Self-reported daytime napping, daytime sleepiness, and other sleep phenotypes in the development of cardiometabolic diseases: a Mendelian randomization study

Investigating the impact of multidimensional sleep traits on cardiovascular diseases and the mediating role of depression

BACKGROUND

Observational studies have reported that sleep is associated with the risk of major depressive disorder (MDD) and cardiovascular diseases (CVDs). However, the causal relationships among various sleep traits remain contentious, and whether MDD mediates the impact of specific sleep traits on CVDs is unclear.

METHODS

We performed two-sample Mendelian randomisation analyses to explore whether insomnia, sleep time, daytime napping, daytime sleepiness, chronotype, snoring or obstructive sleep apnoea were causally associated with the risk of five CVDs, including coronary artery disease (CAD), myocardial infarction (MI), heart failure (HF), atrial fibrillation and stroke. Mediation analyses were performed to assess the proportion mediated by MDD.

RESULTS

Genetically predicted insomnia, short sleep, daytime napping and daytime sleepiness increased the risk of CVDs, with the OR ranging from 1.24 (95% CI 1.06 to 1.45) for insomnia on stroke to 1.55 (95% CI 1.28 to 1.89) for insomnia on MI. In contrast to short sleep, genetically predicted sleep duration decreased the risk of CAD (OR 0.88 (95% CI 0.80 to 0.97)), MI (OR 0.89 (95% CI 0.80 to 0.99)) and HF (OR 0.90 (95% CI 0.83 to 0.98)). However, we found no significant associations of long sleep, chronotype, snoring and obstructive sleep apnoea with increased risk for any CVD subtype. Additionally, the effect of insomnia was partially mediated by MDD for the risk of CAD (proportion mediated: 8.81% (95% CI 1.20% to 16.43%)), MI (9.17% (95% CI 1.71% to 16.63%)) and HF (14.46% (95% CI 3.48% to 25.45%)). Similarly, the effect of short sleep was partially mediated by MDD for the risk of CAD (8.92% (95% CI 0.87% to 16.97%)), MI (11.43% (95% CI 0.28% to 22.57%)) and HF (12.65% (95% CI 1.35% to 23.96%)). MDD also partially mediated the causal effects of insomnia on stroke, sleep duration on CAD, MI and HF, daytime napping on HF and daytime sleepiness on CAD.

CONCLUSIONS

Our study provides evidence that genetically predicted insomnia, short sleep, frequent daytime napping and sleepiness are associated with a higher risk of certain CVD subtypes, partly mediated by MDD.

Supplementation of essential amino acids suppresses age-associated sleep loss and sleep fragmentation but not loss of rhythm strength under yeast-restricted malnutrition in Drosophila

Sleep quality and quantity decrease with age, and sleep disturbance increases the risk of many age-associated diseases. There is a significant relationship between nutritional status and sleep outcomes, with malnutrition inducing poor sleep quality in older adults. However, it remains elusive whether, and if so how, nutritional supplementation prevents age-associated sleep problems. Here, we utilized Drosophila to investigate the effects of a malnutrition diet with restricted yeast, a primary protein source, and supplementation of 10 essential amino acids (EAAs) on sleep profiles during ageing. Compared with the standard diet containing 2.7% yeast, the malnutrition diet containing 0.27% yeast significantly decreased target of rapamycin (TOR) signalling and shortened the lifespan of male Canton-S flies. By contrast, age-associated sleep loss, sleep fragmentation and loss of rhythm strength were similarly observed under both diets. Supplementation of the malnutrition diet with EAAs in restricted yeast significantly ameliorated age-associated sleep loss and sleep fragmentation without altering loss of rhythm strength. It also rescued decreased TOR signalling activity but not the shortened lifespan, suggesting that the effects of EAAs on sleep integrity are independent of TOR activity and lifespan regulation. These results may help to develop dietary interventions that improve age-related sleep problems in humans.

Causal Effects of Sleep Traits on Angina Pectoris: Mediation by Cardiovascular Risk Factors

Purpose

Angina pectoris (AP) is a major factor in heightened risk of cardiac arrest and has been previously linked to sleep patterns. It remains unclear if sleep traits play a role in the onset of AP. Our study aims to declare the causality of sleep traits on AP by Mendelian randomization (MR) analyses.

Methods

Genome-wide association study (GWAS) data of sleep traits (sleep duration, insomnia, nap during day, chronotype, getting up in morning, narcolepsy, snoring) were obtained from the UK Biobank. The AP datasets came from an analysis containing samples from the UK biobank, FinnGen, and BioBank Japan. The GWAS data of cardiovascular risk factors (hypertension, smoking, hyperlipidemia, type 2 diabetes mellitus (T2DM)) came from the FinnGen. Two-sample MR analyses were carried out to gain a general map of sleep traits, risk factors and AP, then a multivariable MR was performed and the effect of each factor was calculated.

Results

We discovered a positive association between nap, narcolepsy, insomnia and stable angina pectoris (SAP), while getting up in morning associated with SAP negatively. Adequate sleep duration related to a reduced risk of SAP and unstable angina pectoris (UAP). Hypertension and T2DM acted as complete mediators in the relationship of nap and SAP, with an effect value of 1.267 (95% CI = 1.178-1.363, P < 0.01) and 1.059 (95% CI = 1.000-1.120, P < 0.05), and the mediating proportion was 27.7% (P < 0.05) and 7.70% (P = 0.102).

Conclusion

Our study found that nap, narcolepsy, and insomnia increased the risk of SAP, with hypertension and T2DM mediating the causal relationship between nap and SAP. Getting up in the morning reduced the risk of SAP, while longer sleep duration lowered the risk of SAP and UAP. More evidences are required to clarify the roles of sleep traits and risk factors in AP.

Causal Association of Sleep Traits with All-Cause and Cause-Specific Mortality: A Prospective Cohort and Mendelian Randomization Study

The study aimed to explore the association between different sleep traits and all-cause mortality as well as to validate causality in the association through mendelian randomization (MR). We analyzed 451,420 European ancestry participants from the UK Biobank. Multivariable-adjusted Cox proportional hazards model was conducted to evaluate the association between sleep traits and all-cause mortality. In MR analysis, the inverse variance weighting (IVW) method was applied as the primary analysis to investigate the causal association between sleep traits and mortality. During a median follow-up period of 12.68 years, 34,397 individuals died. Observational analyses showed the multivariate-adjusted hazard ratio (HR) and 95% confidence intervals (CIs) for short sleep, long sleep, early chronotype, daytime sleepiness, daytime napping, and insomnia with mortality, 1.246 (1.195, 1.298), 1.735 (1.643, 1.831), 0.931 (0.909, 0.953), 1.276 (1.212, 1.344), 1.299 (1.254, 1.346), and 1.117 (1.091, 1.142) (All p < 0.0001). Based on UK Biobank, MR analysis indicated the association between daytime napping and an increased risk of all-cause mortality (odd ratio [OR]: 1.219, 95% CI: 1.071-1.387, p = 0.003), which may be largely attributable to cancer disease mortality (OR: 1.188, 95% CI: 1.009-1.399, p = 0.039). We found no causal association between sleep duration, short sleep, long sleep, chronotype, daytime sleepiness, insomnia, and mortality risk. The causal associations between sleep traits and all-cause mortality risk were directionally replicated in FinnGen. Our findings suggest a potential causal association between daytime napping and increased risk of all-cause mortality in middle-aged and older persons. The finding could have important implications for evaluating daytime napping habits to decrease the risk of mortality.

Endothelial Dysfunction in Acute Myocardial Infarction: A Complex Association With Sleep Health, Traditional Cardiovascular Risk Factors and Prognostic Markers

BACKGROUND

Endothelial function (EndFx) is a core component of cardiovascular (CV) health and cardioprotection following acute myocardial infarction (AMI) treated with primary percutaneous coronary intervention (PCI).

HYPOTHESIS

AMI patients experience endothelial dysfunction (EndDys), associated with traditional CV risk factors and sleep patterns. EndFx may also predict short and mid-term outcomes.

METHODS

EndFx was assessed in 63 patients (56.2 ± 7.6 years) using the Endothelium Quality Index (EQI). Sleep quality and quantity were evaluated using objective (actigraphy) and subjective (Pittsburgh Sleep Quality Index questionnaire) measures. Cardiorespiratory fitness was quantified through the 6-min walking test. Cardiac function was assessed using the left ventricular ejection fraction.

RESULTS

Following AMI, patients tended to experience EndDys (EQI = 1.4 ± 0.7). A severe EndDys was observed in 23.8% of patients (n = 15), while a mild EndDys was present in 63.49% (n = 40). Furthermore, EndDys was significantly associated with traditional CV risk factors (i.e., low physical activity level [12.8%], age [-4.2%], and smoking [-0.7%]) (R2 adjusted = 0.50, p < 0.001). Patients with EndDys had poor sleep quality (p = 0.001) and sleep efficiency (p = 0.016) compared to healthy persons. Patients with severe EndDys exhibited lower cardiorespiratory fitness compared to those with healthy EndFx (p = 0.017). Furthermore, during a follow-up period (nearly 4 months) following PCI, major adverse cardiac events were observed in four patients with severe EndDys.

CONCLUSIONS

Our results emphasize the importance of adequate sleep and an active lifestyle, notably physical activity practice, as modifiable elements to enhance EndFx, which is regarded as a predictive tool following AMI. However, other factors remain to be elucidated as predictors of CV risk.

TRIAL REGISTRATION

The study protocol was registered in the Pan African Clinical Trial Registry under the trial ID: PACTR202208834230748.

The chronobiology of human heart failure: clinical implications and therapeutic opportunities

Circadian variation in cardiovascular and metabolic dynamics arises from interactions between intrinsic rhythms and extrinsic cues. By anticipating and accommodating adaptation to awakening and activity, their synthesis maintains homeostasis and maximizes efficiency, flexibility, and resilience. The dyssynchrony of cardiovascular load and energetic capacity arising from attenuation or loss of such rhythms is strongly associated with incident heart failure (HF). Once established, molecular, neurohormonal, and metabolic rhythms are frequently misaligned with each other and with extrinsic cycles, contributing to HF progression and adverse outcomes. Realignment of biological rhythms via lifestyle interventions, chronotherapy, and time-tailored autonomic modulation represents an appealing potential strategy for improving HF-related morbidity and mortality.

Dietary salt intake is not associated with risk of stroke: A Mendelian randomization study

Previous studies have demonstrated a correlation between dietary salt intake and stroke; however, there was a lack of conclusive evidence regarding a causal connection between them. We undertook a two-sample Mendelian randomization (MR) study to examine their potential association. The genome-wide data for dietary salt intake was sourced from genome-wide association study that involved 462,630 samples. Genetic instruments for stroke were also obtained from genome-wide association study, which included 446,696 samples. Both samples were from European. The inverse variance weighting was used as the main method in MR analysis. We also performed several complementary MR methods, including MR-Egger, position weighted median, simple model, and weighted model. Our results showed that there was no causal relationship between dietary salt intake and stroke, which was genetically determined (fixed-effects inverse variance weighted: odds ratio, 0.95; 95% confidence interval, 0.74-1.21; P  = .67). Neither Cochran Q test (P = .52) nor MR-Egger method (P = .48) found obvious heterogeneity; in addition, the MR pleiotropy residual sum and outliers global test (P = .52) and MR-Egger regression intercept (P = .74) also showed no pleiotropy. The result of our MR study showed that there was no direct causal relationship between dietary salt intake and stroke risk. More studies were required to further confirm the stability of this relationship and to trying applied the findings to the clinic.

Associations between insomnia and cardiovascular diseases: a meta-review and meta-analysis of observational and Mendelian randomization studies

STUDY OBJECTIVES

Observational studies suggest associations between insomnia and cardiovascular diseases (CVDs), but the causal mechanism remains unclear. We investigated the potential causal associations between insomnia and CVDs by a combined systematic meta-review and meta-analysis of observational and Mendelian randomization studies.

METHODS

We searched PubMed, Web of Science, and Embase for English-language articles from inception to July 11, 2023. Two reviewers independently screened the articles to minimize potential bias. We summarized the current evidence on the associations of insomnia with coronary artery disease, atrial fibrillation, heart failure, myocardial infarction, hypertension, and stroke risk by combining meta-analyses of observational and Mendelian randomization studies.

RESULTS

Four meta-analyses of observational studies and 9 Mendelian randomization studies were included in the final data analysis. A systematic meta-review of observational studies provided strong evidence that insomnia is an independent risk factor for many CVDs, including atrial fibrillation, myocardial infarction, and hypertension. A meta-analysis of Mendelian randomization studies revealed that insomnia may be potentially causally related to coronary artery disease (odds ratio [OR] = 1.14, 95% confidence interval [CI] = 1.10-1.19, I2 = 97%), atrial fibrillation (OR = 1.02, 95% CI = 1.01-1.04, I2 = 94%), heart failure (OR = 1.04, 95% CI = 1.03-1.06, I2 =97%), hypertension (OR = 1.16, 95% CI = 1.13-1.18, I2 = 28%), large artery stroke (OR = 1.14, 95% CI = 1.05-1.24, I2 = 0%), any ischemic stroke (OR = 1.09, 95% CI = 1.03-1.14, I2 = 60%), and primary intracranial hemorrhage (OR = 1.16, 95% CI = 1.05-1.27, I2 = 0%). No evidence suggested that insomnia is causally associated with cardioembolic or small vessel stroke.

CONCLUSIONS

Our results provide strong evidence supporting a possible causal association between insomnia and CVD risk. Strategies to treat insomnia may be promising targets for preventing CVDs.

CITATION

Zhang X, Sun Y, Ye S, et al. Associations between insomnia and cardiovascular diseases: a meta-review and meta-analysis of observational and Mendelian randomization studies. J Clin Sleep Med. 2024;20(12):1975-1984.

Association between self-reported napping and risk of cardiovascular disease and all-cause mortality: A meta-analysis of cohort studies

OBJECTIVES

This meta-analysis aims to assess the association between adult nap duration and risk of all-cause mortality and cardiovascular diseases (CVD).

METHODS

PubMed, Cochrane Library, Embase and Web of Science databases were searched to identify eligible studies. The quality of observational studies was assessed using the Newcastle-Ottawa Scale. We performed all statistical analyses using Stata software version 14.0. For the meta-analysis, we calculated hazard ratio (HR) and their corresponding 95% confidence intervals (CIs). To assess publication bias, we used a funnel plot and Egger's test.

RESULTS

A total of 21 studies involving 371,306 participants revealed varying methodological quality, from moderate to high. Those who indulged in daytime naps faced a significantly higher mortality risk than non-nappers (HR: 1.28; 95% CI: 1.18-1.38; I2 = 38.8%; P<0.001). Napping for less than 1 hour showed no significant association with mortality (HR: 1.00; 95% CI: 0.90-1.11; I2 = 62.6%; P = 0.971). However, napping for 1 hour or more correlated with a 1.22-fold increased risk of mortality (HR: 1.22; 95% CI: 1.12-1.33; I2 = 40.0%; P<0.001). The risk of CVD associated with napping was 1.18 times higher than that of non-nappers (HR: 1.18; 95% CI: 1.02-1.38; I2 = 87.9%; P = 0.031). Napping for less than 1 hour did not significantly impact CVD risk (HR: 1.03; 95% CI: 0.87-1.12; I2 = 86.4%; P = 0.721). However, napping for 1 hour or more was linked to a 1.37-fold increased risk of CVD (HR: 1.37; 95% CI: 1.09-1.71; I2 = 68.3%; P = 0.007).

CONCLUSIONS

Our meta-analysis indicates that taking a nap increases the risk of overall mortality and CVD mortality. It highlights that the long duration time of the nap can serve as a risk factor for evaluating both overall mortality and cardiovascular mortality.

Associations of sleep with cardiometabolic risk factors and cardiovascular diseases: An umbrella review of observational and mendelian randomization studies

Two researchers independently assessed studies published up to February 5, 2023, across PubMed, Web of Science, Embase, and Cochrane Library, to investigate the associations of sleep traits with cardiometabolic risk factors, as well as with cardiovascular diseases. Fourteen systematic reviews consisting of 23 meta-analyses, and 11 Mendelian randomization (MR) studies were included in this study. Short sleep duration was associated with a higher risk of obesity, type 2 diabetes (T2D), hypertension, stroke, and coronary heart disease (CHD) in observational studies, while a causal role was only demonstrated in obesity, hypertension, and CHD by MR. Similarly, long sleep duration showed connections with a higher risk of obesity, T2D, hypertension, stroke, and CHD in observational studies, none was supported by MR analysis. Both observational and MR studies indicated heightened risks of hypertension, stroke, and CHD in relation to insomnia. Napping was linked to elevated risks of T2D and CHD in observational studies, with MR analysis confirming a causal role in T2D. Additionally, snoring was correlated with increased risks of stroke and CHD in both observational and MR studies. This work consolidates existing evidence on a causal relationship between sleep characteristics and cardiometabolic risk factors, as well as cardiovascular diseases.

Causal relationship between chronic obstructive pulmonary disease and heart failure: A Mendelian randomization study

BACKGROUND

Causal association between chronic obstructive pulmonary disease (COPD) and heart failure (HF) has been controversial. This study used Mendelian Randomization (MR) analysis to clarify the potential causal connection between these two conditions.

OBJECTIVES

The purpose of the study was to investigate the causal relationship between COPD and HF based on the hypothesis that the genetic predisposition to COPD could lead to an increased risk of developing HF METHODS: A two-sample MR analysis of genetic data was performed for COPD and HF. This study was based on genome-wide association study (GWAS) data, including 6,915 patients with confirmed COPD and 186,723 controls. The odds ratios (ORs) and their 95 % confidence intervals (95 %CIs) were estimated using a fixed effects inverse variance weighting (IVW) method. Several supplementary statistical methods, including MR-Egger, weighted median, maximum likelihood, penalized weighted median, and random effects IVW, were applied to enhance the robustness of findings. Moreover, MR-PRESSO was employed as an alternative method for statistical detection.

RESULTS

Pooled data for HF were obtained from different GWASs, including 4,7309 confirmed HF patients and 930,014 controls. The MR analysis, based on the IVW model, revealed that COPD was significantly associated with an increased risk of HF. Specifically, the obtained findings showed that COPD patients had a higher risk of developing HF (Model 1: OR = 1.068, 95 %CI: 1.006-1.134, p = 0.031; Model 2: OR = 1.038, 95 %CI: 1.006-1.071, p = 0.020), indicating a causal relationship between COPD and HF. No evidence was found to suggest a reverse causal effect of HF on COPD incidence.

CONCLUSION

The MR analysis substantiates a causal link between COPD and HF, with no evidence supporting a reverse causation from HF to COPD. These findings underscore the importance of proactive COPD management as a potential strategy to prevent the development of HF, highlighting the need for targeted interventions in patients with COPD to mitigate their risk of HF.

Pioneering new frontiers in circadian medicine chronotherapies for cardiovascular health

Cardiovascular disease (CVD) is a global health concern. Circadian medicine improves cardiovascular care by aligning treatments with our body's daily rhythms and their underlying cellular circadian mechanisms. Time-based therapies, or chronotherapies, show special promise in clinical cardiology. They optimize treatment schedules for better outcomes with fewer side effects by recognizing the profound influence of rhythmic body cycles. In this review, we focus on three chronotherapy areas (medication, light, and meal timing) with potential to enhance cardiovascular care. We also highlight pioneering research in the new field of rest, the gut microbiome, novel chronotherapies for hypertension, pain management, and small molecules that targeting the circadian mechanism.

Causal effects of sleep traits on metabolic syndrome and its components: a Mendelian randomization study

PURPOSE

Previous observational studies have suggested an association between sleep disturbance and metabolic syndrome (MetS). However, it remains unclear whether this association is causal. This study aims to investigate the causal effects of sleep-related traits on MetS using Mendelian randomization (MR).

METHODS

Single-nucleotide polymorphisms strongly associated with daytime napping, insomnia, chronotype, short sleep, and long sleep were selected as genetic instruments from the corresponding genome-wide association studies (GWAS). Summary-level data for MetS were obtained from two independent GWAS datasets. Univariable and multivariable MR analyses were conducted to investigate and verify the causal effects of sleep traits on MetS.

RESULTS

The univariable MR analysis demonstrated that genetically predicted daytime napping and insomnia were associated with increased risk of MetS in both discovery dataset (OR daytime napping = 1.630, 95% CI 1.273, 2.086; OR insomnia = 1.155, 95% CI 1.108, 1.204) and replication dataset (OR daytime napping = 1.325, 95% CI 1.131, 1.551; OR insomnia = 1.072, 95% CI 1.046, 1.099). For components, daytime napping was positively associated with triglycerides (beta = 0.383, 95% CI 0.160, 0.607) and waist circumference (beta = 0.383, 95% CI 0.184, 0.583). Insomnia was positively associated with hypertension (OR = 1.101, 95% CI 1.042, 1.162) and waist circumference (beta = 0.067, 95% CI 0.031, 0.104). The multivariable MR analysis indicated that the adverse effect of daytime napping and insomnia on MetS persisted after adjusting for BMI, smoking, drinking, and another sleep trait.

CONCLUSION

Our study supported daytime napping and insomnia were potential causal factors for MetS characterized by central obesity, hypertension, or elevated triglycerides.

Association of Sleep Pattern and Genetic Susceptibility with Obstructive Sleep Apnea: A Prospective Analysis of the UK Biobank

Purpose

The prevalence of obstructive sleep apnea (OSA) is high worldwide. This study aimed to quantify the relationship between the incidence of OSA and sleep patterns and genetic susceptibility.

Methods

A total of 355,133 white British participants enrolled in the UK Biobank between 2006 and 2010 with follow-up data until September 2021 were recruited. We evaluated sleep patterns using a customized sleep scoring method based on the low-risk sleep phenotype, defined as follows: morning chronotype, 7-8 hours of sleep per day, never/rarely experience insomnia, no snoring, no frequent daytime sleepiness, never/rarely nap, and easily getting up early. The polygenic risk score was calculated to assess genetic susceptibility to OSA. Cox proportional hazard models were used to evaluate the associations between OSA and sleep patterns and genetic susceptibility.

Results

During a mean follow-up of 12.57 years, 4618 participants were diagnosed with OSA (age: 56.83 ± 7.69 years, women: 31.3%). Compared with those with a poor sleep pattern, participants with a normal (HR: 0.42, 95% CI: 0.38-0.46), ideal (HR: 0.21, 95% CI: 0.19-0.24), or optimal (HR: 0.15, 95% CI: 0.12-0.18) sleep pattern were significantly more likely to have OSA. The genetic susceptibility of 173,239 participants was calculated, and the results showed that poor (HR: 3.67, 95% CI: 2.95-4.57) and normal (HR: 1.89, 95% CI: 1.66-2.16) sleep patterns with high genetic susceptibility can increase the risk for OSA.

Conclusion

This large-scale prospective study provides evidence suggesting that sleep patterns across seven low-risk sleep phenotypes may protect against OSA in individuals with varying degrees of genetic susceptibility.

Causal relationship between nutritional assessment phenotypes and heart failure: A Mendelian randomization study

Introduction

Malnutrition is strongly associated with heart failure (HF); however, the causal link remains unclear. We used Mendelian randomization (MR) to infer causal associations between different nutritional assessment phenotypes and HF and to analyze whether these associations were mediated by common HF risk factors.

Methods

Two-sample bidirectional MR was used to infer causal associations between nutritional assessment phenotypes and HF. Mutual influences between different nutritional assessment phenotypes and potential correlations were estimated using multivariate MR methods. Two-step MR was used to quantify the mediating effects of common HF risk factors on the causal associations.

Results

Three phenotypes were positively associated with the development of HF: waist circumference (WC) (odds ratio [OR] = 1.74; 95% confidence interval [CI], 1.60-1.90; P = 3.95 × 10-39), body mass index (BMI) (OR = 1.70; 95%CI, 1.60-1.80; P = 1.35 × 10-73), and whole body fat mass (WBFM) (OR = 1.54; 95%CI, 1.44-1.65; P = 4.82 × 10-37). Multivariate MR indicated that WBFM remained positively associated with HF after conditioning on BMI and WC (OR = 2.05; 95%CI, 1.27-3.31; P = 0.003). Three phenotypes were negatively correlated with the development of HF: usual walking pace (UWP) (OR = 0.40; 95%CI, 0.27-0.60; P = 8.41 × 10-6), educational attainment (EA) (OR = 0.73; 95%CI, 0.67-0.79; P = 2.27 × 10-13), and total cholesterol (TC) (OR = 0.90; 95%CI, 0.84-0.96; P = 4.22 × 10-3). There was a bidirectional causality between HF and UWP (Effect estimate = -0.03; 95%CI, -0.05 to -0.01; P = 1.95 × 10-3). Mediation analysis showed that common risk factors for HF (hypertension, coronary artery disease, cardiomyopathy, and valvular heart disease) mediated these causal associations (all P < 0.05).

Conclusions

BMI, WC, and WBFM are potential risk factors for HF, and the correlation between WBFM and HF was significantly stronger than that between BMI and WC, and HF. EA, UWP, and TC are potential protective factors against HF. Common risk factors for HF mediate these causal pathways. Early identification of potential risk or protective factors for HF patients from the dimension of nutritional status is expected to further improve patient outcomes.

Screen time in the development of cardiovascular diseases: A two-sample Mendelian randomization study

BACKGROUND AND AIMS

Coronary artery disease (CAD), heart failure (HF), and ischemic heart disease (IHD) are three common cardiovascular diseases that are closely associated with metabolic activity. The global incidence and prevalence of these conditions are on the rise, primarily due to unhealthy lifestyles, aging populations, and the increasing prevalence of obesity and diabetes. Excessive screen time has emerged as a potential risk factor for various adverse health outcomes, although limited research has explored its relationship with cardiovascular disease outcomes.

METHODS AND RESULTS

A Mendelian randomization (MR) study was conducted, employing exposure-associated genetic variants as instrumental variables to explore the causal relationship between screen time use and cardiovascular disease outcomes. Single nucleotide polymorphisms (SNPs) were utilized as pooled data for the genetic variable instrument, investigating the association between screen use duration and three types of cardiovascular diseases: coronary artery disease (CAD), heart failure (HF), and ischemic heart disease (IHD). Through the MR analysis, it was revealed that the use of mobile phones and TV screens exhibited a significant causal association with the occurrence of CAD, heart failure, and IHD. However, no significant association was observed between the use of computers and these three types of cardiovascular diseases.

CONCLUSION

Our study suggests that excessive screen time use is associated with the development of cardiovascular disease. However, it should be noted that the consequences of screen time can vary depending on the reasons and purposes for its use. Implementing reasonable control over screen time, particularly for entertainment purposes, holds promise as a potential approach to mitigating cardiovascular disease.

Revisiting an old relationship: the causal associations of the ApoB/ApoA1 ratio with cardiometabolic diseases and relative risk factors-a mendelian randomization analysis

BACKGROUND

It has been confirmed that the ApoB/ApoA1 ratio is closely associated with the incidence of cardiometabolic diseases (CMD). However, due to uncontrolled confounding factors in observational studies, the causal relationship of this association remains unclear.

METHODS

In this study, we extracted the ApoB/ApoA1 ratio and data on CMD and its associated risk factors from the largest European Genome-Wide Association Study. The purpose was to conduct Mendelian Randomization (MR) analysis. The causal relationship between the ApoB/ApoA1 ratio and CMD was evaluated using both univariable and multivariable MR analyses. Furthermore, bidirectional MR analysis was performed to estimate the causal relationship between the ApoB/ApoA1 ratio and risk factors for CMD. The final verification confirmed whether the ApoB/ApoA1 ratio exhibits a mediating effect in CMD and related risk factors.

RESULTS

In terms of CMD, a noteworthy correlation was observed between the increase in the ApoB/ApoA1 ratio and various CMD, including ischemic heart disease, major adverse cardiovascular events, aortic aneurysm, cerebral ischemic disease and so on (all PFDR<0.05). Meanwhile, the ApoB/ApoA1 ratio was significantly associated with CMD risk factors, such as hemoglobin A1c, fasting insulin levels, waist-to-hip ratio, sedentary behavior, and various others, demonstrating a notable causal relationship (all PFDR<0.05). Additionally, the ApoB/ApoA1 ratio played a mediating role in CMD and relative risk factors.

CONCLUSIONS

This MR study provides evidence supporting the significant causal relationship between the ApoB/ApoA1 ratio and CMD and its risk factors. Moreover, it demonstrates the mediating effect of the ApoB/ApoA1 ratio in CMD and its risk factors. These findings suggest that the ApoB/ApoA1 ratio may serve as a potential indicator for identifying the risk of developing CMD in participants.

Eveningness is associated with coronary artery calcification in a middle-aged Swedish population

Coronary artery calcification (CAC) is an established imaging biomarker of subclinical atherosclerosis, but its relationship to diurnal preference is not well studied. We investigated the association between chronotype and CAC in the Swedish CArdioPulmonary bioImage Study (SCAPIS) pilot cohort. Participants aged 50-64 years were randomly recruited and underwent extensive examination including imaging and accelerometry-assessed physical activity. 771 participants (47.3 % male, 57.6 ± 4.4 years) were included in this cross-sectional analysis. CAC was assessed by non-contrast computed tomography, and a CAC score > 10 was considered significant calcification. Self-assessed chronotype was classified as extreme morning, moderate morning, intermediate, moderate evening, or extreme evening. 10-year risk of first-onset cardiovascular disease was estimated by the Systemic Coronary Risk Evaluation 2 (SCORE2). Significant CAC was present in 29 % of the cohort. CAC prevalence increased from extreme morning to extreme evening type (22 %, 28 %, 29 %, 27 %, 41 % respectively, p = 0.018). In a multivariate logistic regression model controlling for confounders, extreme evening chronotype was independently associated with increased CAC prevalence compared to extreme morning type (OR 1.90, [95%CI 1.04-3.46], p = 0.037). When stratified by SCORE2 risk category (low: <5 %; moderate: 5 to <10 %; high: ≥10 %), significant CAC was most prevalent among extreme evening chronotypes in the low and moderate-risk groups, while chronotype seemed less important in the high-risk group (p = 0.011, p = 0.023, p = 0.86, respectively). Our findings suggest circadian factors may play an important role in atherosclerosis and should be considered in early cardiovascular prevention.

The predictive, preventive, and personalized medicine of insomnia: gut microbiota and inflammation

Background

The human gut microbiota (GM) has been recognized as a significant factor in the development of insomnia, primarily through inflammatory pathways, making it a promising target for therapeutic interventions. Considering the principles of primary prediction, targeted prevention, and personalized treatment medicine (PPPM), identifying specific gut microbiota associated with insomnia and exploring the underlying mechanisms comprehensively are crucial steps towards achieving primary prediction, targeted prevention, and personalized treatment of insomnia.

Working hypothesis and methodology

We hypothesized that alterations in the composition of specific GM could induce insomnia through an inflammatory response, which postulates the existence of a GM-inflammation-insomnia pathway. Mendelian randomization (MR) analyses were employed to examine this pathway and explore the mediative effects of inflammation. We utilized genetic proxies representing GM, insomnia, and inflammatory indicators (including 41 circulating cytokines and C-reactive protein (CRP)), specifically identified from European ancestry. The primary method used to identify insomnia-related GM and examine the medicative effect of inflammation was the inverse variance weighted method, supplemented by the MR-Egger and weighted median methods. Our findings have the potential to identify individuals at risk of insomnia through screening for GM imbalances, leading to the development of targeted prevention and personalized treatment strategies for the condition.

Results

Nine genera and three circulating cytokines were identified to be associated with insomnia; only the associations of Clostridium (innocuum group) and β-NGF on insomnia remained significant after the FDR test, OR = 1.08 (95% CI = 1.04-1.12, P = 1.45 × 10-4, q = 0.02) and OR = 1.06 (95% CI = 1.02-1.10, P = 1.06 × 10-3, q = 0.04), respectively. CRP was associated with an increased risk of insomnia, OR = 1.05 (95% CI = 1.01-1.10, P = 6.42 × 10-3). CRP mediated the association of Coprococcus 1, Holdemania, and Rikenellaceae (RC9gut group) with insomnia. No heterogeneity or pleiotropy were detected.

Conclusions

Our study highlights the role of specific GM alterations in the development of insomnia and provides insights into the mediating effects of inflammation. Targeting these specific GM alterations presents a promising avenue for advancing the transition from reactive medicine to PPPM in managing insomnia, potentially leading to significant clinical benefits.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-023-00345-1.

Potential genetic and epigenetic mechanisms in insomnia: A systematic review

Insomnia is a stress-related sleep disorder conceptualised within a diathesis-stress framework, which it is thought to result from predisposing factors interacting with precipitating stressful events that trigger the development of insomnia. Among predisposing factors genetics and epigenetics may play a role. A systematic review of the current evidence for the genetic and epigenetic basis of insomnia was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) system. A total of 24 studies were collected for twins and family heritability, 55 for genome-wide association studies, 26 about candidate genes for insomnia, and eight for epigenetics. Data showed that insomnia is a complex polygenic stress-related disorder, and it is likely to be caused by a synergy of genetic and environmental factors, with stress-related sleep reactivity being the important trait. Even if few studies have been conducted to date on insomnia, epigenetics may be the framework to understand long-lasting consequences of the interaction between genetic and environmental factors and effects of stress on the brain in insomnia. Interestingly, polygenic risk for insomnia has been causally linked to different mental and medical disorders. Probably, by treating insomnia it would be possible to intervene on the effect of stress on the brain and prevent some medical and mental conditions.

The relationship between gut microbiota and insomnia: a bi-directional two-sample Mendelian randomization research

Introduction

Insomnia is the second most common mental health issue, also is a social and financial burden. Insomnia affects the balance between sleep, the immune system, and the central nervous system, which may raise the risk of different systemic disorders. The gut microbiota, referred to as the "second genome," has the ability to control host homeostasis. It has been discovered that disruption of the gut-brain axis is linked to insomnia.

Methods

In this study, we conducted MR analysis between large-scale GWAS data of GMs and insomnia to uncover potential associations.

Results

Ten GM taxa were detected to have causal associations with insomnia. Among them, class Negativicutes, genus Clostridiuminnocuumgroup, genus Dorea, genus Lachnoclostridium, genus Prevotella7, and order Selenomonadalesare were linked to a higher risk of insomnia. In reverse MR analysis, we discovered a causal link between insomnia and six other GM taxa.

Conclusion

It suggested that the relationship between insomnia and intestinal flora was convoluted. Our findings may offer beneficial biomarkers for disease development and prospective candidate treatment targets for insomnia.

Relationship of triglyceride-glucose index with cardiometabolic multi-morbidity in China: evidence from a national survey

BACKGROUND

Cardiometabolic multi-morbidity (CMM) is emerging as a global healthcare challenge and a pressing public health concern worldwide. Previous studies have principally focused on identifying risk factors for individual cardiometabolic diseases, but reliable predictors of CMM have not been identified. In the present study, we aimed to characterize the relationship of triglyceride-glucose (TyG) index with the incidence of CMM.

METHODS

We enrolled 7,970 participants from the China Health and Retirement Longitudinal Study (CHARLS) and placed them into groups according to quartile of TyG index. The endpoint of interest was CMM, defined as the presence of at least two of the following: stroke, heart disease, and diabetes mellitus. Cox regression models and multivariable-adjusted restricted cubic spline (RCS) curves were used to evaluate the relationship between TyG index and CMM.

RESULTS

In total, 638 (8.01%) incident cases of CMM were recorded among the participants who did not have CMM at baseline (2011) during a median follow-up of 84 months (interquartile range, 20‒87 months). The incidences of CMM for the participants in quartiles (Q) 1-4 of TyG index were 4.22%, 6.12%, 8.78%, and 12.60%, respectively. A fully adjusted Cox model showed that TyG index was closely associated with the incidence of CMM: the hazard ratio (HR) [95% confidence interval (CI)] for each 1.0-unit increment in TyG index for CMM was 1.54 (1.29-1.84); and the HRs (95% CIs) for Q3 and Q4 (Q1 as reference) of the TyG index for CMM were 1.41 (1.05-1.90) and 1.61 (1.18-2.20), respectively. The association of TyG index with the incidence of CMM was present in almost all the subgroups, and persisted in the sensitivity analyses and additional analyses. Multivariable-adjusted RCS analysis revealed a significant dose-response relationship of TyG index with the risk of CMM (overall P < 0.001; non-linear P = 0.129).

CONCLUSIONS

We found that a high TyG index is associated with a higher risk of incident CMM. This finding may have significance for clinical practice and facilitate the creation of a personalized prevention strategy that involves monitoring the TyG index.

Poor sleep and shift work associate with increased blood pressure and inflammation in UK Biobank participants

Disrupted circadian rhythms have been linked to an increased risk of hypertension and cardiovascular disease. However, many studies show inconsistent findings and are not sufficiently powered for targeted subgroup analyses. Using the UK Biobank cohort, we evaluate the association between circadian rhythm-disrupting behaviours, blood pressure (SBP, DBP) and inflammatory markers in >350,000 adults with European white British ancestry. The independent U-shaped relationship between sleep length and SBP/DBP is most prominent with a low inflammatory status. Poor sleep quality and permanent night shift work are also positively associated with SBP/DBP. Although fully adjusting for BMI in the linear regression model attenuated effect sizes, these associations remain significant. Two-sample Mendelian Randomisation (MR) analyses support a potential causal effect of long sleep, short sleep, chronotype, daytime napping and sleep duration on SBP/DBP. Thus, in the current study, we present a positive association between circadian rhythm-disrupting behaviours and SBP/DBP regulation in males and females that is largely independent of age.

Sleep duration and its association with adiposity markers in adolescence: a cross-sectional and longitudinal study

AIMS

Large studies linking adolescents' objectively measured sleep duration and adiposity markers are lacking. We characterized sleep duration and its cross-sectional and longitudinal associations with adiposity markers in adolescence.

METHODS AND RESULTS

Seven-day accelerometry was performed in a cohort of adolescents enrolled in the SI! Program for Secondary Schools trial in Spain at approximately ages 12 (1216 adolescents, 49.6% girls), 14 (1026 adolescents, 51.3% girls), and 16 (872 adolescents, 51.7% girls) years. Participants were classified as very short sleepers (VSS; <7 h), short sleepers (SS; 7-<8 h), or recommended-time sleepers (RTS; 8-10 h). Adjusted associations between sleep duration and adiposity markers were analysed using generalized linear and Poisson models. At ∼12 years, 33.7% of adolescents met sleep recommendations, and this percentage decreased with advancing age (22.6% at ∼14 and 18.7% at ∼16 years). Compared with RTS, overweight/obesity prevalence ratios at ∼12, 14, and 16 years among SS were 1.19 [95% confidence interval (CI): 1.09-1.30], 1.41 (95% CI: 1.34-1.48), and 0.99 (95% CI: 0.77-1.26) and among VSS were 1.30 (95% CI: 1.28-1.32), 1.93 (95% CI: 1.41-2.64), and 1.32 (95% CI: 1.26-1.37). Compared with adolescents who always met sleep recommendations, the prevalence of overweight/obesity was ∼5 times higher in those never meeting recommendations or meeting them only once. Similar trends were observed for the waist-to-height ratio (P = 0.010) and fat mass index (P = 0.024).

CONCLUSION

Most adolescents did not meet sleep recommendations. Shorter sleep duration was independently associated with unfavourable adiposity markers, and such adverse impact was cumulative. Health promotion programmes should emphasize the importance of good sleep habits.

Association Between Sleep Duration and Stroke in Different Status of Metabolic Syndrome: A Cross-Sectional Study in Shanghai Adult Residents

Purpose

This study aimed to investigate the relationship between sleep duration (SD) and stroke, and examine the effects of SD on stroke with or without metabolic syndrome (Mets) and its components among the adult residents in Shanghai, China.

Participants and Methods

A total of 20,245 participants (51.72% male, mean age 44.66 years) were included from Shanghai Chronic Disease and Risk Factors Surveillance (SCDRFS) in 2017. The weighted logistic regressions were performed to examine the associations between SD and stroke in different status of Mets and its components.

Results

The mean SD was 7.51±0.03 h/d. After adjusting for all the potential factors, SD<6 h/d (OR=1.73, 95% CI: 1.35-2.20) or ≥10 h/d (OR=1.66, 95% CI: 1.08-2.57) was significantly positively associated with stoke in the total participants; moreover, in the non-Mets group, only SD<6 h/d (OR=1.77, 95% CI: 1.19, 2.64) significantly increased the risk of stroke; while, in the Mets group, SD<6 h/d (OR=1.80, 95% CI:1.17-2.76) and ≥10 h/d (OR=1.97, 95% CI: 1.00-3.88) both had a positive significantly association with stoke. In addition, the effects of SD<6 h/d on stroke were more pronounced among those with high WC (OR=2.24, 95% CI: 1.40-3.58) and high TG (OR=2.60, 95% CI: 1.86-3.62), and the effects of SD≥10 h/d on stroke were more evident among those with high TG (OR=2.28, 95% CI: 1.02-5.08) and high FBG (OR=2.58, 95% CI: 1.30-5.10).

Conclusion

Both short and long SD were significantly positively associated with stroke in the total participants, and the associations were stronger in the Mets group; conversely, in the non-Mets group, only short SD was significantly positively associated with stroke, and no significant association was observed between long SD and stroke. Therefore, more precise sleep measures may be needed to prevent stroke according to the different status of Mets.

Association of sleep behaviors, insulin resistance surrogates, and the risk of hypertension in Chinese adults with type 2 diabetes mellitus

Objective

Our aim was to evaluate the association between midday napping, combined sleep quality, and insulin resistance surrogates and the risk of hypertension in patients with type 2 diabetes mellitus (T2DM).

Methods

Data were collected using a standardized questionnaire. Binary logistic regression was performed to estimate the odds ratio (OR) and 95% confidence interval (CI) for the risk of hypertension. Systolic and diastolic blood pressure were grouped as categorical variables and unpaired two-sided Student's t-test and Spearman correlation analysis were performed to estimate the association between different blood pressure levels and insulin resistance surrogates.

Results

The overall prevalence rate of hypertension was 50%. Age (OR = 1.056, 95% CI:1.044-1.068), poor sleep quality (OR = 1.959, 95% CI:1.393-2.755), hyperlipidemia (OR = 1.821, 95% CI:1.462-2.369), family history of hypertension (OR = 2.811, 95% CI:2.261-3.495), and obesity (OR = 5.515, 95% CI:1.384-21.971) were significantly associated with an increased risk of hypertension. Midday napping for 1-30 min was negatively correlated with the risk of hypertension (OR = 0.534, 95% CI:0.305-0.936, P <0.05).

Conclusion

Poor sleep quality and obesity are independent risk factors for hypertension. Midday napping (1-30 min) is associated with a decreased risk of hypertension in patients with T2DM.

Long Sleep Duration and Stroke-Highly Linked, Poorly Understood

Stroke is one of the leading causes of disability and mortality. Both short and long sleep durations are associated with adverse health outcomes. Cross-sectional studies have shown an increased prevalence of stroke in long sleepers. Long sleep duration increases stroke incidence and mortality in prospective epidemiological studies. Accumulating evidence suggests that the magnitude of the association between sleep and stroke appears to be stronger for longer sleep than shorter sleep, yielding a J-shaped curve. Potential links between long sleep duration and stroke include increased incidence of diabetes and atrial fibrillation, elevated levels of inflammation, arterial stiffness, and blood pressure variability. Long sleep duration is a strong marker and a plausible risk factor for stroke and should be considered in future scoring for risk stratification and stroke prevention.

The association between daytime napping and risk of type 2 diabetes is modulated by inflammation and adiposity: Evidence from 435 342 UK-Biobank participants

BACKGROUND

Existing evidence concerning the relationship between daytime napping and type 2 diabetes (T2D) is inconsistent, and whether the effects of napping differ by body fat percentage (BFP) and C-reactive protein (CRP) is unclear. We aimed to investigate the association between daytime napping frequency and T2D risk and whether such an association was modified by BFP and CRP.

METHODS

We included 435 342 participants free of diabetes from the UK Biobank. Participants were categorized as nonnappers, occasional nappers, and frequent nappers based on napping frequency, and BFP/CRP was divided into quartiles. Cox proportional hazards models were used.

RESULTS

During a median follow-up of 9.2 years, 17 592 T2D cases occurred. Higher frequency of daytime napping was significantly associated with an increased risk of T2D. Compared with nonnappers, the adjusted hazard ratios (HRs) for occasional nappers and habitual nappers were 1.28 (95% confidence interval [CI]: 1.24-1.32) and 1.49 (95% CI: 1.41-1.57), respectively. There was a significant additive and multiplicative interaction (relative excess risk due to interaction [RERI] = 0.490, 95% CI 0.307-0.673; p for multiplicative interaction <.001) between napping and BFP, whereby a higher hazard of T2D associated with more frequent napping was greatest among participants in the highest BFP quartile (HR = 4.45, 95% CI: 3.92-5.06). The results for CRP were similar (RERI = 0.266, 95% CI: 0.094-0.439; p for multiplicative interaction <.001).

CONCLUSIONS

Higher daytime napping frequency is associated with an increased T2D risk, and such relationships are modified by BFP and CRP. These findings underscore the importance of adiposity and inflammation control to mitigate diabetes risk.

Causal association of sleep disturbances and low back pain: A bidirectional two-sample Mendelian randomization study

BACKGROUND

Previous observational studies have shown that low back pain (LBP) often coexists with sleep disturbances, however, the causal relationship remains unclear. In the present study, the causal relationship between sleep disturbances and LBP was investigated and the importance of sleep improvement in the comprehensive management of LBP was emphasized.

METHODS

Genetic variants were extracted as instrumental variables (IVs) from the genome-wide association study (GWAS) of insomnia, sleep duration, short sleep duration, long sleep duration, and daytime sleepiness. Information regarding genetic variants in LBP was selected from a GWAS dataset and included 13,178 cases and 164,682 controls. MR-Egger, weighted median, inverse-variance weighted (IVW), penalized weighted median, and maximum likelihood (ML) were applied to assess the causal effects. Cochran's Q test and MR-Egger intercept were performed to estimate the heterogeneity and horizontal pleiotropy, respectively. Outliers were identified and eliminated based on MR-PRESSO analysis to reduce the effect of horizontal pleiotropy on the results. Removing each genetic variant using the leave-one-out analysis can help evaluate the stability of results. Finally, the reverse causal inference involving five sleep traits was implemented.

RESULTS

A causal relationship was observed between insomnia-LBP (OR = 1.954, 95% CI: 1.119-3.411), LBP-daytime sleepiness (OR = 1.011, 95% CI: 1.004-1.017), and LBP-insomnia (OR = 1.015, 95% CI: 1.004-1.026), however, the results of bidirectional MR analysis between other sleep traits and LBP were negative. The results of most heterogeneity tests were stable and specific evidence was not found to support the disturbance of horizontal multiplicity. Only one outlier was identified based on MR-PRESSO analysis.

CONCLUSION

The main results of our research showed a potential bidirectional causal association of genetically predicted insomnia with LBP. Sleep improvement may be important in comprehensive management of LBP.

Relations among perceived stress, fatigue, and sleepiness, and their effects on the ambulatory arterial stiffness index in medical staff: A cross-sectional study

Objective

To explore the relations among perceived stress, fatigue, sleepiness, and the pathway of their effects on the ambulatory arterial stiffness index (AASI) among medical staff.

Methods

This cross-sectional study was conducted at a tertiary hospital in Wuhan, China. Perceived stress, fatigue, and sleepiness were measured using the perceived stress scale (PSS), Fatigue assessment scale (FAS), and Epworth Sleepiness Scale (ESS), respectively. AASI was obtained from 24-h ambulatory blood pressure monitoring. Path analysis was used to clarify the relations among the PSS, FAS, and ESS scores, and their relations to AASI values.

Results

A total of 153 participants were included herein. The PSS and FAS correlated with the ESS (r = 0.424, p < 0.001), and the PSS correlated with the FAS (r = 0.614, p < 0.001). In addition, the ESS correlated with the AASI (r = 0.225, p = 0.005). According to the path analysis results, the PSS and FAS had no direct effect on the AASI, but did have an indirect effect on this index (β = 0.059, 95% confidence interval [CI] = 0.017-0.128, p = 0.005; β = 0.059, 95%CI = 0.016-0.135, p = 0.006, respectively) by influencing the ESS (β = 0.263, β = 0.262, p = 0.004).

Conclusion

Sleepiness was a mediator of the effects of perceived stress and fatigue on AASI.