is a paucity of data on the association between day-to-day variation in sleep pattern and all-cause mortality. We aimed to investigate whether day-to-day variation in sleep duration and onset of sleep are associated with cardiovascular and all-cause mortality.

METHODS

We used data belonging to 388 unique patients from the Midlife in the United States 2 Biomarker study (2004-2009). Information on sleep onset, duration, and sleep-wake cycles was collected for 7 consecutive days using the Actiwatch device. Sleep irregularity was assessed using mean and standard deviations in sleep duration and time of onset of sleep over 7 days. Cox proportional regression analysis and the Fine and Gray subdistribution method were used with all-cause and cardiovascular mortality, respectively.

RESULTS

Over a median of 8.6 years of follow-up, 37 patients died, including 10 deaths resulting from cardiovascular causes. There was no statistically significant increase in cardiovascular mortality with variation in sleep duration in the highest vs the lowest tertile (hazard ratio, 4.00; 0.45-35.48; P = .21). However, increased all-cause mortality was seen in the highest vs the lowest tertile (hazard ratio, 3.99; 1.33-11.94; P = .01). Multivariable model adjusting for confounders had higher all-cause mortality with increased sleep duration variation in the highest vs the lowest tertile: hazard ratio, 4.85; 1.52-15.49; P < .01).

CONCLUSIONS

Day-to-day variation in sleep duration is associated with increased all-cause mortality but not cardiovascular mortality after adjusting for mean sleep duration, inflammation, diabetes, age, body mass index, renal function, and blood pressure. Irregularity in the onset of sleep is not associated with all-cause mortality or cardiovascular mortality.

CITATION

Katamreddy A, Uppal D, Ramani G, et al. Day-to-day variation in sleep duration is associated with increased all-cause mortality. J Clin Sleep Med. 2022;18(3):921-926.

Mitochondria's role in sleep: Novel insights from sleep deprivation and restriction studies

OBJECTIVES/METHODS

The biology underlying sleep is not yet fully elucidated, but it is known to be complex and largely influenced by circadian rhythms. Compelling evidence supports of a link among circadian rhythms, sleep and metabolism, which suggests a role for mitochondria. These organelles play a significant role in energy metabolism via oxidative phosphorylation (OXPHOS) and several mitochondrial enzymes display circadian oscillations. However, the interplay between mitochondria and sleep is not as well-known. This review summarises human and animal studies that have examined the role of mitochondria in sleep. Literature searches were conducted using PubMed and Google Scholar.

RESULTS

Using various models of sleep deprivation, animal studies support the involvement of mitochondria in sleep via differential gene and protein expression patterns, OXPHOS enzyme activity, and morphology changes. Human studies are more limited but also show differences in OXPHOS enzyme activity and protein levels among individuals who have undergone sleep deprivation or suffer from different forms of insomnia.

CONCLUSIONS

Taken altogether, both types of study provide evidence for mitochondria's involvement in the sleep-wake cycle. We briefly discuss the potential clinical implications of these studies.

Relationship Between Diabetes-Related Complications and Sleep Complaints in Older Mexican Americans

INTRODUCTION/OBJECTIVE

The prevalence of Type 2 Diabetes Mellitus is increasing in the older American population, especially Mexican Americans. Sleep disorders are common in older adults with T2DM. This study examined the relationship between T2DM-related complications and sleep complaints in older Mexican Americans over 9 years of follow-up.

METHODS

Study included 310 participants aged 77 years or older with self-reported diabetes from the Hispanic Established Population for the Epidemiological Study of the Elderly (2007/08-2016).

RESULTS

Of the 310 participants, the mean age was 82.04 years. The cohort had significantly more females (69.03%) than males (30.97%). A substantial number of participants had trouble falling asleep (16.13%), waking up several times (36.45%), trouble staying asleep (15.16%), and feeling tired and worn out after waking up (12.90%). The percent of diabetes complications were 70.2% for circulation problems, 58.2% for eye disorders, 15.9% for kidney disease, and 4.4% for amputation. Participants who experienced sleep complaints for 15 or more days in a month were more likely to experience diabetic complications.

DISCUSSION

This study demonstrated a significant relationship between T2DM macro- and micro-vascular complications and increased risk of sleep disorders in older Mexican Americans.

Associations of midpoint of sleep and night sleep duration with type 2 diabetes mellitus in Chinese rural population: the Henan rural cohort study

Background

The study aimed to investigate the independent and combined effects of midpoint of sleep and night sleep duration on type 2 diabetes mellitus (T2DM) in areas with limited resources.

Methods

A total of 37,276 participants (14,456 men and 22,820 women) were derived from the Henan Rural Cohort Study. Sleep information was assessed based on the Pittsburgh Sleep Quality Index. Logistic regression models and restricted cubic splines were used to estimate the relationship of the midpoint of sleep and night sleep duration with T2DM.

Results

Of the 37,276 included participants, 3580 subjects suffered from T2DM. The mean midpoint of sleep among the Early, Intermediate and Late groups were 1:05 AM ±23 min, 1:56 AM ±14 min, and 2:57 AM ±34 min, respectively. Compared to the Intermediate group, adjusted odds ratios (ORs) and 95% confidence interval (CI) of T2DM were 1.13 (1.04–1.22) and 1.14 (1.03–1.26) in the Early group and the Late group. Adjusted OR (95% CI) for T2DM compared with the reference (7- h) was 1.28 (1.08–1.51) for longer (≥ 10 h) night sleep duration. The combination of late midpoint of sleep and night sleep duration (≥ 9 h) increased 38% (95% CI 10–74%) prevalence of T2DM. These associations were more obvious in women than men.

Conclusions

Late and early midpoint of sleep and long night sleep duration were all associated with higher prevalence of T2DM. Meanwhile, midpoint of sleep and night sleep duration might have combined effects on the prevalence of T2DM, which provided potential health implications for T2DM prevention, especially in rural women.

Trial registration

The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 2015-07-06.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10833-6.

Analysis of Evolution and Ethnic Diversity at Glucose-Associated SNPs of Circadian Clock-Related Loci with Cryptochrome 1, Cryptochrome 2, and Melatonin receptor 1B

Diabetes shows high heritability and, worldwide, causes significant health problems including cardiovascular disease and stroke. There is significant variation in the frequency of diabetes between different populations. Both Cryptochromes and Melatonin have a major role to regulate the circadian clock. Circadian clock failure causes metabolic dysfunctions including diabetes and obesity. Variations in the Cryptochrome 1, the Cryptochrome 2, and the Melatonin receptor 1B (MTNR1B) genes show associations with fasting glucose, and are also related to circadian clock. Here, we analyzed evidence for genetic selection and ethnic diversity at circadian clock- and glucose-related gene loci associated with Cryptochrome 1, Cryptochrome 2, and MTNR1B. We carried out a 3-step genetic method to investigate genetic selection at the Cryptochrome 1, Cryptochrome 2, and MTNR1B on four populations from the 1000 Genomes Project and HapMap. First we used F-statistics to quantify genetic population differences and find ethnic diversity. Then we applied a long-range haplotype test to detect significant extreme long haplotypes, and then the integrated haplotype score (iHS) to find genetic selection at Cryptochrome 1, Cryptochrome 2, and MTNR1B. We observed genetic population differences and ethnic diversity at one glucose-associated Cryptochrome 1 single-nucleotide polymorphism (SNP) (rs8192440), one glucose-associated Cryptochrome 2 SNP (rs11605924), and one glucose-associated MTNR1B SNP (rs10830963) by F-statistics. Both Cryptochrome 1 and MTNR1B also showed selection by the iHS. These observations show new evidence for evolution at Cryptochrome 1, Cryptochrome 2 and MTNR1B. Further investigation should continue to examine the evolution of circadian clock- and glucose-related genes.

Association of risk factors with type 2 diabetes: A systematic review

Diabetes is the leading cause of severe health complications and one of the top 10 causes of death worldwide. To date, diabetes has no cure, and therefore, it is necessary to take precautionary measures to avoid its occurrence. The main aim of this systematic review is to identify the majority of the risk factors for the incidence/prevalence of type 2 diabetes mellitus on one hand, and to give a critical analysis of the cohort/cross-sectional studies which examine the impact of the association of risk factors on diabetes. Consequently, we provide insights on risk factors whose interactions are major players in developing diabetes. We conclude with recommendations to allied health professionals, individuals and government institutions to support better diagnosis and prognosis of the disease.

Sleep duration and type 2 diabetes risk: A prospective study in a population-based Mexican American cohort

STUDY OBJECTIVES

The primary aim of the study was to estimate the effect of sleep duration on prospective type 2 diabetes (T2D) risk across demographic characteristics and follow-up periods, and test body mass index (BMI) as a mediator and moderator.

METHODS

Data included adults (M_age = 39.0 ± 12.7 years) born in the United States or Mexico recruited from 2001 to 2012 in a Mexican American cohort study conducted in Houston, TX (n = 15,779). Participants completed self-reported questionnaires at baseline related to health, health behaviors (sleep duration, physical activity, smoking, drinking), and sociocultural factors and were followed up annually.

RESULTS

Cox proportional hazard models estimated hazard ratios (HR) for the effect of sleep duration on T2D diagnosis at follow-up. Of the participants, 10.3% were diagnosed with T2D. Self-reported ≤5 hours of sleep, compared to 7-8 hours, at baseline predicted greater risk for T2D (HR = 1.32, P = .001), yet was no longer significant after adjusting for sociodemographic characteristics and BMI. Notably, those with BMI <25 kg/m² reporting ≤5 hours of sleep were at significant risk for T2D at 3 (HR = 4.13, P = .024) and 5-year follow-up (HR = 3.73, P = .008) compared to 7-8 hours. Obesity status accounted for 31.6% and 27.3% of the variance in the association between ≤5 and 6 hours of sleep and increased T2D risk, respectively.

CONCLUSIONS

Results highlighted the mediating and moderating role of BMI, and its effect on T2D risk at earlier follow-up among those without obesity. T2D prevention and control for Mexican American adults should consider the role of chronic sleep loss.

Association of sleep, screen time and physical activity with overweight and obesity in Mexico

PURPOSE

Approximately 70% of adults in Mexico are overweight or obese. Unhealthy lifestyle behaviors are also prevalent. We examined the association of three lifestyle behaviors with body mass index (BMI) categories in adults from Mexico.

METHODS

We used publicly available data from the ENSANUT 2016 survey (n = 6419). BMI was used to categorize participants. Differences in sleep duration, suffering from symptoms of insomnia, TV watching time, time in front of any screen, vigorous physical activity (yes vs no), moderate physical activity (> 30 min/day-yes vs. no) and walking (> 60 min/day-yes vs. no) were compared across BMI groups using adjusted linear and logistic regression analyses.

RESULTS

Thirty-nine percent of participants were overweight and 37% obese. Time in front of TV, in front of any screen, sleep duration and physical activity were significantly associated with overweight and obesity. Compared to normal weight participants, participants in the obese II category spend on average 0.60 h/day (95% CI 0.36-0.84, p = 0.001) and participants in the obese III category 0.54 h/day (95% CI 0.19-0.89, p < 0.001) more in front of any screen; participants in the obese II category reported 0.55 h/day less sleep (95% CI - 0.67 to - 0.43, p < 0.001); participants in the obese III category were less likely to engage in vigorous activity (OR = 0.60, 95% CI 0.43-0.84, p ≤ 0.003), or walking (OR = 0.65, 95% CI 0.49-0.88, p = 0.005).

CONCLUSION

Screen time, sleeping hours, and physical activity were associated with overweight and obesity. However, these associations were not consistent across all BMI categories. Assuming established causal connections, overweight individuals and individuals with obesity would benefit from reduced screen time and engaging in moderate/vigorous physical activity.

LEVEL OF EVIDENCE

Level III: observational case-control analytic study.

A Meta-Analysis of a Cohort Study on the Association between Sleep Duration and Type 2 Diabetes Mellitus

OBJECTIVE

To study the association between sleep duration and the incidence of type 2 diabetes mellitus (T2DM) and to provide a theoretical basis for the prevention of T2DM through a meta-analysis.

METHODS

PubMed, Web of Science, Scopus, Embase, Cochrane Library, ProQuest, CNKI, Wanfang, VIP, and SINOMED were searched from their inception until May 2020. All cohort studies on the relationship between sleep duration and T2DM in adults were included. According to the inclusion and exclusion criteria, two authors independently assessed the literature and extracted the data. Metaregression and publication bias were evaluated, and sensitivity and meta-analyses were conducted with RevMan 5.3.

RESULTS

A total of 17 studies were collected, involving 737002 adults. The incidence of T2DM was 4.73% in short sleep duration (SSD) (t ≤ 6 h), 4.39% in normal sleep duration (NSD) (6 h < t < 9 h), and 4.99% in long sleep duration (LSD) (t ≥ 9 h). The meta-analysis demonstrated that SSD increased the risk of T2DM compared with NSD (RR = 1.22, 95% CI: 1.15-1.29, P < 0.001), LSD increased the risk of T2DM compared with NSD (RR = 1.26, 95% CI: 1.15-1.39, P < 0.001), and the risk of T2DM has no significant difference between SSD and LSD (RR = 0.97, 95% CI: 0.89-1.05, P = 0.41). The sensitivity of each study was robust and the publication bias was weak.

CONCLUSION

SSD or LSD can increase the risk of T2DM.

Patterns and correlates of sleep duration in the Southern cohort community study

OBJECTIVE

To investigate whether race (African American (AA) and white) is associated with sleep duration among adults from low socioeconomic (SES) strata and whether SES status, lifestyle behaviors, or health conditions are associated with sleep duration within race-sex groups.

METHODS

This cross-sectional study includes 78,549 participants from the Southern Community Cohort Study (SCCS). Averaged daily sleep duration was assessed by weighted averages of self-reported sleep duration on weekdays and weekends. Adjusted odds ratios (ORs) of very short (<5 h/day), short (5-6 h/day), and long sleep (≥9 h/day) associated with pre-selected risk factors in each race-sex group were determined by multinomial logistic models.

RESULTS

The prevalence of very short and short sleep was similar among AAs (6.2% and 29.1%) and whites (6.5% and 29.1%). Long sleep was considerably more prevalent among AAs (19.3%) than whites (13.0%). Very short sleep was associated with lower education and family income, with stronger associations among whites. Higher physical activity levels significantly decreased odds for both very short (OR = 0.80) and long sleep (OR = 0.78). Smoking, alcohol use, and dietary intake were not associated with sleep duration. Regardless of race or sex, very short, short, and long sleep were significantly associated with self-reported health conditions, especially depression (ORs were 2.06, 1.33, and 1.38, respectively).

CONCLUSIONS

Sleep duration patterns differed between AAs and whites from the underrepresented SCCS population with low SES. Sleep duration was associated with several socioeconomic, health behaviors, and health conditions depending on race and sex.

Association between sleep duration and impaired fasting glucose according to work type in non-regular workers: data from the first and second year (2016, 2017) of the 7th Korean National Health and Nutrition Examination (KNHANE) (a cross-sectional study)

Background

We aimed to find the relationship between sleep duration and impaired fasting glucose according to working type in non-regular workers using the 2016 and 2017 Korean National Health And Nutrition Examination (KNHANE, 7th revision).

Method

In the 1st and 2nd year (2016, 2017) of the 7th KNHANE, 16,277 people participated. Minors were excluded because this study was intended for individuals aged 19 years and older. As this study was based on wage workers, unemployment, self-employed workers, employers, unpaid family workers, and those who have insufficient answers such as unknown or no response were excluded. Regular workers were excluded because this study was intended for non-regular workers. Finally, a total of 2,168 people were included in the survey, except those who had been diagnosed with diabetes, had a fasting blood glucose level of 126 mg/dL or higher, or taking hypoglycemic agents or receiving insulin injections. To find the relationship between sleep duration and impaired fasting glucose according to work type in non-regular workers, multiple logistic regression analysis was performed by adjusting the general and occupational characteristics after stratification according to work type. All statistical analyses were performed using the SPSS software (version 26.0; SPSS Inc., Chicago, IL, USA).

Results

In the case of insufficient sleep duration in irregular female workers, the odds ratio (OR) of impaired fasting glucose was statistically insignificant, but in the case of insufficient sleep duration in irregular male workers who have shift work, the odds ratio (OR) of impaired fasting glucose was significantly higher than that of sufficient sleep duration (Model 1, OR: 3.05, 95% confidence interval [CI]: 1.18–7.90; Model 2, OR: 2.81, 95% CI: 1.08–7.29).

Conclusions

Our findings demonstrate that insufficient sleep duration was associated with an increase in fasting blood glucose levels in non-regular male workers working shifts. This means that non-regular workers are in desperate need for adequate sleep and health care. We hope that our study will help improve the health of non-regular workers and more systematic and prospective follow-up studies will be conducted to further improve the health of non-regular workers.

Sleep Duration during Pregnancy using an Activity Tracking Device

Objective  The aim of this study was to describe sleep duration across gestation in women who wore an activity-tracking device (ATD) during pregnancy, and to study the association between sleep duration and adverse maternal and neonatal outcomes Study Design  Women ≥ 18 years old who owned a smartphone were approached to participate in 2016 to 2017. Participants received instructions to wear and sync an ATD daily. Steps, sedentary hours, and sleep duration were wirelessly transmitted via cellular technology. We measured sleep duration for the main episode of sleep and excluded sleep times < 120 minutes. Mixed models were used to assess the trajectory of mean weekly hours of sleep by gestational age. Secondary analyses evaluated differences in pregnancy outcomes between insufficient (< 7/24 hours) and sufficient sleep (≥ 7/24 hours) groups, based on mean hours of sleep within the first 7 days of ATD use. Results  The majority of 94 participants self-reported minority racial-ethnic status (33% non-Hispanic black and 51% Hispanic), had government insurance (83%), were nulliparous (61%), and had pre-pregnancy overweight or obesity (56%). The mean (standard deviation) duration of sleep was 7.2 ± 2.4 hours per 24 hours. In mixed models analyses, gestational age was statistically significantly associated with mean hours of sleep ( β = -0.02; 95% confidence interval: -0.04 to -0.01; p  < 0.001). Women who had < 7 hours of sleep had greater median daily steps compared with those who had ≥ 7 hours of sleep (median: 7,122; interquartile range [IQR]: 5,167-8,338 vs. median: 5,005; IQR: 4,115-7,059; p  < 0.01), but there were no significant differences in other outcomes (sedentary time, gestational weight gain, pregnancy associated hypertension, gestational diabetes, gestational age at delivery, cesarean delivery, or mean birthweight), p   > 0.05 for all comparisons. Conclusion  The mean sleep duration was 7.2 ± 2.4 hours among the 94 women in this cohort and decreased with advancing gestational age. Further research is required to evaluate sleep measurements with ATD in pregnant women and how sleep duration and quality is related to maternal and neonatal outcomes.

Sleep Characteristics and Measures of Glucose Metabolism in Blacks: The Jackson Heart Study

Background Characterizing associations of sleep characteristics with blood-glucose-level factors among blacks may clarify the underlying mechanisms of impaired glucose metabolism and help identify treatment targets to prevent diabetes mellitus in blacks. Methods and Results Cross-sectional analyses were conducted in 789 blacks who completed home sleep apnea testing and 7-day wrist actigraphy in 2012-2016. Sleep-disordered breathing measurements included respiratory event index associated with 4% oxygen desaturation and minimum oxygen saturation. Sleep patterns on actigraphy included fragmented sleep indices. Associations between sleep characteristics (8 exposures) and measures of glucose metabolism (3 outcomes) were determined using multivariable linear regression. Mean (SD) age of the participants was 63 (11) years; 581 (74%) were women; 198 (25%) were diabetes mellitus, and 158 (20%) were taking antihyperglycemic medication. After multivariable adjustment, including antihyperglycemic medication use, the betas (95% CI) for fasting glucose and hemoglobin A1c, respectively, for each SD higher level were 0.13 (0.02, 0.24) mmol/L and 1.11 (0.42, 1.79) mmol/mol for respiratory event index associated with 4% oxygen desaturation and 0.16 (0.05, 0.27) mmol/L and 0.77 (0.10, 1.43) mmol/mol for fragmented sleep indices. Among 589 participants without diabetes mellitus, the betas (95% CI) for homeostatic model assessment of insulin resistance for each SD higher level were 1.09 (1.03, 1.16) for respiratory event index associated with 4% oxygen desaturation, 0.90 (0.85, 0.96) for minimum oxygen saturation, and 1.07 (1.01, 1.13) for fragmented sleep indices. Conclusions Sleep-disordered breathing, overnight hypoxemia, and sleep fragmentation were associated with higher blood glucose levels among blacks.

Longitudinal Assessment of Sleep Trajectories during Early Childhood and Their Association with Obesity

Introduction: To identify longitudinal sleep trajectories in early childhood and examine the influence of sleep duration on obesity risk via BMI percentile (BMIp). Methods: Sleep, physical activity, and television viewing were measured in a cohort of 301 children, starting in 2001-2002, when children were 3 years and followed them through age 6. Nighttime sleep, daytime naps, and sleep duration were calculated. A series of latent growth curve models were used to estimate predictors of rate of change in sleep duration and BMIp overtime. A parallel process latent growth model examined the longitudinal relationship between sleep duration and BMIp simultaneously. Results: Most children (>80%) slept >10 hours per night across ages 3 to 6 years, despite the majority of children (>66%) having bedtimes after 9 pm. Sleep duration decreased on average by 0.22 (95% CI 0.20-0.24) hours each year of age (p < 0.001), while BMIp increased on average by 1.76 (95% CI 1.18-2.34) each year of age (p < 0.001). Baseline sleep duration predicted the BMIp slope factor, over and above strong effects of baseline BMIp. This indicated that greater sleep duration at baseline was predictive of decreased BMIp over time (unstandardized coefficient = -1.52 (95% CI 0.34-2.71, p = 0.012). Conclusions: Longer sleep duration at age 3 predicted decreased BMIp from ages 3 to 6. These findings indicate that focusing on sleep behaviors in children before age 3 may be a priority for pediatric providers with a goal of decreasing obesity risk.

Multiple sleep dimensions and type 2 diabetes risk among women in the Sister Study: differences by race/ethnicity

Objective

Poor sleep has been associated with type 2 diabetes. Since racial/ethnic minorities experience a disproportionately high prevalence of poor sleep and type 2 diabetes, we sought to determine the relationships between multiple sleep dimensions and incident type 2 diabetes and to investigate if these relationships vary by race/ethnicity.

Research design and methods

Prospective data were analyzed from the Sister Study, which enrolled 50 884 women from 2003 to 2009. Participants self-reported sleep duration, sleep latency, night awakenings, and napping at baseline, and a physician's diagnosis of type 2 diabetes at follow-up. Multivariable-adjusted HRs and 95% CIs were estimated using Cox proportional hazards models.

Results

Among the 39 071 eligible participants, 87% self-identified as white, 8% black and 5% Hispanic/Latina. The mean follow-up period was 8.5±2.1 years and 1785 type 2 diabetes cases were reported. The incidence rate per 1000 person-years was 5.4 for whites, 13.3 for blacks and 11.6 for Hispanics/Latinas. There was a positive but non-significant increased risk of type 2 diabetes among women who reported short sleep, latency >30 min and frequent night awakenings. In fully-adjusted models, frequent napping was associated with a 19% (HR 1.19, 95% CI 1.04 to 1.37) higher type 2 diabetes risk in the overall sample. Poor sleep among racial/ethnic minorities ranged from a 1.4-fold to a 3.2-fold higher type 2 diabetes risk than whites with recommended sleep.

Conclusions

Frequent napping was associated with higher type 2 diabetes risk. Racial/ethnic minorities with poor sleep had a higher type 2 diabetes risk than whites with recommended sleep.

Associations of sleep duration with cardiometabolic outcomes in American Indians and Alaska Natives and other race/ethnicities: results from the BRFSS

OBJECTIVES

This study assessed the associations between short and long sleep duration and prevalence of cardiometabolic outcomes in American Indians and Alaska Natives (AI/ANs) and compared these associations to those evident among other race/ethnicities.

METHODS

We analyzed data from the 2013-2014 Behavioral Risk Factor Surveillance System. In total, 14,536 AI/ANs, 729,962 non-Hispanic whites, 71,765 blacks, and 59,472 Hispanics were included. Logistic regressions were conducted to compute unadjusted and adjusted odds ratios (OR) for the associations of interest.

RESULTS

Among AI/ANs, 38.6% reported sleeping <7 hours per night (short sleepers) while 39.3% reported 8+ hours of sleep (long sleepers). After adjusting for age and gender, both short and long sleep durations were associated with higher odds of reporting diabetes, stroke, coronary heart disease and heart attack in almost all race/ethnic groups. After multiple adjustments, the sleep-diabetes association was more pronounced (OR = 1.71 and OR = 1.56 for short and long sleepers, respectively) among AI/ANs than other race/ethnicities.

CONCLUSIONS

Future studies are warranted to examine race/ethnic variability in the association between sleep duration and cardiometabolic outcomes.

Mindfulness and health behaviors in college students: The moderating role of sleep

Objective: To examine the moderating effects of subjective sleep quality (SSQ) and sleep duration on the relationships between mindfulness and health behaviors (i.e. nutrition and exercise) among undergraduate students. The unique influence of the five facets (i.e. factors) of mindfulness (i.e. observing, describing, acting with awareness, nonreactivity to inner experience and nonjudging of inner experience) on students' health behaviors was also explored. Participants: Three hundred fifty seven undergraduate students enrolled in U.S. colleges. Methods: Students completed an online survey. Hierarchical multiple regression analyses were conducted to determine whether SSQ moderated the relationship between mindfulness and nutrition behavior. Results: SSQ moderated the relationship between mindfulness and nutrition behavior. The observe facet of mindfulness was the most predictive of nutrition behavior, whereas the observe and describe facets were the most predictive of exercise behavior. Conclusions: Interventions that target mindfulness and sleep quality may help promote healthy eating and increased exercise engagement in college students.

Sleep duration in the United States 2003-2016: first signs of success in the fight against sleep deficiency?

Study Objectives

The high prevalence of chronic insufficient sleep in the population has been a concern due to the associated health and safety risks. We evaluated secular trends in sleep duration over the most recent 14-year period.

Methods

The American Time Use Survey, representative of US residents ≥15 years, was used to investigate trends in self-reported sleep duration and waking activities for the period 2003-2016 (N = 181335 respondents).

Results

Sleep duration increased across survey years both on weekdays (+1.40 min/year) and weekends (+0.83 min/year, both p < .0001, adjusted models). This trend was observed in students, employed respondents, and retirees, but not in those unemployed or not in the labor force. On workdays, the prevalence of short (≤7 hr), average (>7-9 hr), and long (>9 hr) sleep changed by -0.44% per year (p < .0001), -0.03% per year (p = .5515), and +0.48% per year (p < .0001), respectively. The change in sleep duration was predominantly explained by respondents retiring earlier in the evening. The percentage of respondents who watched TV or read before bed-two prominent waking activities competing with sleep-decreased over the same time period, suggesting that portions of the population are increasingly willing to trade time in leisure activities for more sleep. The results also suggest that increasing online opportunities to work, learn, bank, shop, and perform administrative tasks from home freed up time that likely contributed to increased sleep duration.

Conclusions

The findings indicate first successes in the fight against sleep deficiency. Public health consequences of the observed increase in the prevalence of long sleep remain unclear and warrant further investigation.

The Interlinked Rising Epidemic of Insufficient Sleep and Diabetes Mellitus

For healthy existence, humans need to spend one-third of their time sleeping. Any qualitative or quantitative disturbances in sleep would result in an increased prevalence of obesity, metabolic disorders, diabetes, cardiovascular diseases, and hypertension. The paper aims to highlight the growing global problem of insufficient sleep and its significant impact on the rising incidence of diabetes mellitus. An extensive literature search was done in all major databases for "insufficient sleep" and "Diabetes Mellitus" for this review. Shorter (<6 h) and longer (>9 h) durations of sleep have been adversely related to insulin resistance. Though the relation between insufficient sleep and diabetes mellitus is more or less understood, little is known about how oversleeping or hypersomnia (10⁻12 h) increases the risk of diabetes. The relationship between sleep disturbances and diabetes is dual-sided, as chronic sleep disturbances would elevate the risk of developing insulin resistance, while diabetes would worsen the quality of sleep. Both the qualitative and quantitative disturbances in sleep significantly increase the risk of developing diabetes, which is supported by numerous community-based and hospital-based epidemiological studies discussed in this review. Obstructive sleep apnea is one of the most common sleep disorders and is characterized by chronic intermittent hypoxia and increased sympathetic activity, thus leading to a higher prevalence of diabetes. Sleep therapy may serve as a low-cost method for fighting against the rising epidemic of diabetes.

Metabolic and cardiovascular consequences of shift work: The role of circadian disruption and sleep disturbances

Shift work, defined as work occurring outside typical daytime working hours, is associated with an increased risk of various non-communicable diseases, including diabetes and cardiovascular disease. Disruption of the internal circadian timing system and concomitant sleep disturbances is thought to play a critical role in the development of these health problems. Indeed, controlled laboratory studies have shown that short-term circadian misalignment and sleep restriction independently impair physiological processes, including insulin sensitivity, energy expenditure, immune function, blood pressure and cardiac modulation by the autonomous nervous system. If allowed to persist, these acute effects may lead to the development of cardiometabolic diseases in the long term. Here, we discuss the evidence for the contributions of circadian disruption and associated sleep disturbances to the risk of metabolic and cardiovascular health problems in shift workers. Improving the understanding of the physiological mechanisms affected by circadian misalignment and sleep disturbance will contribute to the development and implementation of strategies that prevent or mitigate the cardiometabolic impact of shift work.

Sleep duration and risk of incident stroke by age, sex, and race: The REGARDS study

OBJECTIVE

To investigate the association between reported sleep duration and incident stroke in a US cohort of black and white adults, and evaluate race, age, and sex as potential effect modifiers.

METHODS

From 2008 to 2010, 16,733 black and white adults, aged ≥45 years, without a history of stroke or sleep-disordered breathing from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, reported their habitual sleep duration (<6, 6.0-6.9, 7.0-8.9 [reference], ≥9 hours). Incident strokes were identified through biannual participant contact followed by physician adjudication of medical records. Cox proportional hazards analysis was conducted to calculate hazard ratios of interactions between sleep duration with race, age, sex, and 2-way combinations of these factors on incident stroke adjusting for stroke risk factors and sleep-disordered breathing risk.

RESULTS

The sample comprised 10.4% (n = 1,747) short sleepers (<6 hours) and 6.8% (n = 1,134) long sleepers (≥9 hours). Over an average 6.1 years follow-up, 460 strokes occurred. There were significant interactions between sleep duration and race (p = 0.018) and sleep duration and race-sex groups (p = 0.0023) in association with incident stroke. Short sleep duration was significantly associated with decreased risk for stroke among black participants (hazard ratio [HR] 0.49 [95% confidence interval (CI) 0.28-0.85]), particularly black men (HR 0.21 [95% CI 0.07-0.69]), whereas long sleep duration was significantly associated with increased risk for stroke among white men (HR 1.71 [95% CI 1.06-2.76]).

CONCLUSIONS

The association of sleep duration with incident stroke differs by race and sex, with short sleep duration among black men associated with decreased risk, whereas long sleep duration among white men associated with increased risk for stroke.

Short-Term Moderate Sleep Restriction Decreases Insulin Sensitivity in Young Healthy Adults

CONTEXT AND PURPOSE

The literature suggests that severe sleep loss of more than a few hours a night decreases glucose tolerance and insulin sensitivity. The aim of this study was to determine whether moderate sleep restriction had similar effects.

METHODS

Fifteen healthy non-obese (BMI=24.5±3.4 kg/m²) young adults (20.6±1.3 years) completed two 2-hour oral glucose tolerance tests (OGTT): one was after 3 days of time-in-bed restriction by 1-3 hours each night, and the other was after 3 days of ad libitum sleep. Glucose and insulin concentrations during OGTT, and fasting glucagon and cortisol concentrations were determined. The homeostasis model of insulin resistance (HOMA-IR), Matsuda index, and the quantitative insulin sensitivity check index (QUICKI) were calculated.

RESULTS

The total time-in-bed during the sleep restriction and the ad libitum phase was 5.98±0.76 and 7.98±0.54 hours/day, and total sleep time was 5.16±0.49 and 6.65±0.64 hours/day, respectively. Glucose concentrations before and 30, 60, 90, and 120 minutes following consumption of glucose and area under the curve were not different for the two OGTT (p > 0.10 for all). Insulin concentration at fasting and area under the curve during the OGTT were significantly higher (p = 0.034 and 0.038, respectively) following restricted sleep than following ad libitum sleep. Fasting glucagon concentration was also higher (p = 0.003). The HOMA-IR, Matsuda index, and QUICKI all suggested decreased insulin sensitivity following restricted sleep.

CONCLUSION

Short-term moderate sleep restriction reduced insulin sensitivity compared to ad libitum sleep in this group of healthy young adults.

The Epidemiology of Sleep and Diabetes

PURPOSE OF REVIEW

To provide an overview of the mechanistic and epidemiologic evidence linking sleep-related exposures, such as short sleep duration, obstructive sleep apnea, shift work, and insomnia, with type 2 diabetes risk in adults.

RECENT FINDINGS

Both poor sleep habits and sleep disorders are highly prevalent among adults with type 2 diabetes. In observational studies, short sleep duration, obstructive sleep apnea, shift work, and insomnia are all associated with higher risk of incident type 2 diabetes and may predict worse outcomes in those with existing diabetes. However, interventional studies addressing sleep abnormalities in populations with or at high risk for type 2 diabetes are scarce. Although common sleep abnormalities are associated with risk of incident type 2 diabetes and worse prognosis in those with established diabetes, there are few randomized trials evaluating the impact of sleep-focused interventions on diabetes, making it difficult to determine whether the relationship is causal.

Association of sleep disturbances with obesity, insulin resistance and the metabolic syndrome

Insufficient sleep, which has become endemic in recent years, has been variably associated with increased risk of obesity, disorders of glucose and insulin homeostasis, and the metabolic syndrome; to a lesser degree, so has excessive sleep. This review summarizes recent epidemiological and pathophysiological evidence linking sleep disturbances (primarily abnormalities of sleep duration) with obesity, insulin resistance, type 2 diabetes and the metabolic syndrome in children and adults.

Plasma Concentration of Caspase-8 Is Associated With Short Sleep Duration and the Risk of Incident Diabetes Mellitus

CONTEXT

The biological mechanism for the association between sleep duration and incident diabetes mellitus (DM) is unclear. Sleep duration and caspase-8, a marker of apoptotic activity, have both been implicated in β-cell function.

OBJECTIVE

To investigate the associations between sleep duration and plasma caspase-8 and incident DM, respectively.

DESIGN

Prospective cohort study.

SETTING

The Malmö Diet and Cancer (MDC) Study is a population-based, prospective study run in the city of Malmö, Sweden.

PARTICIPANTS

A total of 4023 individuals from the MDC Study aged 45 to 68 years at baseline without a history of prevalent DM and with information on habitual sleep duration.

MAIN OUTCOMES

Incident DM.

RESULTS

Mean follow-up time was 17.8 years. Sleep duration was the only behavioral variable significantly associated with plasma caspase-8. Plasma caspase-8 was significantly associated with incident DM per standard deviation of its transformed continuous form [hazard ratio (HR) = 1.24; 95% confidence interval (CI), 1.13 to 1.36] and when dichotomized into high (quartile 4) (HR = 1.44; 95% CI, 1.19 to 1.74) compared with low (quartiles 1 to 3) concentrations. Caspase-8 interacted with sleep duration; compared with individuals who had 7 to 8 hours of sleep and low plasma caspase-8, those with high plasma caspase-8 and sleep duration <6 hours (HR = 3.54; 95% CI, 2.12 to 5.90), 6 to 7 hours (HR = 1.81; 95% CI, 1.24 to 2.65), and 8 to 9 hours (HR = 1.54; 95% CI, 1.09 to 2.18) were at significantly increased risks of incident DM.

CONCLUSIONS

Sleep duration is associated with plasma caspase-8. Caspase-8 independently predicts DM years before disease onset and modifies the effect of sleep duration on incident DM. Future studies should investigate if change of sleep duration modifies plasma concentrations of caspase-8.

Sleep and Obesity

Rising global prevalence and incidence of obesity lead to increased cardiovascular-renal complications and cancers. Epidemiological studies reported a worldwide trend towards suboptimal sleep duration and poor sleep quality in parallel with this obesity epidemic. From rodents and human models, it is highly plausible that abnormalities in sleep, both quantity and quality, impact negatively on energy metabolism. While excess dietary intake and physical inactivity are the known drivers of the obesity epidemic, promotion of healthy sleep habits has emerged as a new target to combat obesity. In this light, present review focuses on the existing literature examining the relationship between sleep physiology and energy homeostasis. Notably, sleep dysregulation perturbs the metabolic milieu via alterations in hormones such as leptin and ghrelin, eating behavior, neuroendocrine and autonomic nervous systems. In addition, shift work and trans-meridian air travel may exert a negative influence on the hypothalamic-pituitary-adrenal axis and trigger circadian misalignment, leading to impaired glucose tolerance and increased fat accumulation. Amassing evidence has also suggested that uncoupling of the circadian clock can increase the risk of adverse metabolic health. Given the importance of sleep in maintaining energy homeostasis and that it is potentially modifiable, promoting good sleep hygiene may create new avenues for obesity prevention and treatment.

Incident diabetes mellitus may explain the association between sleep duration and incident coronary heart disease

AIMS/HYPOTHESIS

Sleep duration is a risk factor for incident diabetes mellitus and CHD. The primary aim of the present study was to investigate, in sex-specific analyses, the role of incident diabetes as the possible biological mechanism for the reported association between short/long sleep duration and incident CHD. Considering that diabetes is a major risk factor for CHD, we hypothesised that any association with sleep duration would not hold for cases of incident CHD occurring before incident diabetes ('non-diabetes CHD') but would hold true for cases of incident CHD following incident diabetes ('diabetes-CHD').

METHODS

A total of 6966 men and 9378 women aged 45-73 years from the Malmö Diet Cancer Study, a population-based, prospective cohort, who had answered questions on habitual sleep duration and did not have a history of prevalent diabetes or CHD were included in the analyses. Incident cases of diabetes and CHD were identified using national registers. Sex-specific Cox proportional hazards regression models were stratified by BMI and adjusted for known covariates of diabetes and CHD.

RESULTS

Mean follow-up times for incident diabetes (n = 1137/1016 [men/women]), incident CHD (n = 1170/578), non-diabetes CHD (n = 1016/501) and diabetes-CHD (n = 154/77) were 14.2-15.2 years for men, and 15.8-16.5 years for women. In men, short sleep duration (< 6 h) was associated with incident diabetes (HR 1.35, 95% CI 1.01, 1.80), CHD (HR 1.41, 95% CI 1.06, 1.89) and diabetes-CHD (HR 2.34, 95% CI 1.20, 4.55). Short sleep duration was not associated with incident non-diabetes CHD (HR 1.35, 95% CI 0.98, 1.87). Long sleep duration (≥ 9 h) was associated with incident diabetes (HR 1.37, 95% CI 1.03, 1.83), CHD (HR 1.33, 95% CI 1.01, 1.75) and diabetes-CHD (HR 2.10, 95% CI 1.11, 4.00). Long sleep duration was not associated with incident non-diabetes CHD (HR 1.33, 95% CI 0.98, 1.80). In women, short sleep duration was associated with incident diabetes (HR 1.53, 95% CI 1.16, 2.01), CHD (HR 1.46, 95% CI 1.03, 2.07) and diabetes-CHD (HR 2.88, 95% CI 1.37, 6.08). Short sleep duration was not associated with incident non-diabetes CHD (HR 1.29, 95% CI 0.86, 1.93).

CONCLUSIONS/INTERPRETATION

The associations between sleep duration and incident CHD directly reflect the associations between sleep duration and incident diabetes. Incident diabetes may thus be the explanatory mechanism for the association between short and long sleep duration and incident CHD.

Association between insomnia and coping style in Japanese patients with type 2 diabetes mellitus

PURPOSE

Insomnia, which is associated with type 2 diabetes mellitus (DM), results in a low quality of life, and several relationships exist between insomnia and coping style. Thus, we clarified the association between some coping styles and insomnia among Japanese type 2 DM patients.

SUBJECTS AND METHODS

The subjects included 503 type 2 DM patients (mean age 63.9±12.5 years). Sleep disturbance and personality traits were evaluated using the Japanese version of the Pittsburgh Sleep Quality Index and the Brief Scale for Coping Profile, respectively. Lifestyle factors, glycated hemoglobin A1c (HbA1c) levels, and the depression statuses of the patients were also included in the analyses.

RESULTS

Among the 503 subjects with type 2 DM, 141 (28.0%) subjects exhibited probable insomnia. After adjusting for confounders, being female, living alone, and using "avoidance and suppression" were significantly correlated with current insomnia. No other relationships were found between insomnia and HbA1c or lifestyle factors, such as smoking, drinking alcohol, and exercise frequency.

CONCLUSION

The prevalence of insomnia in individuals with type 2 DM was high, and the protective factors included some emotion-focused coping styles. Future prospective studies are required to confirm the therapeutic effects of behavioral interventions on insomnia in patients with type 2 DM.

Sleep During Pregnancy: The nuMoM2b Pregnancy and Sleep Duration and Continuity Study

Study Objectives

To characterize sleep duration, timing and continuity measures in pregnancy and their association with key demographic variables.

Methods

Multisite prospective cohort study. Women enrolled in the nuMoM2b study (nulliparous women with a singleton gestation) were recruited at the second study visit (16-21 weeks of gestation) to participate in the Sleep Duration and Continuity substudy. Women <18 years of age or with pregestational diabetes or chronic hypertension were excluded from participation. Women wore a wrist activity monitor and completed a sleep log for 7 consecutive days. Time in bed, sleep duration, fragmentation index, sleep efficiency, wake after sleep onset, and sleep midpoint were averaged across valid primary sleep periods for each participant.

Results

Valid data were available from 782 women with mean age of 27.3 (5.5) years. Median sleep duration was 7.4 hours. Approximately 27.9% of women had a sleep duration of <7 hours; 2.6% had a sleep duration of >9 hours. In multivariable models including age, race/ethnicity, body mass index, insurance status, and recent smoking history, sleep duration was significantly associated with race/ethnicity and insurance status, while time in bed was only associated with insurance status. Sleep continuity measures and sleep midpoint were significantly associated with all covariates in the model, with the exception of age for fragmentation index and smoking for wake after sleep onset.

Conclusions

Our results demonstrate the relationship between sleep and important demographic characteristics during pregnancy.

Sleep duration and progression to diabetes in people with prediabetes defined by HbA1c concentration

AIMS

To evaluate the association between sleep duration and the risk of progression to diabetes among people with prediabetes, defined by HbA_1c values.

METHODS

We conducted a cohort study in 17 983 adults who underwent health check-up examinations, including assessments of sleep duration and quality. Diabetes was defined as either HbA_1c ≥48 mmol/mol (6.5%), or the use of antidiabetic medication. Time-dependent proportional hazards models were used to evaluate the association between sleep duration and the risk of progression to diabetes.

RESULTS

During 31,582 person-years of follow-up, 664 incident cases of diabetes were identified; the incidence rate was 21.0 per 1000 person-years. The multivariate adjusted hazard ratios for progression to diabetes in people with sleep durations of ≤5, 6 and ≥8 h compared with 7 h were 1.68 (95% CI 1.30-2.16), 1.44 (95% CI 1.17-1.76) and 1.23 (95% CI 0.85-1.78), respectively (P for quadratic trend <0.001). This association was partially mediated by biomarkers of adiposity, fatty liver and insulin resistance.

CONCLUSION

In this large study in young and middle-aged adults with prediabetes, we found an association between short sleep duration and the risk of progression to diabetes. Our findings suggest that sufficient sleep duration is important for delaying or preventing the progression of prediabetes to diabetes.

Association Between Nonrestorative Sleep and Risk of Diabetes: A Cross-Sectional Study

Although insufficient sleep or poor sleep quality has been reported to be associated with the development of type 2 diabetes, the relation of type 2 diabetes with nonrestorative sleep (NRS), a subjective feeling, has been overlooked. We used a large-scale medical checkup database to investigate whether there is a cross-sectional association between NRS and type 2 diabetes risk in Japanese individuals. We extracted data for 14,476 individuals who were not receiving therapeutic drugs for diabetes. About 36.8% of individuals were identified as having NRS. In a multiple logistic regression analysis, NRS was significantly associated with the risk of developing diabetes. Thus, this line of research may have implications for diabetes prevention.