Influence of lung function and sleep-disordered breathing on stroke: a community-based study

Lung function indices do not affect the incidence of coronary heart disease in patients with sleep-disordered breathing

BACKGROUND

Currently, it's unclear whether sleep-disordered breathing (SDB) and reduced lung function could synergistically increase the incidence of coronary heart disease (CHD). Furthermore, the predictive value of different lung function indices for the incidence of CHD remains unknown.

METHODS

We enrolled 3749 participants from the Sleep Heart Health Study (SHHS) to conduct a retrospective study. The individuals were divided into the SDB and non-SDB subgroups according to Apnoea-Hypopnoea Index (AHI). Cox regression models were used to evaluate the association between lung function and CHD. We also conducted a ROC analysis to assess the predictive value of different lung function indices.

RESULTS

512 cases of CHD were identified during an average of 10.40 years of follow-up in participants without CVD at baseline. We observed that lung function was a better predictor of CHD in non-SDB participants compared with SDB participants. Reduced lung function was associated with a higher risk of CHD in participants without SDB, while the inverse association became non-significant in participants with SDB. Furthermore, the incremental contribution of lung function to CHD diminished with increasing severity of SDB.

CONCLUSION

We need to focus more on the lung function of individuals without SDB rather than those with SDB to reduce the risk of CHD.

Sleeping Late Increases the Risk of Myocardial Infarction in the Middle-Aged and Older Populations

Objective: Sleep has a significant influence on the incidence of myocardial infarction (MI). The purpose of this study was to investigate the association between sleep timing including bedtime, wake-up time and sleep midpoint, and the incidence of MI.

Methods: A total of 4,576 patients (2,065 men, 2,511 women; age 63.4 ± 11.0 years) were selected from the Sleep Heart Health Study. Sleep timings on weekdays and weekends were recorded or calculated based on the sleep habits questionnaire completed by the participants at baseline. Bedtime was divided into 10:00 PM and before, 10:01 PM−11:00 PM, 11:01 PM−12:00 AM, and later than 12:00 AM. Cox proportional hazards regression analysis was used to examine the relationship between sleep timings and MI.

Results: Participants with a weekday bedtime later than 12:00 AM, between 11:01 PM−12:00 AM, and 10:00 PM or before had a higher incidence of MI than those with a bedtime between 10:01 PM and 11:00 PM (9.2% vs. 7.0% vs. 6.9% vs. 5.1%, respectively; P = 0.008). Multivariable Cox regression analysis showed that sleeping on weekdays later than 12:00 AM was associated with an increased risk of incident MI after adjusting for potential covariates (hazard ratio, 1.628; 95% confidence interval, 1.092–2.427; P = 0.017). However, there was no significant association between late bedtime on weekends and MI. In addition, no significant association of late wake-up time and delayed sleep midpoint on both weekdays and weekends with the incidence of MI was observed.

Conclusion: Sleeping late on weekday (>12:00 AM) independently increased the risk of MI. This finding emphasizes the importance of a proper bedtime for the maintenance of the health of the cardiovascular system.

Sleep Timing May Predict Congestive Heart Failure: A Community-Based Cohort Study

Background

Previous studies have suggested that sleep timing is associated with cardiovascular risk factors. However, there is no evidence on the relationship between sleep timing and congestive heart failure (CHF). We aimed to examine this relationship in this study.

Methods and Results

We recruited 4765 participants (2207 men; mean age, 63.6±11.0 years) from the SHHS (Sleep Heart Health Study) database in this multicenter prospective cohort study. Follow‐up was conducted until the first CHF diagnosis between baseline and the final censoring date. Sleep timing (bedtimes and wake‐up times on weekdays and weekends) was based on a self‐reported questionnaire. Cox proportional hazard models were constructed to investigate the association between sleep timing and CHF. During the mean follow‐up period of 11 years, 519 cases of CHF (10.9%) were reported. The multivariable Cox proportional hazards models revealed that participants with weekday bedtimes >12:00 am (hazard ratio [HR], 1.56; 95% CI, 1.15–2.11; P=0.004) and from 11:01 pm to 12:00 am (HR, 1.25; 95% CI, 1.00–1.56; P=0.047) had an increased risk of CHF compared with those with bedtimes from 10:01 pm to 11:00 pm. After stratified analysis, the association was intensified in participants with a self‐reported sleep duration of 6 to 8 hours. Furthermore, wake‐up times >8:00 am on weekdays (HR, 1.53; 95% CI, 1.07–2.17; P=0.018) were associated with a higher risk of incident CHF than wake‐up times ≤6:00 am.

Conclusions

Delayed bedtimes (>11:00 pm) and wake‐up times (>8:00 am) on weekdays were associated with an increased risk of CHF.

Longitudinal Analysis of Lung Function in Pregnant Women with and without Asthma

BACKGROUND

Spirometry is commonly used to assess and monitor lung function. It may also be a useful tool to monitor maternal health during pregnancy. However, large studies examining lung function across gestation are limited. Also, whether spirometry values follow the same pattern during pregnancy in women with and without asthma is unknown.

OBJECTIVE

To investigate the effect of advancing gestation, and its interaction with asthma, on lung function in a large well-defined cohort of pregnant women.

METHODS

Data were obtained from prospective cohorts involving women with (n = 770) and without (n = 259) asthma (2004-2017), recruited between 12 and 22 weeks' gestation. Lung function (forced vital capacity [FVC], FEV₁, FEV₁:FVC%) was assessed periodically during pregnancy using spirometry. Multilevel mixed-effect regression models were used to assess changes in lung function over gestation.

RESULTS

Asthma had a significant effect on baseline lung function (FEV₁%, -9%; FVC%, -3%; FEV₁:FVC%, -4%). FVC% decreased with advancing gestation (-0.07%/wk; 95% CI, -0.10 to -0.04]), as did FEV₁%, but only among those without asthma (women without asthma: -0.14%/wk, 95% CI, -0.22 to -0.06%; compared with women with asthma: 0.02%/wk, 95% CI, -0.01 to 0.06). FEV₁:FVC% remained relatively stable for women without asthma (0.03%/wk; 95% CI, -0.08 to 0.02), but increased for women with asthma (0.06%/wk; 95% CI, 0.04 to 0.16).

CONCLUSIONS

Data suggest that advancing gestation negatively affects FVC% and FEV₁%. This is consistent with extrapulmonary restriction from advancing pregnancy. Yet, the presence of asthma altered the trajectories of FEV₁% and FEV₁:FVC%. Optimal asthma management during pregnancy might have opposed the negative effects of gestation on lung function.

Influence of rapid eye movement sleep on all-cause mortality: a community-based cohort study

Introduction: Although the proportion and duration of rapid eye movement (REM) sleep are correlated with neurological and cardiovascular diseases, whether REM sleep is associated with all-cause mortality in community-based populations remains unknown.

Methods: A prospective study was performed within the Sleep Heart Health Study (SHHS, Registration NO. NCT00005275). Total sleep time, sleep efficiency, and REM sleep were measured using polysomnography. Cox proportional hazards regression models were used to estimate the association of the REM sleep with all-cause mortality.

Results: Over a mean follow-up period of 11.0 ± 3.1 y, 1234 individuals (21.9%) died. In the entire population, reduced REM sleep was significantly associated with increasing all-cause mortality. After adjustment for age, sex, race, body mass index, smoking status, total cholesterol, triglycerides, high-density lipoprotein, history of diabetes and hypertension, and the apnea–hypopnea index, the duration and proportion of REM sleep were found to be significantly associated with all-cause mortality when the lowest and the highest REM quartile groups were compared (hazard ratio, 95% confidence interval: 1.727, 1.434-2.079; 1.545, 1.298-1.839; respectively).

Conclusion: The proportion and duration of REM sleep are negatively associated with all-cause mortality. This finding emphasizes the importance of personalized sleep management in community-based populations.

Association of daytime napping with incident stroke in middle-aged and older adults: a large community-based study

BACKGROUND AND PURPOSE

There are conflicting reports on the association between daytime napping and incident stroke. This study was designed to investigate the relationship between daytime napping and stroke within a community-based cohort.

METHODS

The present prospective study was based on the Sleep Heart Health Study. Napping habits were assessed with a self-reported Sleep Habits Questionnaire. Participants with napping habits of different durations and frequencies were followed up until the first stroke occurred or the final censoring date. Cox proportional hazards models were used to estimate the relationship between napping habits and stroke.

RESULTS

A total of 4757 participants (2219 men, mean age 63.6 ± 11.1 years) were enrolled in this study. Compared with those taking no naps, multivariate proportional hazards models analysis indicated that individuals taking naps with a duration of >60 min [hazard ratio (HR), 2.460; 95% confidence interval (CI), 1.538-3.934] had a higher risk of stroke. There was also an increased risk of stroke among participants taking naps daily (HR, 1.563; 95% CI, 1.059-2.307) or five to six times/week (HR, 1.548; 95% CI, 1.026-2.335). After combining napping durations and frequencies, regular long naps (HR, 1.903; 95% CI, 1.182-3.065) and regular short naps (HR, 1.451; 95% CI, 1.010-2.084) were independent risk factors for incident stroke.

CONCLUSION

Daytime napping with a long duration (>30 min) or a high frequency (≥5 times/week) may increase the risk of stroke.

Genetic correlations and causal inferences in ischemic stroke

BACKGROUND AND PURPOSE

Considerable studies have reported inconsistent relationships between ischemic stroke and a large number of factors. These uncertainties may reflect the susceptibility to confounding in observational studies. We aimed to assess genetic correlations and causal relationships between ischemic stroke and diverse phenotypes.

METHODS

Summary-level data for ischemic stroke (34,217 cases and 406,111 controls) from the MEGASTROKE consortium were used as the outcome. Exposures were derived from two GWAS statistics curated databases. We explored the genetic correlations and causalities between hundreds of traits and ischemic stroke, using linkage disequilibrium score regression and Mendelian randomization (MR), respectively. Multiple sensitivity analyses were also performed.

RESULTS

Genetic correlation analyses reflected genetic overlaps between ischemic stroke and physical activity, cardiometabolic factors, smoking, and lung function. Applying MR, we found suggestive evidence that genetic predisposition to higher concentration of low-density lipoprotein particles (LDL.P) and cholesterol carried in different sizes of LDL.P (LDL.C) were associated with higher risk of ischemic stroke, particular large artery stroke. The strongest effect was observed for small LDL.P in large artery stroke (OR 1.31, 95% CI 1.09-1.56, p = 0.003). The results were overall robust for sensitivity analyses. We further observed significant positive associations of genetically predicted LDL.P and LDL.C with coronary artery disease and myocardial infarction.

CONCLUSIONS

Shared genetic overlaps might exist between ischemic stroke and physical activity, cardiometabolic factors, smoking, and lung function. We provided suggestive evidence for a potential causal role of LDL.P and LDL.C in ischemic stroke, particularly in large artery stroke. Future researches are required to confirm these findings.

Neck Circumference is Associated with Incidence of Angina Pectoris in a Large Community-Based Population

BACKGROUND

Previous studies have found that neck circumference (NC) is associated with cardiovascular disease risk factors. This study investigated the relationship between NC and the incidence of angina pectoris (AP).

METHODS

Altogether 4821 participants (2212 males and 2609 females) from the Sleep Heart Health Study (SHHS) with a mean age of 63.4±11.0 years were selected in this study. Anthropometric measurements, including NC, waist circumference (WC), hip circumference (HC), and body mass index (BMI), were collected at baseline. AP was defined as the first occurrence between baseline and 2011. Linear and logistic regression analysis was used to explore the association between NC and incidences of AP.

RESULTS

There was a significant difference in NC between AP and controls in both male (41.1±3.1 cm vs 40.3±3.2 cm; p<0.001) and female (35.2±3.1 cm vs 34.9±2.9 cm; p=0.006). Multivariable linear regression analysis showed that NC (every cm increase) was independently associated with the incidence of AP in both male (odds ratio [OR] 1.067; 95% confidence interval [CI] 1.035-1.100; p<0.001) and female (OR 1.067; 95% CI 1.035-1.101; p<0.001).

CONCLUSION

NC was significantly associated with the incidence of AP in both male and female. The role of NC in the incidence of AP is worthy of further investigation.

Incidence of Stroke and Mortality in Chinese Patients with Sleep-Breathing Disorders: A Clinical Population-Based (CPB) Study

BACKGROUND Sleep-breathing disorders are associated with inflammatory, metabolic, and vascular diseases. The objective of this study was to investigate the incidence of stroke and death in patients with sleep-breathing disorders. MATERIAL AND METHODS The anthropometric characteristics, demographic data, and incidence of stroke of 1492 Chinese patients with mild, moderate, or severe sleep apnea were collected. The apnea-hypopnea index was used to define sleep-breathing disorders. Imaging modalities were used to validate the diagnosis of stroke. Death during hospitalization or during follow-up was noted. Multivariate analysis was performed for the incidence of stroke and mortality at the 95% of confidence level. RESULTS Among enrolled patients, 401 (27%) patients had at least 1 event of stroke. Patients who had at least 1 event of stroke were more likely to be younger (p<0.0001), female (p=0.0013), and to have comorbidities. Among enrolled patients, 127 died due to stroke or other diseases. Sixteen of the patients who died had no stroke event(s) and 111 patients who died had at least 1 event of stroke. Stroke events (p=0.023) and biomedical burden of patients were associated with the death of patients with sleep-breathing disorders. CONCLUSIONS Age, sex, and the other existing disease(s) of patients with sleep-breathing disorders may be associated with stroke event(s). Also, stroke event(s) and comorbidities may be associated with mortality in this Chinese population.

Impact of Lung Function and SDB on Incident Myocardial Infarction and Heart Failure: A Community-based Study

PURPOSE

To investigate whether lung function, especially when complicated with SDB, has an increased risk for myocardial infarction (MI) and congestive heart failure (CHF).

METHODS

A prospective study was performed within the Sleep Heart Health Study (SHHS). A total of 4161 individuals were followed up for an average of 10.91 years. Forced vital capacity (FVC), forced expiratory volume in one second (FEV₁) and the predicted value of FVC and FEV₁ were measured to evaluate lung function. The primary outcomes were the MI and CHF. Cox regression analysis was used to investigate the association between reduced lung function and the incidence of MI or CHF. In subgroup analysis, all the individuals were divided into Apnoea-Hypopnoea Index (AHI) < 5 subgroup and AHI ≥ 5 subgroup to explore the relationship.

RESULTS

Lung function were inversely associated with the incidence of MI or CHF. The hazard ratio (HR) and 95% confidence interval (95% CI) for MI and CHF were 0.658 (0.543-0.797) and 0.792 (0.673-0.933) for every 1 L increase in FVC, 0.715 (0.567-0.902) and 0.738 (0.605-0.900) for every 1 L increase in FEV₁, 0.986 (0.979-0.993) and 0.989 (0.983-0.995) for every 1% increase in FEV₁/pre%, and 0.994 (0.988-0.999) and 0.991 (0.987-0.996) in FVC/pre%, respectively. In addition, the association of lung function with MI and CHF was more prominent in the subgroup with AHI ≥ 5.

CONCLUSIONS

Lung function may be associated with incident MI and CHF in this large community cohort of middle-aged and older adults, especially in those with SDB.

New frontiers in the treatment of comorbid cardiovascular disease in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a disease characterised by persistent airflow limitation that is not fully reversible and is currently the fourth leading cause of death globally. It is now well established that cardiovascular-related comorbidities contribute to morbidity and mortality in COPD, with approximately 50% of deaths in COPD patients attributed to a cardiovascular event (e.g. myocardial infarction). Cardiovascular disease (CVD) and COPD share various risk factors including hypertension, sedentarism, smoking and poor diet but the underlying mechanisms have not been fully established. However, there is emerging and compelling experimental and clinical evidence to show that increased oxidative stress causes pulmonary inflammation and that the spill over of pro-inflammatory mediators from the lungs into the systemic circulation drives a persistent systemic inflammatory response that alters blood vessel structure, through vascular remodelling and arterial stiffness resulting in atherosclerosis. In addition, regulation of endothelial-derived vasoactive substances (e.g. nitric oxide (NO)), which control blood vessel tone are altered by oxidative damage of vascular endothelial cells, thus promoting vascular dysfunction, a key driver of CVD. In this review, the detrimental role of oxidative stress in COPD and comorbid CVD are discussed and we propose that targeting oxidant-dependent mechanisms represents a novel strategy in the treatment of COPD-associated CVD.