Long Sleep Duration Is an Independent Risk Factor for Incident Atrial Fibrillation in a Chinese Population: A Prospective Cohort Study

Insomnia is related to long-term atrial fibrillation recurrence following radiofrequency ablation

OBJECTIVE

Atrial fibrillation (AF), the most common cardiac arrhythmia, presents significant health challenges, and the intricate connection between insomnia and AF has garnered substantial attention. This cohort study aims to investigate the relationship between insomnia and AF recurrences following radiofrequency ablation.

MATERIALS AND METHODS

Data were retrieved from an electronic database of patients who underwent radiofrequency ablation for AF. The primary endpoint was AF recurrence. We utilized a multivariable Cox model, coupled with three propensity score methods, for analysis.

RESULTS

Between January 1, 2017, and June 1, 2022, 541 patients who underwent radiofrequency ablation for AF were recorded in the database. After excluding 185 patients, the final cohort comprised 356 patients. Among them, 68 were afflicted by insomnia, while 288 were not. Over a median follow-up of 755 days, one patient died, and 130 (36.5%) experienced AF recurrence. Multivariate Cox regression analysis revealed that the insomnia group had a higher risk of AF recurrence compared to the non-insomnia group (HR: 1.83, 95% CI: 1.16-2.89). Further landmark analysis showed no significant difference in AF recurrence rates during the initial 1-year follow-up. However, beyond 1 year, the insomnia group demonstrated a significantly higher AF recurrence rate. As the number of insomnia symptoms increased, the risk of AF recurrence also rose significantly, indicating a dose-response relationship.

CONCLUSION

This study establishes a significant link between insomnia and long-term AF recurrence following radiofrequency ablation. It underscores the importance of identifying and addressing insomnia in patients with AF undergoing radiofrequency ablation.

Analyzing the impact of sleep duration on atrial fibrillation risk: a comprehensive systematic review and meta-analysis

BACKGROUND

Recent studies have suggested an association between sleep duration and cardiovascular diseases; however, the link to AF is inconclusive. This study aimed to explore the relationship between sleep duration and AF by conducting a systematic review and meta-analysis of primary studies to provide evidence of the link between insufficient sleep and AF.

METHODS

A review of the existing literature was conducted to identify the primary studies that examined the association between AF and sleep duration. The inquiry spanned databases, including PubMed, Embase, MEDLINE, and Google Scholar, from their inception through October 2023.

RESULTS

Meta-analysis revealed a statistically significant association (p < 0.01) between shorter sleep duration and the incidence of AF (hazard ratio (HR), 1.18; 95% CI, 1.03-1.34; I2 = 89%). Conversely, longer sleep duration did not exhibit a statistically significant association with the incidence of AF (HR, 1.03; 95% CI, 0.92-1.14; I2 = 66%, p = 0.02). The sensitivity analysis demonstrated reduced heterogeneity after excluding specific studies.

CONCLUSION

Insufficient sleep duration was associated with an increased risk of AF, whereas a longer sleep duration did not show a significant correlation. Standardized methods for sleep assessment and AF diagnosis as well as adjustments for confounding factors are suggested for future studies to improve the clarity and understanding of these associations.

Association Between Sleep Duration and Atrial Fibrillation: A Narrative Review

Sleep duration is a substantial risk factor for several cardiovascular diseases, including atrial fibrillation (AF). Despite much research, the precise nature of the relationship between the amount of sleep and AF remains unclear. This narrative review explores the relationship between AF and sleep duration, looking at genetic, mechanistic, and epidemiological data to explain this association. A U-shaped association (nonlinear relationship or curvilinear association) between sleep duration and AF has been seen, where longer and shorter sleep duration, more or less than seven to eight hours, have been associated with increased AF risk. Multiple mechanisms such as autonomic dysfunction, inflammation, and structural atrial remodeling have been proposed linking sleep disturbances to AF. Moreover, confounding factors such as individual lifestyle, comorbidities, and sleep quality could affect this association. Additionally, the interpretation of study results is further impacted by methodological limitations, including self-reported sleep duration and observational study designs. It is imperative to comprehend the complex relationship between sleep duration and AF to develop effective preventive and therapeutic methods. The main goals of future research should focus on prospective cohort studies with objective sleep metrics, exploring the mechanistic pathways, and comprehensive confounder adjustments that link sleep disturbances to AF. In summary, addressing sleep disturbances may represent one of the novel approaches to AF prevention and management, with potential implications for improving cardiovascular health and reducing AF-related morbidity and mortality.

Relationship between daytime napping and cardiovascular disease: A two-sample mendelian randomization study

OBJECTIVE

Daytime napping has been reported to have a potential association with an increased risk of cardiovascular diseases (CVDs) in several cohort studies, but the causal effects are unclear. In this study, we aimed to investigate the relationship between daytime napping and CVDs, as well as to validate causality in this relationship by Mendelian randomization (MR).

METHODS

A two-sample MR method was used to evaluate the causal effect of daytime napping on CVDs. The exposure of daytime napping was extracted from publicly available genome-wide association studies (GWASs) in the UK Biobank, and the outcomes of 14 CVDs were obtained from the FinnGen consortium. A total of 49 single-nucleotide polymorphisms (SNPs) were used as the instrumental variables. The effect estimates were calculated by using the inverse-variance weighted method.

RESULTS

The MR analyses showed that genetically predicted daytime napping was associated with an increased risk of five CVDs, including heart failure (odds ratio (OR): 1.71, 95% CI: 1.19-2.44, p = 0.003), hypertension (OR: 1.51, 95% CI: 1.05-2.16, p = 0.026), atrial fibrillation (OR: 1.71, 95% CI: 1.02-2.88, p = 0.042), cardiac arrythmias (OR: 1.47, 95% CI: 1.47, 95% CI: 1.01-2.13, p = 0.042) and coronary atherosclerosis (OR: 1.77, 95% CI: 1.17-2.68, p = 0.006). No significant influence was observed for other CVDs.

CONCLUSION

This two-sample MR analysis suggested that daytime napping was causally associated with an increased risk of heart failure, hypertension, atrial fibrillation, cardiac arrythmias and coronary atherosclerosis.

Association of sleep duration with atrial fibrillation/flutter mortality in the United States: a cross-sectional analysis

BACKGROUND

The association between sleep duration and atrial fibrillation risk is poorly understood, with inconsistent findings reported by several studies. We sought to assess the association between long sleep duration and mortality due to atrial fibrillation/atrial flutter (AF/AFL).

METHODS

The 2016-2020 Centers for Disease Control and Prevention (CDC) Wide-Ranging Online Data for Epidemiologic Research dataset was used to identify death records secondary to AF/AFL in the United States population. We used the 2018 Behavioral Risk Factor Surveillance System (BRFSS) dataset of sleep duration at the county level. All counties were grouped into quartiles based on the percentage of their population with long sleep duration (i.e., ≥ 7 h), Q1 being the lowest and Q4 the highest quartile. Age-adjusted mortality rates (AAMR) were calculated for each quartile. County Health Rankings for Texas were used to adjust the AAMR for comorbidities using linear regression.

RESULTS

Overall, the AAMR for AF/AFL were highest in Q4 (65.9 [95% CI, 65.5-66.2] per 100,000 person-years) and lowest in Q1 (52.3 [95% CI, 52.1-52.5] per 100,000 person-years). The AAMR for AF/AFL increased stepwise from the lowest to highest quartiles of the percentage population with long sleep duration. After adjustment for the county health ranks of Texas, long sleep duration remained associated with a significantly higher AAMR (coefficient 220.6 (95% CI, 21.53-419.72, p-value = 0.03).

CONCLUSIONS

Long sleep duration was associated with higher AF/AFL mortality. Increased focus on risk reduction for AF, public awareness about the importance of optimal sleep duration, and further research to elucidate a potential causal relationship between sleep duration and AF are warranted.

Short sleep duration and atrial fibrillation risk: A comprehensive analysis of observational cohort studies and genetic study

BACKGROUND

Previous observational studies are inconclusive on whether an association exists between short sleep duration and the high risk of developing atrial fibrillation (AF). Understanding their potential association would be of great clinical significance. Thus, in this study, we aimed to explore their causal relationship.

METHODS AND RESULTS

We meta-analyzed the association between short sleep duration and the risk of developing AF by including six observational studies. Based on genetic susceptibility analysis using the mendelian randomization (MR) method, we identified 16 genetic loci that might link short sleep duration and the high risk of developing AF. Meta-analysis showed a significant association between short sleep duration and a higher risk of developing AF (RR = 1.06, 95% CI 1.02-1.11, P = 0.005). However, the fixed-effect and random-effect inverse variance weighted (IVW) models using the MR method showed a non-obvious effect of short sleep duration on the risk of developing AF (OR, 0.979; 95% CI, 0.880-1.089, P = 0.693; OR, 0.979; 95% CI, 0.857-1.117, P = 0.750, respectively). Other models, also showed no statistical difference. No heterogeneity or asymmetry was observed, as Cochran's Q test showed. The leave-one-out sensitivity analysis demonstrated good robust results, which were not subject to directional pleiotropy.

CONCLUSION

Meta-analysis and MR analysis demonstrated inconsistent results on the relationship between short sleep duration and a high risk of developing AF. Specifically, while meta-analysis confirmed that short sleep duration increases the risk of developing AF, MR analysis did not support a causal association between genetically determined short sleep and risk of AF.

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.

Association of Sleep Duration, Midday Napping with Atrial Fibrillation in Patients with Hypertension

Objective

This study aimed to assess the associations of sleep duration, midday napping and the risk of atrial fibrillation (AF) in patients with hypertension.

Methods

We conducted a cross-sectional study enrolling 11,524 hypertensive participates from the Chinese Hypertension Registry Study. Information on sleep duration and midday napping were obtained by a self-administered questionnaire. Multivariate logistic regression analyses were performed to estimate odds ratio (OR) and 95% confidence intervals (CIs) for the risk of AF.

Results

Compared with sleeping 6 to ≤8 hours/night, those reporting shorter sleep duration (≤5 hours/night) had a greater risk of AF (OR 1.95; 95% CI 1.28–2.95) in the fully adjusted model, while longer sleep (≥9 hours/night) was not significantly associated with the risk of AF. Compared with nonhabitual nappers, nappers had a higher risk of AF (OR 1.28; 95% CI 1.03–1.60) in the fully adjusted model. Moreover, we observed significant joint effects of sleeping ≤5 hours/night and nap (OR 2.13; 95% CI 1.09–4.14) on the risk of AF after adjusting for confounding factors.

Conclusion

Short sleep duration and midday napping were independently and jointly associated with higher risks of AF in patients with hypertension.

Sleep duration and atrial fibrillation risk in the context of predictive, preventive, and personalized medicine: the Suita Study and meta-analysis of prospective cohort studies

Background

Short and long sleep durations are common behaviors that could predict several cardiovascular diseases. However, the association between sleep duration and atrial fibrillation (AF) risk is not well-established. AF is preventable, and risk prevention approaches could reduce its occurrence. Investigating whether sleep duration could predict AF incidence for possible preventive interventions and determining the impact of various lifestyle and clinical characteristics on this association to personalize such interventions are essential. Herein, we investigated the association between sleep duration and AF risk using a prospective cohort study and a meta-analysis of epidemiological evidence.

Methods

Data of 6898 people, aged 30-84 years, from the Suita Study, were analyzed. AF was diagnosed during the follow-up by ECG, medical records, checkups, and death certificates, while a baseline questionnaire was used to assess sleep duration. The Cox regression was used to compute the hazard ratios (HRs) and 95% confidence intervals (CIs) of AF risk for daily sleep ≤ 6 (short sleep), ≥ 8 (long sleep), and irregular sleep, including night-shift work compared with 7 h (moderate sleep). Then, we combined our results with those from other eligible prospective cohort studies in two meta-analyses for the short and long sleep.

Results

In the Suita Study, within a median follow-up period of 14.5 years, short and irregular sleep, but not long sleep, were associated with the increased risk of AF in the age- and sex-adjusted models: HRs (95% CIs) = 1.36 (1.03, 1.80) and 1.62 (1.16, 2.26) and the multivariable-adjusted models: HRs (95% CIs) = 1.34 (1.01, 1.77) and 1.63 (1.16, 2.30), respectively. The significant associations between short and irregular sleep and AF risk remained consistent across different ages, sex, smoking, and drinking groups. However, they were attenuated among overweight and hypertensive participants. In the meta-analyses, short and long sleep durations were associated with AF risk: pooled HRs (95% CIs) = 1.21 (1.02, 1.42) and 1.18 (1.03, 1.35). No signs of significant heterogeneity across studies or publication bias were detected.

Conclusion

Short, long, and irregular sleep could be associated with increased AF risk. In the context of predictive, preventive, and personalized medicine, sleep duration should be considered in future AF risk scores to stratify the general population for potential personalized lifestyle modification interventions. Sleep management services should be considered for AF risk prevention, and these services should be individualized according to clinical characteristics and lifestyle factors.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-022-00275-4.

Abnormal Sleep Duration as Predictor for Cardiovascular Diseases: A Systematic Review of Prospective Studies

Methods

We searched the online database PubMed on 30 August 2020 for our data collection. We used the following keywords: sleep duration AND (cardiovascular disease OR cardiovascular event) AND (cohort OR prospective OR retrospective). We identified 653 studies, and after excluding studies that were published before 2015, we obtained 306 studies. After filtering the 306 studies through title and abstract screening and applying the inclusion and exclusion criteria, we further reviewed fourteen studies with full-text reading. We excluded three studies because of insufficient data required and included eleven studies in this systematic review.

Results

A total of 361,041 participants from ten studies were included in this systematic review. The incidence of hypertension, myocardial infarction, coronary artery disease, heart failure, cardiovascular events, and cardiovascular diseases in the short sleep duration group is 46.12%, 0.59%, 5.43%, 0.09%, 7.18%, 1.48%, and 6.8%, consecutively, while the incidence of hypertension, myocardial infarction, coronary artery disease, and heart failure in the long sleep duration group is 30.71%, 0.61%, 6.55%, 1.11%, and 6.04%, consecutively. Nine studies reported an association between sleep duration and cardiovascular diseases while one study reported no association. Seven studies reported that short sleep duration was significantly associated with CVD. Short sleep duration in this study was associated with hypertension and heart failure. Atrial fibrillation and coronary artery disease were associated with both short and long sleep duration.

Conclusion

Abnormal sleep duration (short and long sleep duration) may act as the predictor of cardiovascular diseases. The importance of having normal sleep duration should be stressed with other lifestyle modification to avoid the risk of getting cardiovascular diseases. However, further studies are needed to overcome the limitation of this systematic review.

Causal Roles of Sleep Duration in Osteoporosis and Cardiometabolic Diseases: A Mendelian Randomization Study

Sleep duration suggests some association with osteoporosis and cardiometabolic diseases, but it is unknown if these associations are causal or confounded. In this two-sample Mendelian randomization (MR) study, we included the largest genome-wide association studies (GWASs) associated with sleep duration and the outcome measures of osteoporosis and cardiometabolic diseases. Finally, 25 single nucleotide polymorphisms (SNPs) associated with short sleep duration and 7 SNPs associated with long sleep duration obtained the genome-wide significance (P < 5 × 10^-8) and were used as instrumental variables. Genetic predisposition to short sleep duration was strongly associated with increased risk of coronary artery disease (beta-estimate: 0.199, 95% confidence interval CI: 0.081 to 0.317, standard error SE:0.060, P value = 0.001) and heart failure (beta-estimate: 0.145, 95% CI: 0.025 to 0.264, SE:0.061, P value = 0.017), which were both confirmed by the sensitivity analyses. Both short and long sleep duration may reduce the estimated bone mineral density (eBMD, beta-estimate: -0.086, 95% CI: -0.141 to -0.031, SE:0.028, P value = 0.002 for short sleep duration; beta-estimate: -0.080, 95% CI: -0.120 to -0.041, SE:0.020, P value < 0.0001 for long sleep duration). There was limited evidence of associations between sleep duration and fracture, type 2 diabetes, atrial fibrillation, fasting glucose, fasting insulin, or HbA1c. This study provides robust evidence that short sleep duration is causally associated with high risk of coronary artery disease and heart failure and suggests that short sleep duration should be avoided to prevent these two cardiovascular diseases. Short and long sleep duration show some MR association with reduced eBMD, which indicates that both short and long sleep duration may be prevented to reduce the incidence of osteoporosis.

OUP accepted manuscript

Background

Evidence linking chronic kidney disease (CKD) and sleep duration is inconsistent. This study examined whether sleep duration is associated with a long-term risk of kidney function decline.

Methods

This retrospective, longitudinal cohort study included 82 001 participants who visited a primary care centre in Japan. Participants were categorized into CKD risk groups and sleep duration categories according to their self-reported average nightly sleep duration. The relationship between average nightly sleep duration and the incidence of composite renal outcome comprised a ≥40% reduction in estimated glomerular filtration rate (eGFR) from baseline and a decline in eGFR to <15 mL/min/1.73 m² was evaluated.

Results

The mean age and eGFR (±standard deviation) of the patient cohort were 45.8 (±12.4) years and 81.8 (±15.4) mL/min/1.73 m², respectively. A total of 41 891 participants (51.1%) were women. During the median follow-up of 5.1 years [interquartile range 2.2–9.6], 4214 (5.1%) participants achieved the composite renal outcome. Only the long and very long sleep durations (≥8 h/night) were associated with an increased incidence of the composite renal outcome compared with the reference duration (7 h/night) [adjusted odds ratio (OR) 1.22 and 1.44; 95% confidence interval (CI) 1.09–1.36 and 1.13–1.84, for long and very long sleep durations, respectively]. Furthermore, this association was significant for both long and very long sleep durations in the low CKD risk group but only for long sleep duration in the intermediate CKD risk group. The results of the sex-specific analysis showed that men had a decreased risk of achieving the composite renal outcome (OR 0.91; 95% CI 0.79–1.06), while there was an increased risk for women (OR 1.14; 95% CI 1.02–1.28).

Conclusions

Average sleep durations ≥8 h/night were associated with an increased incidence of poor renal outcomes over time. However, a longitudinal cohort study is required to confirm whether sleep duration can prevent poor renal outcomes.

Healthy Sleep Patterns and Risk of Incident Arrhythmias

BACKGROUND

Emerging evidence has linked sleep behaviors with the risk of cardiac arrhythmias. The various sleep behaviors are typically correlated; however, most of the previous studies only focused on the individual sleep behavior, without considering the overall sleep patterns.

OBJECTIVES

The purpose of this study was to prospectively investigate the associations between a healthy sleep pattern with the risks of cardiac arrhythmias.

METHODS

A total of 403,187 participants from UK Biobank were included. A healthy sleep pattern was defined by chronotype, sleep duration, insomnia, snoring, and daytime sleepiness. Weighted genetic risk score for atrial fibrillation was calculated.

RESULTS

The healthy sleep pattern was significantly associated with lower risks of atrial fibrillation/flutter (AF) (HR comparing extreme categories: 0.71; 95% CI: 0.64-0.80) and bradyarrhythmia (HR: 0.65; 95% CI: 0.54-0.77), but not ventricular arrhythmias, after adjustment for demographic, lifestyle, and genetic risk factors. Compared with individuals with a healthy sleep score of 0-1 (poor sleep group), those with a healthy sleep score of 5 had a 29% and 35% lower risk of developing AF and bradyarrhythmia, respectively. Additionally, the genetic predisposition to AF significantly modified the association of the healthy sleep pattern with the risk of AF (P interaction = 0.017). The inverse association of the healthy sleep pattern with the risk of AF was stronger among those with a lower genetic risk of AF.

CONCLUSIONS

Our results indicate that a healthy sleep pattern is associated with lower risks of AF and bradyarrhythmia, independent of traditional risk factors, and the association with AF is modified by genetic susceptibility.

Association of Sleep Duration With Atrial Fibrillation and Heart Failure: A Mendelian Randomization Analysis

Both short (<7 h per night) and long (≥9 h per night) sleep durations are related to atrial fibrillation (AF) and heart failure (HF), but their causality has not been confirmed. We applied Mendelian randomization (MR) approaches to estimate the causal association between genetically determined sleep duration and the risk of AF and HF. We performed two-sample MR analysis to obtain the effect of sleep duration on AF and HF. Instrumental variables were constructed using genetic variants known to be associated with continuous sleep duration, short sleep duration, and long sleep duration. MR estimates of the effect of sleep duration on AF and HF were derived based on two large meta-analyses of genome-wide association studies. The pooled MR estimate demonstrated a significant protective effect of continuous sleep duration on HF [odds ratio (OR) = 0.765, 95% confidence interval (CI) = 0.675–0.867; P = 2.64 × 10^–5] and a suggestive inverse association of continuous sleep duration with AF (OR = 0.893, 95% CI = 0.804–0.991; P = 0.034). In addition, the results showed a suggestive detrimental effect of short sleep duration on the risk of AF (OR = 1.108, 95% CI = 1.017–1.207; P = 0.019) and HF (OR = 1.136, 95% CI = 1.025–1.258; P = 0.015). Conversely, there is no significant evidence for the causal protective effect of long sleep duration on AF (OR = 0.956, P = 0.410) and HF (OR = 0.921, P = 0.202). This MR study indicated that genetically determined continuous sleep duration has a significant protective effect on HF and a suggestive inverse association with AF. Short sleep duration is positively associated with the risk of AF and HF. Nevertheless, there is no significant evidence for the causal protective effect of long sleep duration on AF and HF. Larger intervention studies are required to confirm the effectiveness of improving sleep on reducing the incidence of AF and HF.

Impact of Catheter Ablation on Sleep Quality and Relationship Between Sleep Stability and Recurrence of Paroxysmal Atrial Fibrillation After Successful Ablation: 24-Hour Holter-Based Cardiopulmonary Coupling Analysis

Background

Sleep fragmentation and sleep apnea are common in patients with atrial fibrillation (AF). We investigated the impact of radio‐frequency catheter ablation (RFCA) on sleep quality in patients with paroxysmal AF and the effect of a change in sleep quality on recurrence of AF.

Methods and Results

Of 445 patients who underwent RFCA for paroxysmal AF between October 2007 and January 2017, we analyzed 225 patients who had a 24‐hour Holter test within 6 months before RFCA. Sleep quality was assessed by cardiopulmonary coupling analysis using 24‐hour Holter data. We compared cardiopulmonary coupling parameters (high‐frequency coupling, low‐frequency coupling, very‐low‐frequency coupling) before and after RFCA. Six months after RFCA, the high‐frequency coupling (marker of stable sleep) and very‐low‐frequency coupling (rapid eye movement/wake marker) was significantly increased (29.84%–36.15%; P<0.001; and 26.20%–28.76%; P=0.002, respectively) while low‐frequency coupling (unstable sleep marker) was decreased (41.25%–32.13%; P<0.001). We divided patients into 3 tertiles according to sleep quality before RFCA, and the risk of AF recurrence in each group was compared. The second tertile was used as a reference; patients with unstable sleep (Tertile 3) had a significantly lower risk of AF recurrence (hazard ratio [HR], 0.32; 95% CI, 0.12–0.83 for high‐frequency coupling; and HR, 0.22; 95% CI, 0.09–0.58 for low‐frequency coupling).

Conclusions

Sleep quality improved after RFCA in patients with paroxysmal AF. The recurrence rate was significantly lower in patients who had unstable sleep before RFCA. These results suggest that RFCA can influence sleep quality, and sleep quality assessment before RFCA may provide a risk marker for recurrence after RFCA in patients with paroxysmal AF.

Night sleep duration and risk of each lipid profile abnormality in a Chinese population: a prospective cohort study

Background

To explore the associations between sleep duration and abnormalities in serum lipid levels in a Chinese population.

Methods

A prospective study was conducted with 34,260 participants from the general Chinese population. Sleep duration was categorized as ≤5, 6, 7, 8 or ≥ 9 h. Each lipid profile abnormality was defined according to the Chinese Guidelines for the Prevention and Treatment of Dyslipidemia in Adults (2016). The Cox proportional hazards model was used to assess the association between sleep duration and dyslipidemia.

Results

Compared with a 7 h sleep duration, long sleep duration (≥9 h) was significantly associated with low high-density lipoprotein cholesterol (HDL-C) levels (hazard ratio (HR): 1.24; 95% CI: 1.12–1.38). In subgroup analyses, the positive association between long sleep duration and low HDL-C level in men and in the different age groups was more pronounced than the association in women. No significant interactions were observed in the association between sleep duration and each abnormal serum lipid level by sex/age in the study population (P-interaction> 0.05).

Conclusions

These findings suggest that long sleep duration is associated with low HDL-C level among the Kailuan community population.

Associations between self-reported sleep characteristics and incident mild cognitive impairment: The Heinz Nixdorf Recall Cohort Study

Associations of sleep characteristics with mild cognitive impairment (MCI) have been examined in cross-sectional, but rarely in longitudinal studies. Incident MCI and sleep characteristics were assessed in 1,890 participants of the first and second follow-up of the Heinz Nixdorf Recall study, a population-based cohort study in Germany (age at first follow-up 50-80 years, mean follow-up 5.2 years). MCI was assessed with extensive cognitive tests. Sleep questionnaires including PSQI (Pittsburgh Sleep Quality Index) were used to assess sleep quality, sleep disturbances, time asleep, and time in bed. Relative risks (RR) of developing MCI when exposed to sleep characteristics were assessed in regression models adjusted for sociodemographic and cardiovascular risk factors. Poor sleep quality (PSQI > 5) (RR = 1.43, 95% CI: 1.12-1.82, fully adjusted, reference: PSQI ≤ 5) and difficulties initiating sleep (almost nightly versus never) (RR = 1.40, 0.94-2.08) were associated with incident MCI. For time in bed, the risk of MCI was increased for ≤ 5 hours (RR = 2.86, 1.24─6.60, reference:7 to <8 hours). In this longitudinal study with older participants, MCI risk was increased in persons with poor sleep quality, difficulties initiating sleep, and short time in bed.

Sleep Apnea and Heart

Scientific investigations in the past few decades have supported the important role of sleep in various domains of health. Sleep apnea is a highly prevalent yet underdiagnosed sleep disorder representing a valid cardiovascular risk factor, particularly for hypertension. While several studies have demonstrated the benefits of sleep apnea treatment on subclinical cardiovascular measures, there is a paucity of studies proving reduction of cardiovascular events and mortality. Sufficient and high-quality sleep is also important in the maintenance of cardiovascular health. Future investigations should focus on improving identification of patients at greatest risk of adverse cardiovascular s sequalae of sleep apnea and testing the therapeutic benefit of sleep apnea treatment in this vulnerable group.

Sleep Duration and Risk of Atrial Fibrillation: a Systematic Review

Background

Little is known about a possible association between sleep duration and the incidence of atrial fibrillation (AF), in healthy people. In this systematic review, we conducted a literature search to examine possible association between sleep duration and the incidence of AF.

Methods

Scientific databases (PubMed, Web of Knowledge and Embase) were searched using relevant Medical Subject Headings and keywords, to retrieve studies written in English and published until November 2017. Only observational studies were included. Since sleep duration categories were not consistent, it was feasible to run a meta-analysis.

Results

Six eligible studies were included. Long sleep duration (≥ 8 hours) was found to be associated with an increased risk of AF (adjusted hazard ratio (aHR) = 1.13; 95% CI: 1.00-1.27 and aHR= 1.5, 95% CI: 1.07-2.10) in two studies. One study reported that sleep duration less than 6 hours was associated with an increased risk of AF (aHR= 1.58, 95% CI: 1.18 -2.13) compared to sleeping for 6-7 hours. In two studies, mean sleep duration was lower in AF groups compared to the non-AF group. Insomnia was associated with an increased risk of AF in another study (aHR= 1.33, 95% CI: 1.25-1.41).

Conclusions

Unhealthy sleep duration, defined as either less than 6 hours or more than 8 hours, may be associated with an increased risk of AF.

Association of Short Sleep Duration and Atrial Fibrillation

BACKGROUND

Short sleep may be a risk factor for atrial fibrillation. However, previous investigations have been limited by lack of objective sleep measurement and small sample size. We sought to determine the association between objectively measured sleep duration and atrial fibrillation.

METHODS

All 31,079 adult patients undergoing diagnostic polysomnography from 1999 to 2015 at multiple sites within a large hospital network were identified from electronic medical records. Prevalent atrial fibrillation was identified by continuous ECG during polysomnography. Incident atrial fibrillation was identified by diagnostic codes and 12-lead ECGs. Logistic regression and Cox proportional hazards modeling were used to examine the association of sleep duration and atrial fibrillation prevalence and incidence, respectively, adjusting for age, sex, BMI, hypertension, coronary artery disease, cerebrovascular disease, peripheral vascular disease, heart failure, and sleep apnea severity.

RESULTS

We identified 404 cases of prevalent atrial fibrillation among 30,061 individuals (mean age ± SD, 51.0 ± 14.5 years; 51.6% women) undergoing polysomnography. After adjustment, each 1-h reduction in sleep duration was associated with a 1.17-fold (95% CI, 1.11-1.30) increased risk of prevalent atrial fibrillation. Among 27,589 patients without atrial fibrillation at baseline, we identified 1,820 cases of incident atrial fibrillation over 4.6 years median follow-up. After adjustment, each 1-h reduction in sleep duration was associated with a 1.09-fold (95% CI, 1.05-1.13) increased risk for incident atrial fibrillation.

CONCLUSIONS

Short sleep duration is independently associated with prevalent and incident atrial fibrillation. Further research is needed to determine whether interventions to extend sleep can lower atrial fibrillation risk.

Night Sleep Duration and Risk of Incident Anemia in a Chinese Population: A Prospective Cohort Study

The purpose was to study the association between sleep duration and the prevalence of anemia in Chinese people. There were 84,791 participants (men: 79.1%; women: 20.9%) aged 18–98 years in the prospective study. We divided the participants into five categories based on the individual sleep duration: ≤5 h, 6 h, 7 h(reference), 8 h, and ≥9 h. Anemia was defined based on hemoglobin <12 g/dL for men and <11 g/dL for women. The Cox proportional hazards model was used to assess the association between sleep duration and anemia. During median follow-up of 7.9 years, 2698 cases of anemia had occurred. The HRand (95% CI) of anemia (7 h as the reference group) for individuals reporting ≤5 h, 6 h, 8 h, and ≥9 h were 1.23(1.04–1.45), 1.26(1.11–1.44), 1.04(0.92–1.16) and 1.42(1.08–1.86), respectively. It showed that there was a significant interaction on the risk of anemia between sleep duration and sex in the secondary analysis (p < 0.001).The significant association between long sleepduration and anemia was found in women (HR, 2.29; 95% CI, 1.56–3.37), not in men(HR, 0.90; 95% CI, 0.60–1.34). Both short and long night sleep duration were associated with increased risk of anemia.