Association of sleep apnea and sleep duration with peripheral artery disease: The Multi-Ethnic Study of Atherosclerosis (MESA)

Hypoxia-Induced Insulin Resistance Mediates the Elevated Cardiovascular Risk in Patients with Obstructive Sleep Apnea: A Comprehensive Review

Patients with obstructive sleep apnea (OSA) experience insulin resistance and its clinical consequences, including hypertriglyceridemia, reduced high density lipoprotein-associated cholesterol (HDL-c), visceral adiposity, hepatic steatosis, increased epicardial fat thickness, essential hypertension, glucose intolerance, increased risk for type 2 diabetes, chronic kidney disease, subclinical vascular damage, and increased risk for cardiovascular events. Obesity is a major contributor to OSA. The prevalence of OSA is almost universal among patients with severe obesity undergoing bariatric surgery. However, insulin resistance and its clinical complications occur in OSA patients irrespective of general obesity (body mass index). In OSA patients, apnea episodes during sleep induce oxyhemoglobin desaturation and tissue hypoxia. Insulin resistance is an adaptive response to tissue hypoxia and develops in conditions with limited tissue oxygen supply, including healthy subjects exposed to hypobaric hypoxia (high altitude) and OSA patients. Indicators of oxyhemoglobin desaturation have been robustly and independently linked to insulin resistance and its clinical manifestations in patients with OSA. Insulin resistance mediates the elevated rate of type 2 diabetes, chronic kidney disease, and cardiovascular disease unexplained with traditional cardiovascular risk factors present in OSA patients. Pathophysiological processes underlying hypoxia-induced insulin resistance involve hypoxia inducible factor-1 upregulation and peroxisome proliferator-activated receptor-gamma (PPAR- γ ) downregulation. In human adipose tissue, PPAR- γ activity promotes glucose transport into adipocytes, lipid droplet biogenesis, and whole-body insulin sensitivity. Silencing of PPAR- γ in the adipose tissue reduces glucose uptake and fat accumulation into adipocytes and promotes insulin resistance. In conclusion, tissue hypoxia drives insulin resistance and its clinical consequences in patients with OSA, regardless of body mass index.

Modifiable Lifestyle Factors, Genetic Risk, and Incident Peripheral Artery Disease Among Individuals With Type 2 Diabetes: A Prospective Study

OBJECTIVE

To prospectively evaluate the association between modifiable lifestyle factors and peripheral artery disease (PAD) among individuals with type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

We included 14,543 individuals with T2D from the UK Biobank. We defined a weighted healthy lifestyle score using nonsmoking, regular physical activity, high-quality diet, moderate alcohol consumption, optimal waist-to-hip ratio, and adequate sleep duration, and categorized into unfavorable, intermediate, and favorable lifestyles. We created a genetic risk score (GRS) using 19 single nucleotide polymorphisms previously found to be associated with PAD. We modeled the association between lifestyle score and PAD, overall and stratified by PAD genetic susceptibility.

RESULTS

After a median 13.5 years of follow-up, 628 incident cases of PAD were documented. A linear inverse association between the weighted lifestyle score and PAD was observed, with a hazard ratio (HR) (95% CI) of 0.27 (0.19, 0.38) for favorable compared with unfavorable lifestyle (Ptrend < 0.0001). An estimated 58.3% (45.0%, 69.1%) of PAD in this population could be potentially avoidable if all participants attained a favorable lifestyle. Moreover, the PAD GRS was associated with increased PAD risk (HR [95% CI] per SD increment: 1.13 [1.03, 1.23]). A favorable lifestyle was able to partially mitigate the excess risk of PAD associated with higher GRS, albeit as a nonsignificant interaction. Several biomarkers in the lipid metabolism, hepatic/renal function, and systemic inflammation pathways collectively explained 13.3% (8.5%, 20.1%) of the association between weighted lifestyle score and PAD.

CONCLUSIONS

A favorable lifestyle was associated with lower risk of PAD among individuals with T2D, independent of genetic predisposition to PAD.

Circadian Disruption and the Molecular Clock in Atherosclerosis and Hypertension

Circadian rhythms are crucial for maintaining vascular function and disruption of these rhythms are associated with negative health outcomes including cardiovascular disease and hypertension. Circadian rhythms are regulated by the central clock within the suprachiasmatic nucleus of the hypothalamus and peripheral clocks located in nearly every cell type in the body, including cells within the heart and vasculature. In this review, we summarize the most recent preclinical and clinical research linking circadian disruption, with a focus on molecular circadian clock mechanisms, in atherosclerosis and hypertension. Furthermore, we provide insight into potential future chronotherapeutics for hypertension and vascular disease. A better understanding of the influence of daily rhythms in behaviour, such as sleep/wake cycles, feeding, and physical activity, as well as the endogenous circadian system on cardiovascular risk will help pave the way for targeted approaches in atherosclerosis and hypertension treatment/prevention.

Sleep duration, daytime napping, and risk of peripheral artery disease: multinational cohort and Mendelian randomization studies

Aims

Sleep duration has been associated with cardiovascular disease, however the effect of sleep on peripheral artery disease (PAD) specifically remains unestablished. We conducted observational and Mendelian randomization (MR) analyses to assess the associations of sleep duration and daytime napping with PAD risk.

Methods and results

Sleep traits were assessed for associations with incident PAD using cohort analysis among 53 416 Swedish adults. Replicated was sought in a case-control study of 28 123 PAD cases and 128 459 controls from the veterans affairs Million Veteran Program (MVP) and a cohort study of 452 028 individuals from the UK Biobank study (UKB). Two-sample Mendelian randomization (MR) was used for casual inference-based analyses of sleep-related traits and PAD (31 307 PAD cases 211 753 controls). Observational analyses demonstrated a U-shaped association between sleep duration and PAD risk. In Swedish adults, incident PAD risk was higher in those with short sleep [<5 h; hazard ratio (HR) 1.74; 95% confidence interval (CI) 1.31-2.31] or long sleep (≥8 h; HR 1.24; 95% CI 1.08-1.43), compared to individuals with a sleep duration of 7 to <8 h/night. This finding was supported by the analyses in MVP and UKB. Observational analysis also revealed positive associations between daytime napping (HR 1.32, 95% CI 1.18-1.49) with PAD. MR analysis supported an inverse association between sleep duration [odds ratio (OR) per hour increase: 0.79, 95% CI, 0.55, 0.89] and PAD and an association between short sleep and increased PAD (OR 1.20, 95% CI, 1.04-1.38).

Conclusion

Short sleep duration was associated with an increased risk of PAD.

Relationship Between Peripheral Arterial Diseases and Obstructive Sleep Apnea: A Systematic Review

Although the effects of obstructive sleep apnea (OSA) on the cardiovascular outcomes of coronary artery disease (CAD) have been well-established, its significance on the occurrence of peripheral arterial disease (PAD) remains debatable. Prompt diagnosis and treatment of OSA would help reduce cardiovascular comorbidities. Our study aimed to assess the relationship between OSA and PAD and report any statistical association between the two conditions. Here, we investigated the prevalence and association of OSA in PAD based on related articles from PubMed, Embase, and the Cochrane Library. All databases were systematically searched from January 2000 to December 2020. A total of 238 articles deemed relevant were assessed for eligibility, of which seven articles were selected for the systematic review. Seven prospective cohorts were qualified for inclusion, which included 26,881 male and 34,403 female patients (N = 61,284). The retrieved articles described OSA severity based on the apnea-hypopnea index and reported increased OSA prevalence in PAD patients. The Epworth sleepiness scale showed no association between OSA severity, poor ankle-brachial index values, and increased daytime sleepiness. The prevalence of OSA increased in patients with PAD. Further research and prospective clinical trials are required to establish strong associations between OSA and PAD to make appropriate changes in patient management algorithms and improve their outcomes.

Sleep Irregularity and Subclinical Markers of Cardiovascular Disease: The Multi-Ethnic Study of Atherosclerosis

Background Sleep irregularity has been linked to incident cardiovascular disease. Less is known about associations of sleep regularity with atherosclerosis. We examined cross-sectional associations of actigraphy-assessed sleep duration and sleep timing regularity with subclinical atherosclerosis in the community-based MESA (Multi-Ethnic Study of Atherosclerosis). Methods and Results MESA Sleep Ancillary Study participants (N=2032; mean age, 68.6±9.2 years; 37.9% White) completed 7-day wrist actigraphy. Participants underwent assessments of coronary artery calcium, carotid plaque presence, carotid intima-media thickness, and the ankle-brachial index. Sleep regularity was quantified by the 7-day with-in person SD of sleep duration and sleep onset timing. Relative risk regression models were used to calculate prevalence ratios and 95% CIs. Models are adjusted for demographics, cardiovascular disease risk factors, and other objectively assessed sleep characteristics including obstructive sleep apnea, sleep duration, and sleep fragmentation. After adjustment, compared with participants with more regular sleep durations (SD ≤60 minutes), participants with greater sleep duration irregularity (SD >120 minutes) were more likely to have high coronary artery calcium burden (>300; prevalence ratio, 1.33 [95% CI, 1.03-1.71]) and abnormal ankle-brachial index (<0.9; prevalence ratio, 1.75 [95% CI, 1.03-2.95]). Compared with participants with more regular sleep timing (SD ≤30 minutes), participants with irregular sleep timing (SD >90 minutes) were more likely to have high coronary artery calcium burden (prevalence ratio, 1.39 [95% CI, 1.07-1.82]). Associations persisted after adjustment for cardiovascular disease risk factors and average sleep duration, obstructive sleep apnea, and sleep fragmentation. Conclusions Sleep irregularity, particularly sleep duration irregularity, was associated with several measures of subclinical atherosclerosis. Sleep regularity may be a modifiable target for reducing atherosclerosis risk. Future investigation into cardiovascular risk reduction interventions targeting sleep irregularity may be warranted.

Sleep Duration and Risks of Incident Cardiovascular Disease and Mortality Among People With Type 2 Diabetes

OBJECTIVE

People with type 2 diabetes may have insufficient or prolonged sleep that could accelerate cardiovascular disease (CVD) onset, but existing evidence from prospective studies has been limited. We examined the association of sleep duration with CVD incidence and mortality in this high-risk population.

RESEARCH DESIGN AND METHODS

This prospective study included 18,876 participants with type 2 diabetes in the UK Biobank who were free of CVD and cancer at baseline. Habitual sleep duration was obtained using a baseline questionnaire. Cox proportional hazards regression models were used to examine the association between sleep duration and CVD events.

RESULTS

During an average follow-up of 11.0-12.0 years, we documented 2,570 incident cases of atherosclerotic cardiovascular disease (ASCVD) and 598 CVD deaths. Compared with sleeping for 7 h/day, the multivariable-adjusted hazard ratios of ≤5 and ≥10 h/day were 1.26 (95% CI 1.08, 1.48) and 1.41 (1.16, 1.70) for incident ASCVD, 1.22 (0.99, 1.50) and 1.16 (0.88, 1.52) for coronary artery disease, 1.70 (1.23, 2.35) and 2.08 (1.44, 3.01) for ischemic stroke, 1.02 (0.72, 1.44) and 1.45 (1.01, 2.10) for peripheral artery disease, and 1.42 (1.02, 1.97) and 1.85 (1.30, 2.64) for CVD mortality. Similar results were observed in most sensitivity analyses that aimed to address potential reverse causation and in the joint analyses of sleep duration and metabolic control or diabetes severity status.

CONCLUSIONS

Short and long sleep durations were independently associated with increased risks of CVD onset and death among people with type 2 diabetes.

Redefining Cardiovascular Health to Include Sleep: Prospective Associations With Cardiovascular Disease in the MESA Sleep Study

Background Although sufficient and healthy sleep is inversely associated with cardiovascular disease (CVD) and its risk factors, the American Heart Association's Life's Simple 7 (LS7), as a measure of cardiovascular health (CVH), did not include sleep. We evaluated an expanded measure of CVH that includes sleep as an eighth metric in relation to CVD risk. Methods and Results The analytic sample consisted of MESA (Multi-Ethnic Study of Atherosclerosis) Sleep Study participants who had complete data on sleep characteristics from overnight polysomnography, 7-day wrist actigraphy, validated questionnaires, and the outcome. We computed the LS7 score and 4 iterations of a new CVH score: score 1 included sleep duration, score 2 included sleep characteristics linked to CVD in the literature (sleep duration, insomnia, daytime sleepiness, and obstructive sleep apnea), scores 3 and 4 included sleep characteristics associated with CVD in MESA (score 3: sleep duration and efficiency, daytime sleepiness, and obstructive sleep apnea; score 4: score 3+sleep regularity). Multivariable-adjusted logistic and Cox proportional hazards models evaluated associations of the LS7 and CVH scores 1 to 4 with CVD prevalence and incidence. Among 1920 participants (mean age: 69±9 years; 54% female), there were 95 prevalent CVD events and 93 incident cases (mean follow-up, 4.4 years). Those in the highest versus lowest tertile of the LS7 score and CVH scores 1 to 4 had up to 80% lower odds of prevalent CVD. The LS7 score was not significantly associated with CVD incidence (hazard ratio, 0.62 [95% CI, 0.37-1.04]). Those in the highest versus lowest tertile of CVH score 1, which included sleep duration, and CVH score 4, which included multidimensional sleep health, had 43% and 47% lower incident CVD risk (hazard ratio, 0.57 [95% CI, 0.33-0.97]; and hazard ratio, 0.53 [95% CI, 0.32-0.89]), respectively. Conclusions CVH scores that include sleep health predicted CVD risk in older US adults. The incorporation of sleep as a CVH metric, akin to other health behaviors, may enhance CVD primordial and primary prevention efforts. Findings warrant confirmation in larger cohorts over longer follow-up.

Causal Association of Cardiovascular Risk Factors and Lifestyle Behaviors With Peripheral Artery Disease: A Mendelian Randomization Approach

Background

We investigated the causal associations between the genetic liability to cardiovascular and lifestyle risk factors and peripheral artery disease (PAD), using a Mendelian randomization approach.

Methods and Results

We performed a 2‐sample inverse‐variance weighted Mendelian randomization analysis, multiple sensitivity analyses to assess pleiotropy and multivariate Mendelian randomization analyses to assess mediating/confounding factors. European‐ancestry genomic summary data (P<5×10⁻⁸) for type 2 diabetes, lipid‐fractions, smoking, alcohol and coffee consumption, physical activity, sleep, and education level were selected. Genetic associations with PAD were extracted from the Million‐Veteran‐Program genome‐wide association studies (cases=31 307, controls=211 753, 72% European‐ancestry) and the GoLEAD‐SUMMIT genome‐wide association studies (11 independent genome‐wide association studies, European‐ancestry, cases=12 086, controls=449 548). Associations were categorized as robust (Bonferroni‐significant (P<0.00294), consistent over PAD‐cohorts/sensitivity analyses), suggestive (P value: 0.00294–0.05, associations in 1 PAD‐cohort/inconsistent sensitivity analyses) or not present. Robust evidence for genetic liability to type 2 diabetes, smoking, insomnia, and inverse associations for higher education level with PAD were found. Suggestive evidence for the genetic liability to higher low‐density lipoprotein cholesterol, triglyceride‐levels, alcohol consumption, and inverse associations for high‐density lipoprotein cholesterol, and increased sleep duration were found. No associations were found for physical activity and coffee consumption. However, effects fully attenuated for low‐density lipoprotein cholesterol and triglycerides after correcting for apoB, and for insomnia after correcting for body mass index and lipid‐fractions. Nonsignificant attenuation by potential mediators was observed for education level and type 2 diabetes.

Conclusions

Detrimental effects of smoking and type 2 diabetes, but not of low‐density lipoprotein cholesterol and triglycerides, on PAD were confirmed. Lower education level and insomnia were identified as novel risk factors for PAD; however, complete mediation for insomnia and incomplete mediation for education level by downstream risk factors was observed.

Swedish snuff (snus) dipping, cigarette smoking, and risk of peripheral artery disease: a prospective cohort study

Tobacco smoking is an important risk factor for peripheral artery disease (PAD), but it remains unknown whether smokeless tobacco, such as Swedish snuff (snus), is also associated with this disease. We used data from the Cohort of Swedish Men including 24,085 men. Individuals were grouped into never, past, and current snus dippers as well as never, past quitting ≥ 10 years, past, quitting < 10 years, and current smokers. Incident PAD cases were defined by linkage of the cohort with the Swedish National Patient Register. Cox proportional hazards regression was used to analyze the data. Over a mean follow-up period of 9.1 years (from July 1, 2009 to December 31, 2019), 655 incident PAD cases were ascertained. Cigarette smoking but not Swedish snus dipping was associated with an increased risk of PAD. Compared with never snus dippers, the hazard ratio of PAD was 0.95 (95% confidence interval [CI] 0.73–1.24) for past snus dippers and 0.88 (95% CI 0.66–1.17) for current snus dippers. Compared to never smokers, the hazard ratio of PAD was 1.38 (95% CI 1.14–1.68) for past smoker who stopped smoking for ≥ 10 years, 2.61 (95% CI 1.89–3.61) for past smoker who stopped smoking for < 10 years, and 4.01 (95% CI 3.17, 5.08) for current smoker. In conclusion, cigarette smoking but not Swedish snus dipping increases the risk of PAD.

Moderate to severe obstructive sleep apnea is independently associated with inter-arm systolic blood pressure difference: Tokyo Sleep Heart Study

OBJECTIVE

Obstructive sleep apnea (OSA) is recognized as an independent risk factor for cardiovascular disease. On the other hand, inter-arm systolic blood pressure difference (IAD), inter-ankle systolic blood pressure difference (IAND), and ankle-brachial index (ABI) are all known predictors of cardiovascular events. The aim of the present study was to investigate the association between OSA and four-limb blood pressure differences.

METHODS

We conducted this cross-sectional study in a large sleep cohort from Tokyo Sleep Heart Study. In 2643 consecutive patients who visited our sleep clinic for polysomnography between 2005 and 2017, all the patients underwent blood pressure measurement simultaneously in all the four limbs by oscillometric methods.

RESULTS

The prevalence rate of IAD ≥10 mmHg was significantly higher in the moderate OSA (15 ≤ apnea-hypopnea index [AHI] < 30) group (4.2%) and severe OSA (AHI ≥ 30) group (4.6%) than that in the no/mild (AHI < 15) OSA group (1.4%). Multivariate logistic regression analysis also identified moderate to severe OSA as being significantly associated with IAD ≥10 mmHg, even after adjustments for confounding variables (moderate OSA: odds ratio [OR], 4.869; 95% confidence interval [CI], 1.080-21.956; P = 0.039; severe OSA: OR, 5.301; 95% CI, 1.226-22.924; P = 0.026). However, there were no significant associations of the OSA severity with IAND ≥15 mmHg or ABI <0.9.

CONCLUSIONS

Moderate to severe OSA was independently associated with the IAD, not but with the IAND or ABI.

The Interaction Between Self-Reported Sleep Duration and Physical Activity on Peripheral Artery Disease in Chinese Adults: A Cross-Sectional Analysis in the Tianning Cohort Study

Purpose

Sleep duration was associated with large artery atherosclerosis, but its association with atherosclerosis in lower extremity arteries was not well studied. Together with sleep, physical activity constitutes main component of our daily life and influences sleep. Here, we aimed to examine the independent and joint associations of sleep duration and physical activity with peripheral artery disease (PAD) in Chinese adults.

Patients and Methods

In Tianning cohort, night-time sleep duration and physical activity were assessed by the Pittsburgh Sleep Quality Index and the Global Physical Activity Questionnaire, respectively, for 5130 participants (51.0±15.6 years, 58.7% female). PAD was defined as ankle-brachial index (ABI) <0.9. General linear, and logistic regression models were used to assess the associations of sleep duration and physical activity with PAD. The biological interaction between sleep duration and physical activity on PAD was examined using additive model.

Results

Compared to participants sleeping 6-8.9 h, those sleeping ≥9 h had a 0.02 lower ABI (β=-0.02, P=0.007) and 38% higher odds of PAD (OR=1.38, P=0.035). Compared to physically active participants sleeping 6-8.9 h, among ≥9 h group, physically inactive individuals had significantly increased odds of PAD (OR=2.40, P<0.001), whereas physically active individuals did not (OR=1.15, P=0.472). On additive scale, attributable proportion due to interaction (0.40, 95% CI: 0.07, 0.73) indicated a significant interaction between sleep duration and physical activity on PAD.

Conclusion

Being physically active may attenuate the detrimental association between prolonged sleep duration and PAD. Moreover, we found a significant interaction between prolonged sleep duration and physical inactivity in the prevalence of PAD.

Cardiovascular Disease in Patients with Chronic Obstructive Pulmonary Disease, Obstructive Sleep Apnoea Syndrome and Overlap Syndrome

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnoea syndrome (OSAS) are among the most prevalent chronic respiratory disorders. Accumulating data suggest that there is a significant burden of cardiovascular disease (CVD) in patients with COPD and OSAS, affecting negatively patients' quality of life and survival. Overlap syndrome (OS), i.e. the co-existence of both COPD and OSAS in the same patient, has an additional impact on the cardiovascular system multiplying the risk of morbidity and mortality. The underlying mechanisms for the development of CVD in patients with either OSAS or COPD and OS are not entirely elucidated. Several mechanisms, in addition to smoking and obesity, may be implicated, including systemic inflammation, increased sympathetic activity, oxidative stress and endothelial dysfunction. Early diagnosis and proper management of these patients might reduce cardiovascular risk and improve patients' survival. In this review, we summarize the current knowledge regarding epidemiological aspects, pathophysiological mechanisms and present point-to-point specific associations between COPD, OSAS, OS and components of CVD, namely, pulmonary hypertension, coronary artery disease, peripheral arterial disease and stroke.

Sleep duration and vascular inflammation using hybrid positron emission tomography/magnetic resonance imaging: results from the Multi-Ethnic Study of Atherosclerosis (MESA)

STUDY OBJECTIVES

Short sleep duration (SD) is associated with cardiovascular disease (CVD). We investigated the relationship between objective SD and subclinical atherosclerosis employing hybrid PET/MRI with ¹⁸F-FDG tracer in the MESA cohort.

METHODS

We utilized data from MESA-SLEEP and MESA-PET ancillary studies. SD and sleep fragmentation index (SFI) were assessed using 7-day actigraphy. The primary and secondary outcomes were carotid inflammation, defined using target-to-background ratios (TBR), and measures of carotid wall remodeling (carotid wall thickness [CWT]), summarized by SD category. Multivariate linear regression was performed to assess the association between SD and SFI with the primary/secondary outcomes, adjusting for several covariates including apnea-hypopnea index (AHI), and CVD risk.

RESULTS

Our analytical sample (n=58) was 62% female (mean age 68±8.4 years). Average SD was 5.1±0.9 hours in the short SD group (≤6 hours/night, 31%), and 7.1±0.8 hours in the normal SD group (69%). Prevalence of pathologic vascular inflammation (TBRmax>1.6) was higher in the short SD group (89% vs. 53%, p=0.009). Those with short SD had a higher TBRmax (1.77 vs 1.71), though this was not statistically significant (p=0.39). CWT was positively correlated with SFI even after adjusting for covariates (Beta [SE]=0.073±[0.032], p=0.025).

CONCLUSIONS

Prevalence of pathologic vascular inflammation was higher among those who slept ≤6 hours, and vascular inflammation was higher among those with a SD of ≤6 hours. Interestingly, SFI was positively correlated with CWT even after adjustment for covariates. Our results are hypothesis-generating but suggest that both habitual SD and SFI should be investigated in future studies as potential risk factors for subclinical atherosclerosis.

An Update on Obstructive Sleep Apnea for Atherosclerosis: Mechanism, Diagnosis, and Treatment

The occurrence and development of atherosclerosis could be influenced by intermittent hypoxia. Obstructive sleep apnea (OSA), characterized by intermittent hypoxia, is world-wide prevalence with increasing morbidity and mortality rates. Researches remain focused on the study of its mechanism and improvement of diagnosis and treatment. However, the underlying mechanism is complex, and the best practice for OSA diagnosis and treatment considering atherosclerosis and related cardiovascular diseases is still debatable. In this review, we provided an update on research in OSA in the last 5 years with regard to atherosclerosis. The processes of inflammation, oxidative stress, autonomic nervous system activation, vascular dysfunction, platelet activation, metabolite dysfunction, small molecule RNA regulation, and the cardioprotective occurrence was discussed. Additionally, improved diagnosis such as, the utilized of portable device, and treatment especially with inconsistent results in continuous positive airway pressure and mandibular advancement devices were illustrated in detail. Therefore, further fundamental and clinical research should be carried out for a better understanding the deep interaction between OSA and atherosclerosis, as well as the suggestion of newer diagnostic and treatment options.

Effects of sleep apnea hypopnea syndromes on cardiovascular events: a systematic review and meta-analysis

PURPOSE

Previous studies suggest that sleep apnea hypopnea syndrome (SAHS) is an independent risk factor that contributes to certain cardiovascular events. However, there are studies arguing that patients with SAHS had lower peak troponin levels when suffering cardiovascular events compared to patients without SAHS, which indicates that there may potentially be a protective effect of SAHS. This meta-analysis aimed to assess the impact of SAHS on cardiovascular events.

METHODS

Databases were searched for studies that examined cardiac biomarkers or reported angiographic data when patients with SAHS experienced cardiovascular events. The data about peak cardiac biomarkers and angiographic coronary lesion were extracted and then used to compute the pooled standardized mean difference (SMD) and 95% confidence interval (95% CI).

RESULTS

Among 26 studies included in the meta-analysis, there was not a definite difference between the SAHS group and the control group for troponins (SMD, 0.05; 95% CI, [- 0.16, 0.26]), creatine kinase (SMD, - 0.08; 95% CI, [- 0.38, 0.22]), and CK-MB (SMD, - 0.11; 95% CI, [- 0.51, 0.29]). However, patients with SAHS revealed worse coronary lesion condition grading via both Gensini score (SMD, 0.63; 95% CI, [0.31, 0.95]) and SYNTAX score (SMD, 0.99; 95% CI, [0.31-1.67]).

CONCLUSIONS

Ischemic preconditioning induced by the intermittent hypoxia at the early stage could generate a cardiac protection effect, which would then benefit SAHS patients encountering a major adverse cardiovascular event.

Activating transcription factor 3 is a potential target and a new biomarker for the prognosis of atherosclerosis

ATF3 (activating transcription factor 3) is a member of the mammalian activation transcription factor/cAMP-responsive element-binding (CREB) family. It plays a role in inflammation and innate immunity, and suggests that ATF3 is associated with atherosclerosis. In our study, we analyzed datasets of atherosclerosis from the NCBI-GEO (Gene Expression Omnibus) database and found that expression levels of ATF3 were lower in macrophages from ruptured atherosclerotic plaques than from stable atherosclerotic plaques. Expression levels of ATF3 correlated with the stability of atherosclerotic plaques. KEGG analysis of different expression genes (DEGs) between ruptured and stable atherosclerotic plaques was performed by Metascape database. The PI3K-AKT pathway may be a potential pathway of the formation of ruptured atherosclerotic plaques. High-fat diet-induced atherosclerosis apoE-/- mice were divided into two groups: a model group and an ATF3 overexpression (OE)-group. Tests on atherosclerotic plaques in the aortic root suggested that absence of ATF3 and increase of macrophages may be risk factors for the formation of ruptured atherosclerotic plaques. We found decreased areas of lesions in aortic roots and branches of aortic arch, as well as increased lesional content of macrophages as well as TUNEL-positive areas. Consistent with these results, we found reduced degradation and incidence of elastic plate cracks accompanied by suppressed MMPs expression and transduction pathway protein PI3K/AKT activation. These data suggest that ATF3 is a signaling molecule that mediates the progression and stability of atherosclerotic plaques. ATF3 could be a potential new biomarker for the prognosis of atherosclerosis and may be a therapeutic target to reduce atherosclerosis.

Accelerometer-Measured Sleep Duration and Clinical Cardiovascular Risk Factor Scores in Older Women

BACKGROUND

Evidence suggests that short and long sleep durations are potential lifestyle factors associated with cardiovascular disease (CVD). Research on sleep duration and CVD risk is limited by use of self-report sleep measures, homogeneous populations, and studies on individual CVD risk factors. For women, risk of CVD and inadequate sleep duration increases with age. We hypothesized that accelerometer-measured sleep duration was associated with 10-year predicted probability of future CVD risk in a cohort of aging women.

METHODS

This cross-sectional analysis included 3,367 older women (mean age 78.9 years; 53.3% White), from the Objective Physical Activity and Cardiovascular Health Study, ancillary study to the Women's Health Initiative. Women wore ActiGraph GT3X+ accelerometers on the hip for 24 hours/7 days. A 10-year predicted probability of future CVD risk, the Reynolds Risk Score (RRS), was computed using age, systolic blood pressure, high-sensitivity C-reactive protein (CRP), total and HDL cholesterol, diabetes mellitus status, smoking status, and family history of CVD. Average nightly sleep duration was derived from accelerometer data. Adjusted linear regression models investigated the association between sleep duration and RRS.

RESULTS

Results suggested a U-shaped relationship between sleep duration and RRS, with both short and long sleep associated with higher RRS (p < .001). The association remained significant after adjustments for race/ethnicity, education, lifestyle factors, and health status indicators.

CONCLUSION

In older women, actigraphy-ascertained sleep duration was associated with a 10-year predicted probability of future CVD risk. This study supports sleep duration as a modifiable risk factor for CVD in older women.

Obstructive sleep apnea and peripheral vascular disease: a systematic review based on current literature

Introduction

Obstructive sleep apnea (OSA) is an established risk factor for poor cardiovascular outcomes and coronary artery disease, but its influence on the development of peripheral artery disease (PAD) is not well established. The aim of our study was to understand the mutual prevalence of OSA and PAD and any reported statistical association between the two conditions.

Methods

PubMed, Ovid Embase, Web of Science, Cochrane library and clinicaltrials.gov databases were systematically searched up to 29 November 2018. A total of 844 articles were identified and 744 articles were screened for relevance.

Results and Conclusion

Eleven prospective cohorts qualified for inclusion with N = 63,642 (M = 28,062, F = 35,494). All studies evaluated OSA severity primarily with apnea–hypopnea index (AHI) values. The overall prevalence of PAD was 20.5% (N = 13,068). Except for two studies, all studies reported an increased prevalence of OSA in patients with PAD. OSA severity was not found to have an association with poor ankle brachial index values or increasing daytime sleepiness as measured by Epworth sleepiness scale. Further prospective clinical trials are required to further delineate this finding.

Broken sleep predicts hardened blood vessels

Why does poor-quality sleep lead to atherosclerosis? In a diverse sample of over 1,600 individuals, we describe a pathway wherein sleep fragmentation raises inflammatory-related white blood cell counts (neutrophils and monocytes), thereby increasing atherosclerosis severity, even when other common risk factors have been accounted for. Improving sleep quality may thus represent one preventive strategy for lowering inflammatory status and thus atherosclerosis risk, reinforcing public health policies focused on sleep health.

Why does poor quality sleep correlate with cardiovascular disease? A large population-based study suggests that fragmented sleep contributes to atherosclerosis in humans by increasing inflammatory-related activity of white blood cells.

Lipoprotein-associated phospholipase A2 predicted cardiovascular disease in obstructive sleep apnea syndrome

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for cardiovascular disease (CVD). As a new inflammatory biomarker of CVD, rare attention has been paid to the roles of lipoprotein-associated phospholipase (Lp-PLA2) in OSAS studies. In this study, we aimed to investigate the correlation between Lp-PLA2 and concomitant CVD in OSAS patients.

METHODS

In this prospective study, 152 OSAS patients were further divided into mild, moderate, and severe OSAS subgroups. They presented heart failure, coronary artery disease, or arrhythmia were confirmed with CVD. Thirty-one subjects without OSAS were recruited for the control group. The relationship between Lp-PLA2 and concomitant CVD in OSAS patients was analyzed.

RESULTS

Serum Lp-PLA2 values were significantly higher in the severe and moderate OSAS group compared with mild OSAS and OSAS negative groups (P = 0.025). Significant increase was noticed in serum Lp-PLA2 levels in CVD patients compared with those without in severe-moderate-mild OSAS (P < 0.05). In logistic regression analysis, the level of Lp-PLA2 was proved as a significant independent predictor for CVD (OR = 1.117, P = 0.008). The ROC analysis indicated that the best cut-off value of Lp-PLA2 for predicting CVD in OSAS patients was 238.09 ng/ml. The positive and negative predictive values were 72.5% and 70.5%, respectively. The sensitivity was 46.8% and the specificity was 87.8%.

CONCLUSIONS

Lp-PLA2 might be associated with the severity of OSAS and the occurrence of CVD in OSAS patients. Lp-PLA2 is expected to be a promising biomarker candidate in predicting CVD in patients with OSAS due to test convenience.

Bidirectional relationship between sleep and Alzheimer's disease: role of amyloid, tau, and other factors

As we age, we experience changes in our nighttime sleep and daytime wakefulness. Individuals afflicted with Alzheimer's disease (AD) can develop sleep problems even before memory and other cognitive deficits are reported. As the disease progresses and cognitive changes ensue, sleep disturbances become even more debilitating. Thus, it is imperative to gain a better understanding of the relationship between sleep and AD pathogenesis. We postulate a bidirectional relationship between sleep and the neuropathological hallmarks of AD; in particular, the accumulation of amyloid-β (Aβ) and tau. Our research group has shown that extracellular levels of both Aβ and tau fluctuate during the normal sleep-wake cycle. Disturbed sleep and increased wakefulness acutely lead to increased Aβ production and decreased Aβ clearance, whereas Aβ aggregation and deposition is enhanced by chronic increased wakefulness in animal models. Once Aβ accumulates, there is evidence in both mice and humans that this results in disturbed sleep. New findings from our group reveal that acute sleep deprivation increases levels of tau in mouse brain interstitial fluid (ISF) and human cerebrospinal fluid (CSF) and chronic sleep deprivation accelerates the spread of tau protein aggregates in neural networks. Finally, recent evidence also suggests that accumulation of tau aggregates in the brain correlates with decreased nonrapid eye movement (NREM) sleep slow wave activity. In this review, we first provide a brief overview of the AD and sleep literature and then highlight recent advances in the understanding of the relationship between sleep and AD pathogenesis. Importantly, the effects of the bidirectional relationship between the sleep-wake cycle and tau have not been previously discussed in other reviews on this topic. Lastly, we provide possible directions for future studies on the role of sleep in AD.

Sleep-Disordered Breathing and Peripheral Arterial Disease: Current Evidence

INTRODUCTION

Sleep-disordered breathing (SDB) is associated with atherosclerosis. Peripheral arterial disease (PAD) is a manifestation of atherosclerosis in lower extremity arteries. No systematic review addressing the relationship between PAD and SDB was found. We performed this study aimed to summarize the relationship between SDB and PAD described in current clinical studies.

MATERIAL AND METHODS

PubMed and Embase electronic databases were searched for clinical articles (published before 3 April, 2019) describing studies that evaluated the association between SDB and PAD. We showed the results involved in the association in clinical studies.

RESULTS

In total, 8 clinical studies have been included, and most of them were cross-sectional studies. Six articles demonstrated the coexistence of SDB and PAD, evidenced by high prevalence of SDB in patients with PAD and vice versa. Meanwhile, the included studies exhibited independent positive associations between SDB or sleep parameters and PAD after adjusting for multiple confounders.

CONCLUSION

From present clinical prospective, positive association between SDB and PAD was shown. More prospective, randomized controlled studies are needed to establish the cause-effect relationships involved.

Sleep, Autonomic Nervous Function and Atherosclerosis

Behavioral and psychosocial factors related to development of cardiovascular disease have been gaining increased attention. Notably, sleep is considered to be one of the most important behavioral factors involved in progression of atherosclerosis and cardiovascular events, with autonomic nervous function a potential mechanism. Several studies have shown associations of sleep and autonomic dysfunction with major surrogate markers of atherosclerosis, such as carotid intima-media thickness and arterial stiffness. Endocrinological, immunological, oxidative, inflammatory, and metabolic responses, as well as endothelial dysfunction may mediate the effects of the autonomic nervous system. For this review, we examined recent findings related to sleep, autonomic nervous dysfunction, and atherosclerosis, with the aim of understanding the involved pathophysiological mechanisms.

CHADS₂, CHA₂DS₂ASc, and New ABCD Scores Predict the Risk of Peripheral Arterial Disease in Patients with Sleep Apnea

The association between sleep apnea (SA) and peripheral artery disease (PAD) remains debatable, and there is no clinical tool to predict incident PAD in SA patients. The CHADS₂ score has been found useful in predicting PAD risk. This study was designed to investigate the association between these diseases and the usefulness of CHADS₂ and CHA₂DS₂ASc scores in predicting subsequent PAD in SA patients. From a population-based database of one-million representative subjects, adult patients with SA diagnosis were enrolled as the suspected SA group, and those having SA diagnosis after polysomnography were further extracted as the probable SA group. Twenty sex- and age-matched control subjects were randomly selected for each SA patients. The occurrence of PAD after SA was taken as the primary endpoint. Totally, 10,702 and 4242 patients were enrolled in the suspected and probable SA groups, respectively. The cumulative incidence of PAD was similar between SA patients and the corresponding control groups. Multivariable Cox regression analyses showed that SA was not an independent risk factor for subsequent PAD. Sensitivity analyses using propensity score-matched cohorts showed consistent results. Furthermore, in stratifying the SA patients by CHADS₂, CHA₂DS₂ASc, or a newly-proposed ABCD (composed of Age, high Blood pressure, Cerebral vascular disease, and Diabetes mellitus) score, patients with higher scores predicted higher risks of subsequent PAD, while the ABCD score appeared to be the most robust. Aggressive risk modification is suggested to reduce the subsequent PAD risk in SA patients with a higher CHADS₂, CHA₂DS₂ASc, or ABCD score.

Association of sleep-disordered breathing with severe chronic vascular disease in patients with type 2 diabetes

BACKGROUND

Severe chronic vascular disease (CVD) is a major cause of co-morbidity and mortality in patients with type 2 diabetes (DM2). Sleep-disordered breathing (SDB) has been linked to CVD in the general population due to enhanced sympathetic activation, oxidative stress, endothelial dysfunction, and hypertension; however data for DM2 patients is scarce. Therefore, the aim of the present analysis to assess whether SDB is associated with CVD in patients with DM2, independent of other known associated factors.

METHODS

We analyzed cross-sectional data of 679 patients with DM2 from the DIACORE-SDB sub-study for association of SDB with CVD. SDB was assessed with a validated 2-channel ambulatory monitoring device. CVD was ascertained as a previous diagnosis of peripheral artery disease (PAD), coronary artery disease (CAD), or stroke via medical records and general practitioners.

RESULTS

Of the analyzed 679 patients, 228 (34%) had SDB (respiratory event index [REI] ≥15/hour); and were significantly more often affected by CVD than patients without SDB (38% vs. 23%, p < 0.01; PAD 7% vs. 2%, p = 0.01; CAD 27% vs. 18%, p = 0.01; stroke 11% vs. 6%, p = 0.07). Regression analysis accounting for known modulators of CVD, such as age, body-mass index, systolic blood pressure, duration of DM2, HbA1c, smoking status, and low-density lipoprotein showed that the REI was independently associated with CVD (OR 1.099 per 5 REI points; 95%CI = [1.024, 1.179]).

CONCLUSIONS

In patients with DM2, SDB is significantly associated with CVD, independent of other known modulators of atherosclerosis.

Sleep duration and subclinical atherosclerosis: The Aragon Workers' Health Study

BACKGROUND AND AIMS

Few studies have evaluated the association of sleep duration with subclinical atherosclerosis, and with heterogeneous findings. We evaluated the association of sleep duration with the presence of coronary, carotid, and femoral subclinical atherosclerosis in healthy middle-age men with low prevalence of clinical comorbidities.

METHODS

We performed a cross-sectional analysis of 1968 men, 40-60 years of age, participating in the Aragon Workers' Health Study (AWHS). Duration of sleep during a typical work week was assessed by questionnaire. Coronary artery calcium scores (CACS) was assessed by computed tomography and the presence of carotid plaque and femoral plaque by ultrasound.

RESULTS

In fully adjusted models, the odds ratios (95% CI) for CACS >0 comparing sleep durations of ≤5, 6, and ≥8 h with 7 h were 1.34 (0.98-1.85), 1.35 (1.08-1.69) and 1.21 (0.90-1.62), respectively (p = 0.04). A similar U-shaped association was observed for CACS ≥100 and for CACS. The corresponding odds ratios for the presence of at least one carotid plaque were ≤5, 6, and ≥8 h with 7 h were 1.23 (0.88-1.72), 1.09 (0.86-1.38), and 0.86 (0.63-1.17), respectively (p = 0.31), and for the presence of at least one femoral plaque were 1.25 (0.87-1.80), 1.19 (0.93-1.51) and 1.17 (0.86-1.61), respectively (p = 0.39).

CONCLUSIONS

Middle-aged men reporting 7 h of sleep duration had the lowest prevalence of subclinical coronary atherosclerosis as assessed by CACs. Our results support that men with very short or very long sleep durations are at increased risk of atherosclerosis.

The Apnea-Hypopnea Index Underestimates Systemic Inflammation in Women with Sleep-Disordered Breathing

BACKGROUND

Evidence suggests that sleep-related respiratory and related metabolic compromise may vary between females and males with sleep-disordered breathing (SDB). Our purpose was to elucidate possible gender differences in sleep-associated respiratory and inflammatory parameters in patients with SDB.

MATERIALS AND METHODS

A consecutive number of SDB patients (46 females and 167 males) who underwent polysomnography were retrospectively reviewed. Fibrinogen and C-reactive protein (CRP) concentration, apnea index (ApnI), hypopnea index (HypI), apnea-hypopnea index (AHI), average and minimal SpO₂, duration of snoring, age, and body mass index (BMI) were compared between sexes. Spearman's ρ correlation coefficients between parameters were also calculated.

RESULTS

ApnI and AHI were significantly higher in males. Correlation analysis revealed striking gender differences: only in females, CRP concentration was highly correlated with snoring duration (r = 0.4393), BMI (r = 0.7147), minimal SpO₂ (r = -0.4357), and average SpO₂ (r = -0.4547); in females, HypI was more strongly correlated with AHI (r = 0.8778), average SpO₂ (r = -0.5765), minimal SpO₂ (r = -0.5817), and fibrinogen concentration (r = 0.4614) than in males (r = 0.4373; -0.3295; -0.2969; and 0.0887, respectively); in females, age had a much more pronounced effect on ApnI, HypI, AHI, average oxygen saturation (SaO₂), minimal SaO₂, snoring duration, and CRP and fibrinogen concentration.

CONCLUSIONS

Respiratory compromise in females with SDB is more strongly associated with systemic inflammation than in males with SDB. Although females display a pathological AHI less frequently than males, they reach quite similar pathological SaO₂, CRP, and fibrinogen values. Therefore, AHI may underestimate the pathophysiological systemic effects of SDB in females.

Genetic Ancestry for Sleep Research: Leveraging Health Inequalities to Identify Causal Genetic Variants

Recent evidence has highlighted the health inequalities in sleep behaviors and sleep disorders that adversely affect outcomes in select populations, including African-American and Hispanic-American subjects. Race-related sleep health inequalities are ascribed to differences in multilevel and interlinked health determinants, such as sociodemographic factors, health behaviors, and biology. African-American and Hispanic-American subjects are admixed populations whose genetic inheritance combines two or more ancestral populations originating from different continents. Racial inequalities in admixed populations can be parsed into relevant groups of mediating factors (environmental vs genetic) with the use of measures of genetic ancestry, including the proportion of an individual's genetic makeup that comes from each of the major ancestral continental populations. This review describes sleep health inequalities in African-American and Hispanic-American subjects and considers the potential utility of ancestry studies to exploit these differences to gain insight into the genetic underpinnings of these phenotypes. The inclusion of genetic approaches in future studies of admixed populations will allow greater understanding of the potential biological basis of race-related sleep health inequalities.