All-cause mortality in males with sleep apnoea syndrome: declining mortality rates with age

Sleep complaints in community-living older persons: a multifactorial geriatric syndrome

In older persons, sleep complaints in the form of insomnia and daytime drowsiness are highly prevalent and are associated with adverse outcomes. The underlying mechanisms are linked to age-related declines in physiology (normal aging) and age-related increases in disease prevalence (usual aging). This article describes how normal aging leads to less-restorative sleep, characterized by reductions in homeostatic and circadian sleep, and to phase advancement of the sleep-wake cycle, characterized by older persons being more alert in the early morning but drowsier in the early evening. It also describes how usual aging leads to sleep complaints through reductions in health status, loss of physical function, and primary sleep disorders. Psychosocial influences are likewise described, and their relevance to sleep complaints is discussed. These aging-related changes are subsequently incorporated into a conceptual model that describes sleep complaints as a consequence of multiple and interdependent predisposing, precipitating, and perpetuating factors, akin to a geriatric syndrome. The discussion concludes by applying the conceptual model to the sleep-related care of an older person with insomnia and daytime drowsiness and suggesting that the diagnostic assessment consider, in addition to primary sleep disorders, multiple domains, including medical, physical, cognitive, psychological, and social matters, with the intent of developing an overall therapeutic plan and establishing long-term follow-up.

Sleep apnea: epidemiology, pathophysiology, and relation to cardiovascular risk

Several studies have shown the occurrence of an independent association between obstructive sleep apnea syndrome (OSAS) and cardiovascular disease, including arterial hypertension, ischemic heart disease, and stroke. The pathogenesis of the cardiovascular complications of OSAS is still poorly understood, however. Several mechanisms are likely to be involved, including sympathetic overactivity, selective activation of inflammatory molecular pathways, endothelial dysfunction, abnormality in the process of coagulation, and metabolic dysregulation. The latter may involve insulin resistance and disorders of lipid metabolism. The aim of this review, which reports the data presented at a workshop jointly endorsed by the European Society of Hypertension and by the European Union COST action on OSAS (COST B26), is to critically summarize the evidence available to support an independent association between OSAS and cardiovascular disease.

Comparison of cognitive performance among different age groups in patients with obstructive sleep apnea

The aim of this study was to evaluate the effect of obstructive sleep apnea syndrome on the cognitive performance of young and middle-aged patients. Patients were divided into two groups, one consisting of 30 patients less than 50 years of age and the other consisting of 28 patients 50 years and over. Normal subjects were similarly divided into two groups, composed of 17 younger and 24 older controls. Patients and controls were examined with all-night polysomnography and subsequently underwent cognitive testing via attention-alertness tests. Comparing young to middle-aged patients, there were statistically significant differences in cognitive performance, especially in attention tests. Younger patients' cognitive performance was similar to their age-matched controls, while middle-aged patients showed cognitive decline in comparison with their age-matched controls. Although we studied only two age groups using 50 years of age as a cut-off, we could demonstrate that cognitive deterioration of untreated sleep apnea patients is age dependent, and several factors may contribute to this effect including brain hypoxia, sleep fragmentation, or comorbidities. Aging patients with sleep apnea demonstrate cognitive decline, while younger patients with the same disease severity are (somehow) able to compensate for this effect.

Continuous positive airway pressure treatment of mild to moderate obstructive sleep apnea reduces cardiovascular risk

RATIONALE

Obstructive sleep apnea (OSA) is linked to increased cardiovascular risk, but the impact of mild forms of OSA and their treatment on cardiovascular outcomes remains controversial.

OBJECTIVES

To prospectively investigate cardiovascular outcomes in treated versus untreated patients with OSA.

METHODS

Consecutive sleep laboratory patients with all degrees of OSA were included. Endpoints were nonfatal (myocardial infarction, stroke, and acute coronary syndrome requiring revascularization procedures) and fatal (death from myocardial infarction or stroke) cardiovascular events.

MEASUREMENTS AND MAIN RESULTS

Comparison of event-free survival rates in treated versus untreated patients (Kaplan-Meier estimates, log-rank test). Of 449 patients enrolled (age, 56.0 +/- 10.5 years; body mass index, 30.8 +/- 5.4 kg/m(2)), 364 patients received OSA treatment, and 85 patients remained untreated. Median follow-up was 72.0 months (range, 1-156). Mean apnea-hypopnea index before treatment was 30.9 +/- 21.8/hour in treated and 15.3 +/- 13.0/hour in untreated patients, but there were no differences in cardiovascular comorbidities or risk factors. In patients with mild-moderate OSA (n = 288), events were more frequent in untreated patients (estimated event-free survival at 10 yr, 51.8 vs. 80.3% [P < 0.001]; absolute risk reduction, 28.5%; number needed to treat to prevent one event/10 yr, 3.5). After adjustment for age, gender, cardiovascular risk factors, and comorbidities at baseline, OSA treatment was an independent predictor for events (hazard ratio, 0.36; 95% confidence interval, 0.21-0.62; P < 0.001).

CONCLUSIONS

OSA treatment was associated with a cardiovascular risk reduction of 64% independent from age and preexisting cardiovascular comorbidities. OSA treatment should be considered for primary and secondary cardiovascular prevention, even in milder OSA.

Home Sleep Testing in the Diagnosis and Treatment of Sleep Disordered Breathing

Sleep-disordered breathing is a growing public health concern and an integral part of head and neck surgery. Multichannel home sleep testing is a cost-effective, patient-friendly, scientifically valid technique of evaluating patients who present with symptoms of sleep-disordered breathing, typically snoring or daytime sleepiness. Home sleep tests can be dispensed from the physician's office. They have a 95% successful recording rate. Scoring can be autoscore or manual score. There are several protocols that can be followed based on diagnostic outcomes.

Sleep apnea: clinical investigations in humans

Sleep apnea syndrome (SAS), a common disorder, is characterized by repetitive episodes of cessation of breathing during sleep, resulting in hypoxemia and sleep disruption. The consequences of the abnormal breathing during sleep include daytime sleepiness, neurocognitive dysfunction, development of cardiovascular disorders, metabolic dysfunction, and impaired quality of life. There are two types of SAS: obstructive sleep apnea syndrome (OSAS) and central sleep apnea syndrome (CSAS). OSAS is a prevalent disorder in which there is snoring, repetitive apneic episodes, and daytime sleepiness. Anatomical conditions causing upper airway obstruction (obesity or craniofacial abnormalities such as retrognathia or micrognathia) can cause OSAS. CSAS, much less common than OSAS, is a disorder characterized by cessation of breathing which is caused by reduced respiratory drive from the central nervous system to the muscles of respiration. The latter condition is common in patients with heart failure and cerebral neurologic diseases. The diagnosis of SAS requires assessment of subjective symptoms and apneic episodes during sleep documented by polysomnography. Treatments of OSAS include continuous positive airway pressure (CPAP), oral appliances, and surgery; patients with CSAS are treated with oxygen, adaptive servo-ventilation, or CPAP. With assessment and treatment of the SAS, patients usually have resolution of their disabling symptoms, subsequently resulting in improved quality of life.

Sleep apnea in the elderly: a specific entity?

Sleep apnea is highly prevalent in subjects after age 60, and affects older men and women similarly. Central apneas are often observed in addition to obstructive and mixed events. Pathogenesis of obstructive and central events during sleep in the elderly can be attributed to an amplification of well-established causes of sleep-disordered breathing (SDB) in younger adults. As in middle-aged adults, sleep-related complaints, cardiovascular diseases, depression and traffic accidents should prompt an evaluation by a sleep specialist. However, secondary enuresis and nocturia, cognitive impairment, ophthalmic conditions and repeated falls may be the main complaint in elderly subjects. Sleep studies in the elderly should systematically include reliable means to detect central apneas and periodic leg movements. Untreated SDB in the elderly appears to have a lesser impact on mortality than in middle-aged adults. However, the typical morbidity associated with the disorder in younger adults is observed in the elderly. Elderly symptomatic SDB patients tolerate CPAP no differently than younger patients and should be effectively treated. In conclusion, whether sleep apnea in the elderly represents a specific entity or the same disease as in younger subjects, with some distinctive features, is still unclear. Further research, in particular focusing on the impact of age on SDB outcomes, is needed.

Intermittent hypoxia-induced delayed cardioprotection is mediated by PKC and triggered by p38 MAP kinase and Erk1/2

We previously reported that acute intermittent hypoxia (IH) confers delayed cardioprotection against a prolonged ischemic insult in the rat, via the involvement of nitric oxide synthase and K(ATP) channels. In the present study, we investigated the role of protein kinase C (PKC), phosphatidylinositol-3-kinase (PI3K), stress activated p38 MAP kinase (MAPK) and extracellular signal-regulated kinase (ERK1/2) using selective inhibitors of these pathways. Adult male rats were exposed to 1-min cycles of IH (10% O(2), 40 s)/normoxia (21% O(2), 20 s) during 4 h or to normoxic cycles. 24 h later, isolated hearts were perfused in Langendorff mode and subjected to a 30-min global ischemia followed by 120 min of reperfusion. Compared to normoxic conditions, IH significantly reduced infarct size (22.2+/-2.4% vs. 33.8+/-2.6%, p<0.05), improved coronary flow and decreased the contracture at reperfusion. When administered before sustained ischemia, chelerythrine (a PKC inhibitor) abolished both the IH-induced reduction in infarct size (36.1+/-4.9%) and improvement in hemodynamic parameters. In contrast, chelerythrine administration 10 min before IH, did not modify the delayed cardioprotective response. Similarly, wortmannin (a PI3K inhibitor) administration 10 min before IH was unable to block the cardioprotective effects. However, administration of SB203580 (a p38 MAPK inhibitor) and PD98059 (an Erk1/2 inhibitor), 30 min before IH abolished its delayed infarct-sparing effect (32.2+/-3.4% and 33.9+/-2.9%, respectively). In addition, 24 h after IH, a significant increase in p38 MAPK and Erk1/2 phosphorylation was observed by Western blot. These results suggest that the delayed preconditioning induced by intermittent hypoxia does not involve the PI3K signalling pathway and that is mediated by PKC and triggered by p38 MAPK and Erk1/2.

Association of Elevated Levels of Vascular Endothelial Growth Factor in Obstructive Sleep Apnea Syndrome with Patient Age rather than with Obstructive Sleep Apnea Syndrome Severity

BACKGROUND

Although certain studies report high levels of vascular endothelial growth factor (VEGF) in obstructive sleep apnea syndrome (OSAS), the effect of systemic hypoxia on circulating VEGF remains controversial.

OBJECTIVES

To study the association of serum VEGF and OSAS in a large group of patients.

METHODS

One hundred patients with OSAS (mean age 58.1+/-12.4 years, mean body mass index 30.6+/-5.4 kg/m2) were tested for serum VEGF levels, and the findings were correlated with the severity of OSAS, as determined by the apnea-hypopnea index (AHI) on the basis of polysomnography and background data.

RESULTS

The mean AHI was 40.0+/-21.2 (range 10-106). Mean minimal oxygen saturation was 80.6+/-11.7% (range 43-98%) and mean time of oxygen saturation under 90% was 50.0+/-75.0 min (range 0-300 min). The mean VEGF level was 445.2+/-289.8 pg/ml in the study group (vs. 280 pg/ml reported in normal controls). The mean platelet count was 233.8+/-64.4 10(3)/ml and the mean VEGF/platelet ratio was 1.95+/-1.40 pg/10(6). There was no association of VEGF or VEGF/platelets with the severity of OSAS. However, both factors showed a significant correlation with patient age (r=0.224, p=0.01 and r=0.425, p=0.01, respectively). Age was the only parameter to significantly predict VEGF and VEGF/platelets on multivariate analysis (R2=0.713, p=0.001 and R2=0.844, p=0.001, respectively).

CONCLUSION

The elevation of serum VEGF in OSAS is not associated with the severity of the disease, but it is associated with patient age. VEGF might be involved in the long-term adaptive mechanism in OSAS, and its age-dependent increase might partly explain the reduced mortality in elderly OSAS patients.

Prevalence of Symptoms and Risk of Sleep Apnea in the US Population

BACKGROUND

Obstructive sleep apnea (OSA) is a common medical condition with significant adverse consequences, but OSA remains undiagnosed in many individuals. The Berlin questionnaire is a validated instrument that is used to identify individuals who are at risk for OSA.

DESIGN

We conducted an analysis of data from the Sleep in America 2005 Poll of The National Sleep Foundation (NSF). The NSF poll is an annual telephone interview of a representative sample of US adults.

PARTICIPANTS

The 2005 NSF poll included 1,506 adults. The mean age of participants was 49 years (775 were women).

MEASUREMENTS

The Berlin questionnaire was embedded in the NSF poll. This instrument includes questions about snoring, witnessed apneas, self-reported hypertension, and daytime sleepiness. Height and weight were included for the calculation of body mass index (BMI). The NSF poll included detailed demographic information and extensive questions related to all aspects of sleep.

RESULTS

Of the 1,506 respondents, 26% (31% of men and 21% of women) met the Berlin questionnaire criteria indicating a high risk of OSA. The risk of OSA increased up to age 65 years. A significant number of obese individuals (57%) were at high risk for OSA. Those whose Berlin questionnaire scores indicated a high risk for OSA were more likely to report subjective sleep problems, a negative impact of sleep on quality of life, and a chronic medical condition than those who were at lower risk.

CONCLUSIONS

As many as one in four American adults could benefit from evaluation for OSA. Considering the serious adverse health and quality-of-life consequences of OSA, efforts to expedite diagnosis and treatment are indicated.

Severe sleep apnea and risk of ischemic stroke in the elderly

BACKGROUND AND PURPOSE

Convincing evidence of a causal relationship between sleep apnea and stroke has been shown recently in several prospective, well-designed studies. However, these studies have focused on middle-aged people, excluding the elderly population from analysis. To investigate whether sleep apnea represents an independent risk factor in this population, we performed a prospective longitudinal study in a population-based cohort of subjects from 70 to 100 years old.

METHODS

Within the context of the Vitoria Sleep Project, a population-based study designed to investigate the prevalence of sleep apnea in the population of Vitoria, Spain, we performed a 6-year longitudinal study in a subsample cohort of 394 noninstitutionalized, initially event-free subjects (70 to 100 years old, median 77.28 years, 57.1% males). Demographic and polysomnographic data and known confounding factors (age, sex, smoking and alcohol consumption status, body mass index, systolic and diastolic blood pressure, total serum cholesterol levels, and the presence or absence of diabetes mellitus, atrial fibrillation, and hypertension) were assessed at baseline. Hazard ratio for developing an ischemic stroke in relation to the apnea-hypopnea index at baseline was calculated.

RESULTS

Over the 6-year follow-up period, 20 ischemic strokes were registered. After adjustment for confounding factors, subjects with severe obstructive sleep apnea hypopnea (defined as apnea-hypopnea index >or=30) at baseline had an increased risk of developing a stroke (hazard ratio=2.52, 95% CI=1.04 to 6.01, P=0.04).

CONCLUSIONS

This study shows that severe obstructive sleep apnea hypopnea (defined as apnea-hypopnea index >or=30) increases the risk of ischemic stroke in the elderly population, independent of known confounding factors.

S100B and NSE serum levels in obstructive sleep apnea syndrome

BACKGROUND AND PURPOSE

Obstructive sleep apnea syndrome (OSAS) is a chronic disease ranging from innocuous to life-threatening and causes brain alterations manifested by neuropsychiatric symptoms. Neuron-specific enolase (NSE) and the astrocytic protein S100B are established sensitive peripheral biochemical markers of brain injury. In the present work we measured the serum levels of S100B and NSE in order to evaluate the deleterious effects of OSAS to the brain.

PATIENTS AND METHODS

We studied 29 male patients with OSAS and 17 male asymptomatic control subjects with an apnea-hypopnea index (AHI) less than five events per hour. Patients and control subjects were evaluated by full-night polysomnography (PSG) and by Mini International Neuropsychiatric Interview (MINI) for the presence of neuropsychiatric symptoms. In the morning following the PSG, blood was collected and serum levels of S100B and NSE were measured using standard techniques.

RESULTS

The AHI in the OSAS group was (mean+/-SD) 27+/-25 AH/h, ranging from 5 to 99 AH/h. S100B was higher in OSAS (0.15+/-0.09 microg/l) than in the control group (0.08+/-0.06 microg/l; P<0.01). Serum NSE was similar in both groups (17.5+/-12.2 vs. 15.8+/-6.8ng/ml).

CONCLUSIONS

We report elevated serum S100B levels in OSAS patients in this study.

Ischemic preconditioning as a possible explanation for the age decline relative mortality in sleep apnea

Breathing disorders in sleep are prevalent phenomena profoundly affecting the cardiovascular system. Mortality studies of sleep apnea patients revealed maximum risk of dying in younger patients and a pronounced age-decline in relative mortality reaching non significant levels in patients older than 50 years. We hypothesize that the age decline mortality risk in sleep apnea can be explained by cardiovascular and cerebrovascular protection conferred by ischemic preconditioning resulting from the nocturnal cycles of hypoxia-reoxygenation. The association of ischemic preconditioning with increase levels of vascular endothelial growth factor, increased production of oxygen reactive species, heat shock proteins, adenosine, and TNF-alpha, all demonstrated in sleep apnea, provide preliminary support to our hypothesis.