Association between daytime napping and stroke: A dose-response meta-analysis

Development and validation of a risk prediction model for frailty in older nappers

BACKGROUND

Frailty among older adults has received widespread attention from society, especially among nappers. The objective of this study was to develop a frailty prediction model for nappers.

METHODS

The data source was the China Health and Retirement Longitudinal Study, with a cohort of 1830 older nappers. We used the least absolute shrinkage and selection operator to screen the best predictors from multiple factors, logistic regression analysis to explore the best predictors of frailty in older nappers, and nomogram to establish a prediction model. A calibration curve was used to evaluate the precision of the model, and the predictive performance was assessed by analyzing the area under the characteristic and decision curves.

RESULTS

The prevalence of frailty among older nappers was 28.9 % (528/1830). Chronic diseases, physical activity, sleep quality, pain, fatigue, depression, nap duration, and nighttime sleep duration were the best predictive factors for frailty in older nappers. The area under the curve (AUC) in the training set was 0.751 (95 % confidence interval [CI] = 0.724-0.779) with a specificity of 0.662 and sensitivity of 0.711. The AUC in the validation set was 0.781 (95 % CI = 0.749-0.812) with a specificity of 0.730 and sensitivity of 0.714. The Hosmer-Lemeshow test values were both p > 0.05. The nomogram model showed good concordance and accuracy.

CONCLUSION

We constructed a nomogram that serves as a valuable and convenient instrument for assessing the prevalence of frailty among older nappers.

Midday napping duration and risk of stroke: A prospective study in China

BACKGROUND

Evidence on the potential effects of midday napping on risk of stroke in Chinese populations remains limited.

OBJECTIVES

We aimed to prospectively investigate the association between midday napping and risk of subsequent stroke and stroke subtypes in the Kailuan study.

METHODS

Midday napping duration was obtained from a self-reported questionnaire. Incident stroke cases from baseline (2014) to December 31, 2020 were confirmed by review of medical records. The association of midday napping duration with risk of incident stroke and subtypes was examined using a Cox regression model, adjusting for potential confounders. We further investigated the joint effects of nocturnal sleep duration and midday napping on the risk of stroke.

RESULTS

A total of 96,899 individuals (21.0 % women; 51.9 ± 14.0 years) were included. During an average follow-up of 5.62 ± 0.69 years, 2539 incident stroke cases were documented. After adjusting for potential confounders, we found that participants with a midday napping duration of >60 min/day had higher risk of incident stroke (adjusted HR: 1.23; 95 % CI: 1.07, 1.42), compared with those without midday napping. Furthermore, significant joint effects were found in both nocturnal sleep duration (P-interaction=0.04) and snoring status (P-interaction= 0.005) on the association between midday napping duration and the risk of incident stroke, especially for participants who napped >60 min/day and slept ≤7 h/night compared with those who slept 7-8 h/night and did not take a nap, or those who napped >60 min/day and snored compared with those who did not take a nap and snore.

CONCLUSIONS

We found that prolonged midday napping (>60 min/day) was associated with higher risk of stroke and the association was stronger among those with shorter nocturnal sleep duration or those who snored.

To nap or not? Evidence from a meta-analysis of cohort studies of habitual daytime napping and health outcomes

Habitual daytime napping is a common behavioral and lifestyle practice in particular countries and is often considered part of a normal daily routine. However, recent evidence suggests that the health effects of habitual daytime napping are controversial. We systematically searched PubMed, Web of Science, Embase, and Cochrane Library databases from inception to March 9, 2024, to synthesize cohort studies of napping and health outcome risk. A total of 44 cohort studies with 1,864,274 subjects aged 20-86 years (mean age 56.4 years) were included. Overall, habitual napping increased the risk of several adverse health outcomes, including all-cause mortality, cardiovascular disease, metabolic disease, and cancer, and decreased the risk of cognitive impairment and sarcopenia. Individuals with a napping duration of 30 min or longer exhibited a higher risk of all-cause mortality, cardiovascular disease, and metabolic disease, whereas those with napping durations less than 30 min had no significant risks. No significant differences in napping and health risks were observed for napping frequency, percentage of nappers, sample size, sex, age, body mass index, follow-up years, or comorbidity status. These findings indicate that individuals with a long napping duration should consider shortening their daily nap duration to 30 min or less.

Long daytime napping: A silent danger for hypertensive individuals

BACKGROUND AND PURPOSE

Hypertension significantly contributes to stroke. Previous research has indicated a connection between daytime napping and stroke. Research on the connection between daytime napping duration and first stroke in hypertensive individuals is lacking nevertheless.

METHODS

This research, which ran from 24 August 2013 to 31 December 2022, recruited 11,252 individuals with hypertension and without a history of stroke from the China Stroke Primary Prevention Trial. To determine the relationship between daytime napping duration and stroke onset in hypertensive individuals, we conducted analyses for threshold effects, multivariate-adjusted Cox proportional hazard regression models, and Kaplan-Meier survival curves.

RESULTS

The duration of daytime napping (<75 min) was positively correlated with stroke risk; beyond 75 min, the risk did not increase further. When compared to hypertensive individuals who napped for 1-30 min, daytime napping 31-60 min (hazard ratio [HR] = 1.27, 95% confidence interval [CI] = 1.06-1.53) and >60 min (HR = 1.37, 95% CI = 1.14-1.65) were substantially related with a greater risk of first stroke. Additionally, this correlation was absent in cases of hemorrhagic stroke, but present in cases of ischemic stroke, specifically for hypertensive individuals who napped for 31-60 min or >60 min (p < 0.05). Kaplan-Meier survival curves displayed that hypertensive individuals who extended daytime napping had an elevated incidence of stroke.

CONCLUSIONS

Hypertensive individuals who take longer daytime naps (>30 min) are at an elevated risk of stroke onset, particularly ischemic stroke, irrespective of other factors.

Daytime Napping, Incident Atrial Fibrillation, and Dynamic Transitions With Dementia

Background

Associations between napping and incident atrial fibrillation (AF) remain unknown, and few studies have accounted for dynamic transitions between AF and dementia.

Objectives

The purpose of this study was to evaluate associations between napping with incident AF and the dynamic transitions of AF and dementia, as well as the mediation pathway of left ventricular (LV) size and function.

Methods

A total of 476,588 participants from UK Biobank were included. Napping frequency and other sleep behaviors were evaluated. Incident AF, dementia, and mortality were ascertained via linkage to external registry databases. LV size and function indices were obtained from cardiovascular magnetic resonance imaging phenotypes. A multistate survival analysis was conducted to examine daytime napping in relation to dynamic transitions. Weighed AF genetic risk score was calculated.

Results

Frequent daytime napping, compared to never/rarely napping, was associated with a 1.17-fold AF risk (HR: 1.17; 95% CI: 1.12-1.22), which persisted after controlling for other sleep behaviors. Genetic predisposition significantly modified associations between napping and AF (P for interaction <0.001), with stronger associations observed in those of low and moderate genetic risk. LV ejection fraction significantly mediated 26.2% (95% CI: 4.2%-74.1%) of associations between napping and AF. Frequent napping was also associated with a 1.27-fold risk of transition from AF to comorbidity of AF and dementia.

Conclusions

Our findings highlight the potential importance of screening for napping in view of the association with incident AF and dementia. Routine evaluations of the LV ejection fraction could be warranted to timely identify early indications of AF onset among habitual nappers.

2024 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2024 AHA Statistical Update is the product of a full year's worth of effort in 2023 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. The AHA strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional global data, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Daytime napping and coronary heart disease risk in adults: a systematic review and dose-response meta-analysis

PURPOSE

The present study investigated the association between daytime napping and coronary heart disease (CHD) risk among adults.

METHODS

Articles were detected by using PubMed, ISI Web of Science, and Scopus databases until November 8th, 2021. The relevant data were found among the eight included articles and were pooled for meta-analysis in adult participants via a random-effects model.

RESULTS

Among 167,025 adults, the results revealed that daytime napping was associated with an enhanced risk of CHD (risk ratios [RR] = 1.30; 95% CI: 1.06, 1.60; p < 0.001). Subgroup analysis by daytime napping duration also indicated that daytime napping for at least 1 h had three times higher influence on the enhanced risk of CHD (RR = 1.34; 95% CI: 1.14, 1.58; p < 0.001) than that of daytime napping for less than 1 h (RR = 1.10; 95% CI: 1.02, 1.19; p = 0.014). In addition, subgroup analysis by region illustrated that daytime napping was linked with an enhanced risk of CHD in Chinese (RR = 1.41; 95% CI: 1.19, 1.66; p < 0.001), but not in European or American populations. Furthermore, the subgroup analysis of napping duration and risk of CHD suggested that their relation was significant just in those studies that controlled for depressive symptoms (RR = 1.52; 95% CI: 1.29, 1.80; p < 0.001, n = 3) and night sleep duration (RR = 1.42; 95% CI: 1.21, 1.66; p < 0.001, n = 5). The linear dose-response meta-analysis revealed that each 15-min increase in daytime napping was related with a 5% higher risk of CHD (RR = 1.05; 95% CI: 1.02, 1.08; I2 = 58.7%; p < 0.001). Furthermore, nonlinear dose-response meta-analysis revealed a positive linear relationship between daytime napping and CHD risk in adults (p nonlinearity = 0.484, p dose-response = 0.003).

CONCLUSION

Results showed that daytime napping was related with an increased risk of CHD in adults. The evidence from this study suggests that the public should be made conscious of the adverse outcomes of long daytime napping for CHD, notably among the Chinese population. Additional studies are required to confirm potential links between CHD risk and daytime napping.

The independent and combined association of napping and night sleep duration with stroke in Chinese rural adults

BACKGROUND

Inappropriate sleep duration is a potential cause of stroke. But the effect of napping on stroke risk remains controversial and the interaction between night sleep and napping duration remains unclear. The objective of this study was to examine the independent and combined effects of napping and nocturnal sleep duration on stroke.

METHODS

Subjects were derived from a rural cohort study in Henan. The Pittsburgh Sleep Quality Index (PSQI) was applied to identify nap duration and nocturnal sleep duration. Binary logistic regression was employed to indicate the dose-response relationships between naps, nocturnal sleep, total 24-h sleep duration, and stroke.

RESULTS

Among the 37,341 participants (14,485 men), 2600 suffered from a stroke. The odds ratios (ORs) and 95% confidence level (CI) for stroke in the fully adjusted model were 1.37 (1.13-1.65) for men nappers compared to non-nappers. Compared to 7-8 h of sleep per day, night sleep durations < 6 h and ≥ 9 h and 24-h sleep duration ≥ 10 h were linked to increased odds of stroke in men. The ORs (95%CI) were 1.34 (1.06-1.69) in nocturnal sleep duration < 6 h, 1.30 (1.06-1.59) in nocturnal sleep duration ≥ 9 h, and 1.40 (1.15-1.71) in 24-h sleep duration ≥ 10 h in men. In addition, long naps and prolonged nocturnal sleep duration have a joint effect on stroke in the fully adjusted model.

CONCLUSION

The napping duration and nocturnal sleep duration have independently and jointly effects on stroke in rural populations. More research is required to explore the underlying mechanisms for this relationship.

CLINICAL TRIAL REGISTRATION

The Henan Rural Cohort Study has been registered on the Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699) ( http://www.chictr.org.cn/showproj.aspx?proj=11375 ).

Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2023 Statistical Update is the product of a full year's worth of effort in 2022 by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. The American Heart Association strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional COVID-19 (coronavirus disease 2019) publications, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Association between daytime nap duration and risks of frailty: Findings from the China Health and Retirement Longitudinal Study

Introduction

Night sleep duration and total sleep duration are associated with frailty. However, the association between daytime nap duration and the risks of frailty has not been explored thoroughly.

Methods

This study used data from the China Health and Retirement Longitudinal Study (CHARLS). Participants aged 60 years and older at baseline were included in this study. Individuals with daytime nap duration were categorized into four groups: no napping, short napping (< 30 min), moderate napping (30-89 min), and extended napping (≥90 min). Frailty was assessed using a modified Physical Frailty Phenotype (PFP) scale. Non-frail participants at baseline were followed up for 4 years. The association between nap duration and risks of frailty at baseline and incident frailty was evaluated by logistic regression and discrete-time Cox regression analyses, respectively.

Results

In total, 5,126 participants were included in this study. For individuals with night sleep duration of ≥9 h, short nappers showed higher odds [odds ratio (OR) = 4.08, 95% confidence interval (CI): 1.30-12.78] for frailty compared with non-habitual nappers at baseline, while moderate nappers were less likely to be frail (OR = 0.18, 95% CI: 0.04-0.73). In the follow-up study, short nappers showed higher risks for frailty compared with participants of the no napping group with night sleep duration of < 6 h [hazard ratio (HR) = 1.91, 95% CI: 1.07-3.43] or 6-9 h (HR = 1.97, 95% CI: 1.18-3.30). Compared with short nappers, older adults with extended napping (HR = 0.41, 95% CI: 0.22-0.77) showed lower risks for frailty in those with night sleep duration of 6-9 h. For individuals with night sleep duration of ≥9 h, moderate napping (HR = 0.20, 95% CI: 0.05-0.77) decreased the risks for frailty compared with short napping.

Conclusion

Among older adults with night sleep duration of < 9 h, short nappers posed higher risks for frailty compared with non-habitual nappers. Extended naps for those with a night sleep duration of 6-9 h or moderate naps for those with night sleep duration of ≥9 h could lower the risk of frailty compared with short naps. Future studies on the timing, purpose, frequency, and quality of daytime napping and objectively measured nap duration are needed to explore the association between daytime napping and risks of frailty.

Trends in prevalence of short sleep duration and trouble sleeping among US adults, 2005-2018

STUDY OBJECTIVES

To determine trends in prevalence of short sleep duration and trouble sleeping among US adults from 2005 to 2018, and to assess how sleep trends vary by sex and race/ethnicity.

METHODS

Seven cycles of the National Health and Nutrition Examination Survey data between 2005-2006 and 2017-2018 were analyzed. Trouble sleeping and sleep duration were self reported. Short sleep duration was defined as sleep duration ≤6 hr. Age-standardized prevalence of reporting trouble sleeping to a health care provider and short sleep duration were estimated among the overall US adult population, and by sex and race/ethnicity.

RESULTS

From 2005 to 2014, the age-adjusted prevalence of short sleep duration remained similar in the overall population (p for trend >0.05). Non-Hispanic Black people had the highest prevalence of short sleep duration among all race/ethnicity groups in all seven cycles. The prevalence of short sleep duration appears lower in 2015-2018 than in 2005-2014 due to different measurement methods applied. However, from 2005 to 2018, there were increasing trends in age-adjusted prevalence of reporting trouble sleeping to a health care provider in the overall population, among both men and women, and all race/ethnicity groups (p for trend <0.05). Among all the race/ethnicity groups, non-Hispanic White people had the highest prevalence of reporting trouble sleeping to a healthcare provider.

CONCLUSION

Findings depict the persistence of sleep-related issues in the United States and possible risk factors, as well as racial disparities.

Association of sleep duration and napping with stroke mortality in older Chinese: A 14-year prospective cohort study of the Guangzhou Biobank Cohort study

STUDY OBJECTIVE

Evidence regarding the association of short sleep duration and napping with stroke remains limited and controversial. We examined the association of sleep duration and napping with risk of stroke mortality in an older Chinese cohort.

METHODS

Sleep duration and daytime napping were assessed by face-to-face interview during 2003-2008. Information of causes of death until April 30, 2021 was collected via record linkage with the Death Registry. Cox regression was used to calculate the hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

Of 27,254 participants aged average 62.0 (standard deviation = 7.1) years, 818 stroke deaths occurred within 388,798 person-years (mean = 14.3 years) of follow-up. A U-shaped relation between sleep duration and risk of stroke mortality was observed. Participants with short (≤5 h/day) or long sleep duration (≥9 h/day) showed higher risks of total stroke mortality, with adjusted HRs (95% CIs) being 1.27 (1.01-1.59) and 1.37 (1.07-1.75), respectively. However, non-significant association of short or long sleep duration with hemorrhagic or ischemic stroke mortality was found. The associations of short and long sleep duration with total stroke mortality were more pronounced in those with hypertension (P for interaction with hypertension = 0.01), with HRs (95% CIs) being 1.37 (1.04-1.82) and 1.77 (1.33-2.36), respectively. No association between napping and risk of stroke mortality was found.

CONCLUSIONS

Both short and long sleep duration, but not daytime napping, were associated with higher risk of stroke mortality. Public health messages to encourage good sleep hygiene may be important, especially for people with hypertension.

Daytime naps and depression risk: A meta-analysis of observational studies

Background

The relationship between daytime napping and depression remains debatable. Thus, a meta-analysis in this study was conducted to evaluate the relationship between daytime napping and depression.

Methods

The PubMed, Embase, Web of Science, and China National Knowledge Infrastructure databases were searched up to February 2022, and the reference lists of the included studies were also retrieved. A random-effects model was used to estimate the combined effect size.

Results

Nine studies with 649,111 participants were included in the final analysis. The pooled odds ratio (OR) was 1.15 (95% confidence interval: 1.01-1.31) with a significant heterogeneity (I ² = 91.3%, P for heterogeneity <0.001), and the results demonstrated an increased risk of depressive symptoms among daytime nappers. Visual inspection of the funnel plot and Egger's and Begg's tests identified no obvious evidence of publication bias.

Conclusion

This meta-analysis indicates that daytime naps are a predictor of depression. The effects of daytime napping on depression may vary depending on the characteristics of people, the pattern of naps, and the individual's sleep experience. The findings may have significant implications for future research on depression.

Association of Nap Frequency With Hypertension or Ischemic Stroke Supported by Prospective Cohort Data and Mendelian Randomization in Predominantly Middle-Aged European Subjects

BACKGROUND AND PURPOSE

The aim of this study was to investigate the association between daytime napping frequency and the incidence of essential hypertension or stroke as well as to validate causality in this relationship via Mendelian randomization (MR).

METHODS

We conducted Cox regression analysis on 358 451 participants free of hypertension or stroke from UK Biobank. To validate the results of the observational analysis, we conducted a 2-sample MR for daytime napping frequency (123 single-nucleotide polymorphisms) with essential hypertension in FinnGen Biobank, stroke, and ischemic stroke in MEGASTROKE consortium and performed a corresponding 1-sample MR on the UK Biobank data.

RESULTS

Compared with never napping, usually napping was associated with a higher risk of essential hypertension (hazard ratio, 1.12 [95% CI, 1.08-1.17]), stroke (hazard ratio, 1.24 [95% CI, 1.10-1.39], and ischemic stroke (hazard ratio, 1.20 [95% CI, 1.05-1.36]) in our prospective observational analysis. Both the 1-sample and 2-sample MR results indicated that increased daytime napping frequency was likely to be a potential causal risk factor for essential hypertension in FinnGEN (odds ratio, 1.43 [95% CI, 1.06-1.92]) and UK Biobank (odds ratio, 1.40 [95% CI, 1.28-1.58]). The 2-sample MR results supported the potential causal effect of nap frequency on ischemic stroke in MEGASTROKE (odds ratio, 1.29 [95% CI, 1.04-1.62]).

CONCLUSIONS

Prospective observational and MR analyses provided evidence that increased daytime nap frequency may represent a potential causal risk factor for essential hypertension. The potential causal association of increased nap frequency with ischemic stroke was supported by 2-sample MR and prospective observational results.

Daytime napping and cardiovascular risk factors, cardiovascular disease, and mortality: A systematic review

Associations between night sleep duration and cardiovascular risk factors in adults have been well documented. However, the associations for daytime napping remain unclear. In this review, six databases were searched for eligible publications to April 8, 2022. A total of 11 articles were identified for umbrella review on the association of daytime napping with diabetes, metabolic syndrome (MetS), cardiovascular disease (CVD), and mortality in adults, 97 for systematic review on the association with CVD and several CVD risk factors. Our umbrella review showed that the associations of daytime napping with diabetes, MetS, CVD, and mortality in most meta-analyses were mainly supported by weak or suggestive evidence. Our systematic review showed that long daytime napping (≥1 h/d) was associated with higher odds of several CVD risk factors, CVD, and mortality, but no significant association was found between short daytime napping and most of the abovementioned outcomes. Our dose-response meta-analyses showed that daytime napping <30 min/d was not significantly associated with higher odds of most CVD risk factors and CVD among young and middle-aged adults. However, among older adults aged >60 years, we observed significant dose-response associations of daytime napping with higher odds of diabetes, dyslipidemia, MetS, and mortality starting from 0 min/d.