Natural history of sleep disordered breathing in community dwelling elderly

Progression of obstructive sleep apnoea after renal denervation is not associated with hypertension exaggeration

PURPOSE

In a cohort, observational prospective trial, we assessed the long-term dynamics of sleep-disordered breathing in patients with resistant hypertension after renal denervation and their association with blood pressure change at remote follow-up.

MATERIALS AND METHODS

Twenty-eight patients with stable hypertension who were recruited for endovascular radiofrequency renal denervation in 2012-2019 and had valid both baseline and follow-up sleep study, were included in the analysis. All patients underwent physical examination, anthropometry, office and ambulatory blood pressure measurements, blood and urine tests, kidney visualization, and full polysomnography before and within 12-36 months after renal denervation.

RESULTS

The average follow-up comprised 30.1 ± 8.4 months. At long-term follow-up, no significant changes in creatinine level, estimated glomerular filtration rate, body mass index were registered. There was a significant increase in sleep apnea severity indices: the mean change in apnea-hypopnea index comprised 9.0(-21.1;25.2) episodes/h, in oxygen desaturation index 6.5(-16.8;35.9) episodes/h, in the average SpO2 -1.7(-5.6;1.9)%. Over 12-month follow-up, there were no significant differences in blood pressure response in patients with and without sleep apnea. The baseline apnea-hypopnea and oxygen desaturation indices and the mean SpO2 were associated with the circadian blood pressure profile at follow-up, but did not correlate with the blood pressure response.

CONCLUSIONS

Although the severity of sleep apnea worsens at > 12 months follow-up after renal denervation, this is not associated with hypertension exaggeration.

Should mild obstructive sleep apnoea be treated? A systematic review from the standpoint of disease progression

OBJECTIVE

This study was a systematic review to investigate the progression of untreated obstructive sleep apnoea in order to evaluate whether mild obstructive sleep apnoea should be treated from the standpoint of disease progression.

METHOD

The database search study outcomes that were collected included Apnea Hypopnea Index and Respiratory Disturbance Index. A meta-analysis of obstructive sleep apnoea severity over time intervals was performed.

RESULTS

A total of 17 longitudinal studies and 1 randomised, controlled trial were included for review. For patients with mild obstructive sleep apnoea, mean pre-study and post-study Apnea Hypopnea Index was 5.21 and 8.03, respectively, over a median interval of 53.1 months. In patients with moderate to severe obstructive sleep apnoea, mean pre-study and post-study Apnea Hypopnea Index was 28.9 and 30.3, respectively, over a median interval of 57.8 months. Predictors for disease progression in mild obstructive sleep apnoea are patients aged less than 60 years and those with a baseline body mass index less than 25.

CONCLUSION

Mild obstructive sleep apnoea progression is observed, but it does not appear to reach any clinically significant progression to moderate or severe obstructive sleep apnoea.

The Effect of Obstructive Sleep Apnea on Sleep-dependent Emotional Memory Consolidation

Rationale: A growing body of evidence suggests that sleep is critical for the adaptive processing and consolidation of emotional information into long-term memory. Previous research has indicated that emotional components of scenes particularly benefit from sleep in healthy groups, yet sleep-dependent emotional memory processes remain unexplored in clinical cohorts, including those with obstructive sleep apnea (OSA). This line of research is important as it will add to the understanding of how disrupted sleep in OSA contributes to both impaired cognition and emotion dysregulation. Objectives: To test the hypothesis that individuals with OSA will have impaired sleep-dependent memory consolidation, with the greatest impact being on memory for emotional content. Methods: In this study, a group of newly diagnosed patients with OSA (n = 26; 10 female; average age, 42.5 years) and a matched group of healthy control subjects (n = 24; 13 female; average age, 37 years) were enrolled in the study at Beth Israel Deaconess Medical Center. Participants encoded scenes with negative or neutral foreground objects placed on neutral backgrounds before a night of polysomnographically recorded sleep. In the morning, they completed a recognition test in which old and new scene objects and backgrounds, presented separately and one at a time, were judged as old, new, or similar compared with what had been previously viewed. Results: Patients with OSA had a deficit in recognition memory for the scenes. Overall recognition (the ability to recognize old items as either old or similar) was impaired across all scene elements, both negative and neutral objects and backgrounds, whereas specific recognition (correctly identifying old items as old) was impaired only for negative objects. Across all participants, successful overall recognition correlated positively with sleep efficiency and rapid eye movement (REM) sleep, whereas successful specific memory recognition correlated only with REM sleep. Conclusions: Our findings indicate that fragmented sleep and reduced REM sleep, both hallmarks of OSA, are associated with disruptions in general memory impairment and veridical memory for emotional content, which could alter emotional regulation and contribute to comorbid emotional distress in OSA.

Sleep Health and Road Safety: Continuation of Asia-Pacific Economic Cooperation Sleep Technology Agenda

In 2017, the Asia-Pacific Economic Cooperation Sleep Technology Agenda emphasized the impacts of sleep health on road safety. An official meeting between the Department of Transportation of United States and the International Sleep Science and Technology Association took place in Washington, DC, on February 3, 2020. This was followed by several meetings in Taiwan advocated by the International Sleep Science and Technology Association Taiwan Chapter. We hope to raise the awareness in the government sectors, and to provide the scientific evidence of verified sleep and fatigue-monitoring technologies to avoid numerous tragedies on the road from its root cause.

Impact of Poor Sleep on Physical and Mental Health in Older Women

Many aspects of sleep and circadian rhythms change as people age. Older adults usually experience decrease in sleep duration and efficiency, increase in sleep latency and fragmentation, high prevalence of sleep disorders, and weakened rest-activity rhythms. Research evidence suggests that women are more likely to report aging-related sleep problems. This review presents epidemiologic and clinical evidence on the relationships between sleep deficiency and physical and mental outcomes in older women, explores potential mechanisms underlying such relationships, points out gaps in the literature that warrant future investigations, and considers implications in clinical and public health settings.

APOEε4 and slow wave sleep in older adults

Slow wave (or stage N3) sleep has been linked to a variety of cognitive processes. However, the role of stage N3 in the elderly is debated. The link between stage N3 and episodic memory may be weakened or changed in the older adult population, possibly due to several altered mechanisms impacting the cellular structure of the brain. The bases for the age-related dissociation between stage N3 and cognition are not understood. Since APOEε4 status is the strongest genetic risk factor for cognitive decline, we assessed whether the ε4 allele is associated with stage N3 sleep. Participants were from the population-based Osteoporotic Fractures in Men (MrOS) cohort with polysomnography and APOEε4 genotype data (n = 2,302, 100% male, mean age 76.6 years). Sleep stages were objectively measured using overnight in-home polysomnography and central electroencephalogram data were used to score stage N3 sleep. Cognitive function was assessed using the Modified Mini Mental State Exam (3MS). The APOE rs429358 single nucleotide polymorphism, which defines the APOEε4 allele, was genotyped using a custom genotyping array. Total time in stage N3 sleep was significantly higher (p<0.0001) among the 40 MrOS participants carrying two copies of the ε4 allele (62±5.2 minutes) compared with 43±1.5 minutes for carriers of one ε4 allele (n = 515) and 40±0.8 minutes for ε4 non-carriers (n = 1747). All results were independent of sleep efficiency, number of sleep cycles, and apnea hypopnea index. These findings support an association between APOEε4 genotype and sleep stage N3 in the elderly. Increased total stage N3 duration among ε4/ε4 carriers does not appear to reflect compensation for prior cognitive decline and may reflect overactive downscaling of synapses during sleep. If confirmed, these results might in part explain the high risk of age-related cognitive decline and AD among APOE ε4/ε4 carriers.

Three-year changes of prothrombotic factors in a cohort of South Africans with a high clinical suspicion of obstructive sleep apnea

A hypercoagulable state might be one important mechanism linking obstructive sleep apnea (OSA) with incident myocardial infarction and stroke. However, previous studies on prothrombotic factors in OSA are not uniform and cross-sectional. We longitudinally studied prothrombotic factors in relation to OSA risk, adjusting for baseline levels of prothrombotic factors, demographics, metabolic parameters, aspirin use, and life style factors. The Berlin Questionnaire and/or neck circumference were used to define high OSA risk in 329 South African teachers (48.0% male, 44.6% black) at baseline and at three-year follow-up. Von Willebrand factor (VWF), fibrinogen, D-dimer, plasminogen activator inhibitor-1, clot lysis time (CLT), and soluble urokinase-type plasminogen activator receptor (suPAR) were measured in plasma. At baseline 35.7% of participants had a high risk of OSA. At follow-up, persistently high OSA risk, persistently low OSA risk, OSA risk remission, and new-onset OSA risk were present in 26.1%, 53.2%, 9.4%, and 11.3% of participants, respectively. New-onset OSA risk was associated with a significant and longitudinal increase in VWF, fibrinogen, CLT, and suPAR relative to persistently low OSA risk; in VWF, fibrinogen, and suPAR relative to remitted OSA risk; and in VWF relative to persistently high OSA risk. Persistently high OSA risk was associated with an increase in CLT and suPAR relative to persistently low OSA risk and in D-dimer relative to remitted OSA risk. Remitted OSA risk was associated with D-dimer decrease relative to persistently low OSA risk. In OSA, hypercoagulability is a dynamic process with a most prominent three-year increase in individuals with new-onset OSA risk.

Obstructive sleep apnea and type 2 diabetes in older adults

Both obstructive sleep apnea (OSA) and type 2 diabetes mellitus are commonly seen in older adults. Over the last decade, there has been increasing recognition that OSA is highly prevalent in persons with type 2 diabetes and related metabolic conditions such as insulin resistance and glucose intolerance. Intermittent hypoxemia and recurrent arousals in OSA trigger a repertoire of pathophysiological events, which can in turn alter glucose homeostasis and possibly increase the risk for type 2 diabetes. Conversely, there is evidence that type 2 diabetes may alter the progression and expression of sleep-disordered breathing.

[Obstructive sleep apnea syndrome in the elderly]

Obstructive sleep apnea/hypopnea syndrome (OSAHS) is a common disease in the general population. However, original works on the SAHS in the elderly are few and their results are discordant. Studies show an increased prevalence of OSAHS with age, and despite this high prevalence, it remains under-diagnosed due to lack of knowledge of geriatric features of this disease and the frequency of comorbidities that may worsen as a result of nocturnal breathing problems but can also mask the symptoms necessary for positive diagnosis. The functional symptoms are dominated by neurological signs such as daytime hypersomnia and cognitive impairment often reported by those around the patient. The treatment is based mainly on continuous positive airway pressure which tolerance in elderly patients suffering from sleep apnea is similar to that of younger patients. Mandibular implants can be discussed depending on the severity of the condition. Surgical treatment is not indicated because of the increased frequency of complications.

Untreated sleep-disordered breathing: links to aging-related decline in sleep-dependent memory consolidation

BACKGROUND

Increasing age is associated with a decline in cognition and motor skills, while at the same time exacerbating one's risk of developing obstructive sleep apnea (OSA). OSA-related cognitive deficits are highly prevalent and can affect various memory systems including overnight memory consolidation on a motor sequence task. Thus, the aim of our study was to examine the effect of aging on sleep-dependent motor memory consolidation in patients with and without OSA.

METHODS

We studied 44 patients (19-68 years) who had been referred by a physician for a baseline polysomnography (PSG) evaluation. Based on their PSG, patients were assigned either to the OSA group (AHI>5/h), or control (Non-OSA) group (AHI<5/h). All subjects performed the Psychomotor Vigilance Task (PVT) and the Motor Sequence Learning Task (MST) in the evening and again in the morning after their PSG.

RESULTS

Despite similar learning in the evening, OSA subjects showed significantly less overnight improvement on the MST, both for immediate (OSA -2.7% ± 2.8% vs. controls 12.2% ± 3.5%; p = 0.002) and plateau improvement (OSA 4.9% ± 2.3% vs. controls 21.1%± 4.0%; p = 0.001). Within the OSA group, there was a significant negative correlation between overnight MST improvement and age (r(2) = 0.3; p = 0.01), an effect that was not observed in the Non-OSA group (r(2) = 0.08; p = 0.23).

CONCLUSIONS

Consistent with previous research, healthy sleepers demonstrated a higher degree of sleep-dependent overnight improvement on the MST, an effect not mitigated by increasing age. However, the presence of untreated obstructive sleep apnea is associated with an aging-related cognitive deficit, otherwise not present in individuals without OSA. As other research has linked the presence of OSA to a higher likelihood of developing dementia, future studies are necessary to examine if the inhibition of memory consolidation is tied to the onset of neurodegenerative disease.

[Portable sleep monitoring in patients with disorders in falling asleep or maintaining sleep]

BACKGROUND

The most common diagnoses in sleep medicine are insomnia, sleep disordered breathing (SDB) and periodic leg movements (PLM). These disorders may coincide. This study examined the role of portable sleep monitoring in the diagnostic process and which sleep medicine diagnoses are additionally found in patients with disorders of initiating and maintaining sleep.

METHODS

A total of 217 patients, including 103 men (47.5%) and 114 (52.5%) women aged 52.2 ± 13.6 years with disorders of initiating or maintaining sleep were included in the study. Patients with known SDB were excluded. Patients were investigated using a stepwise diagnostic procedure with clinical interviews, questionnaires, clinical examination and portable sleep recording with electromyography (EMG) of the tibialis anterior muscle to diagnose SDB and PLM.

RESULTS

Of the patients 125 (57.6%) were diagnosed with insomnia according to the International Classification of Sleep Disorders (ICSD) and 70 (56%) had no other sleep disorder. Out of the 217 patients SDB was found in 107 (49.3%) patients, PLM in 90 patients (41.5%) and in 78 patients (35.9%) restless legs syndrome (RLS) was diagnosed. Among the 125 patients with insomnia 44 patients had RLS/PLMD and 35 had SDB in addition whereas SDB and RLS/PLMD were found in 33 subjects. All 3 disorders insomnia, RLS/PLMD and SDB were found in 24 subjects.

CONCLUSIONS

Out of 217 patients with a complaint of non-restorative sleep only 125 were finally diagnosed with insomnia. As 25.3% of patients showed combinations of sleep disorders, 49.3% with SDB and 41.5% with RLS/PLMD portable monitoring with electromyography of the legs is recommended. The investigation with a portable sleep monitoring system including an EMG of the tibialis muscle is very useful in patients with insomnia in addition to a clinical interview and questionnaires.

[Aging of the respiratory system: anatomical changes and physiological consequences]

The respiratory system undergoes progressive involution with age, resulting in anatomical and functional changes that are exerted on all levels. The rib cage stiffens and respiratory muscles weaken. Distal bronchioles have reduced diameter and tend to be collapsed. Mobilized lung volumes decrease with age while residual volume increases. Gas exchanges are modified with a linear decrease of PaO(2) up to the age of 70 years and a decreased diffusing capacity of carbon monoxide. Ventilatory responses to hypercapnia, hypoxia and exercise decrease in the elderly. Knowledge of changes in the respiratory system related to advancing age is a medical issue of great importance in order to distinguish the effects of aging from those of diseases.

Sleep and sleep disorders in older adults

A common but significant change associated with aging is a profound disruption to the daily sleep-wake cycle. It has been estimated that as many as 50% of older adults complain about difficulty initiating or maintaining sleep. Poor sleep results in increased risk of significant morbidity and mortality. Moreover, in younger adults, compromised sleep has been shown to have a consistent effect on cognitive function, which may suggest that sleep problems contribute to the cognitive changes that accompany older age. The multifactorial nature of variables affecting sleep in old age cannot be overstated. Changes in sleep have been thought to reflect normal developmental processes, which can be further compromised by sleep disturbances secondary to medical or psychiatric diseases (e.g., chronic pain, dementia, depression), a primary sleep disorder that can itself be age-related (e.g., Sleep Disordered Breathing and Periodic Limb Movements During Sleep), or some combination of any of these factors. Given that changes in sleep quality and quantity in later life have implications for quality of life and level of functioning, it is imperative to distinguish the normal age-related sleep changes from those originating from pathological processes.

Obstructive sleep apnea syndrome: natural history, diagnosis, and emerging treatment options

Sleep apnea is an entity characterized by repetitive upper airway obstruction resulting in nocturnal hypoxia and sleep fragmentation. It is estimated that 2%-4% of the middle-aged population has sleep apnea with a predilection in men relative to women. Risk factors of sleep apnea include obesity, gender, age, menopause, familial factors, craniofacial abnormalities, and alcohol. Sleep apnea has been increasingly recognized as a major health burden associated with hypertension and increased risk of cardiovascular disease and death. Increased airway collapsibility and derangement in ventilatory control responses are the major pathological features of this disorder. Polysomnography (PSG) is the gold-standard method for diagnosis of sleep apnea and assessment of sleep apnea severity; however, portable sleep monitoring has a diagnostic role in the setting of high pretest probability sleep apnea in the absence of significant comorbidity. Positive pressure therapy is the mainstay therapy of sleep apnea. Other treatment modalities, such as upper airway surgery or oral appliances, may be used for the treatment of sleep apnea in select cases. In this review, we focus on describing the sleep apnea definition, risk factor profile, underlying pathophysiologic mechanisms, associated adverse consequences, diagnostic modalities, and treatment strategies.

Incident sleep disordered breathing in old age

BACKGROUND

Little is known about progression of and risk factors for sleep disordered breathing (SDB) in old age. We prospectively examined elderly volunteers to understand how changes in body weight are related to SDB for a period of 20-30 years.

METHODS

Participants were 30 surviving members of a community-based cohort (mean entry age = 57.8) studied over a median follow-up of 23.4 years. SDB was quantified as the apnea-hypopnea index (AHI) via in-lab polysomnography from 215 nights, representing 733.3 person-years of follow-up. Weights were recorded in kilograms. We used linear regression to derive individual trajectories of AHI and weight regressed on time.

RESULTS

Individuals had relatively low AHI (X = 2.3 [SD = 3.5]) and body mass index (kg/m(2); X = 24.6 [SD = 4.6]) at entry. Rates of change in AHI were characterized by positive slopes and linear increases by least squares regression. Mean rate of change was +0.43 events per hour per year, a 3.3% yearly increase relative to the maximum AHI observed for each case. Within individuals, curve fitting indicated statistically significant AHI increases associated not only with increases, but also decreases, in weight.

CONCLUSIONS

Rates of increase in AHI were larger than for aging reported for other organ systems (eg, autonomic, musculoskeletal, and respiratory), possibly reflecting complex mechanistic determination of SDB in old age. Association between decreased weight and increased SDB with advancing years represents an important "proof of concept," perhaps compatible with failure to maintain airway patency during sleep as a component of generalized muscle weakness in old age.

EPIDEMIOLOGY OF AGE-DEPENDENCE IN SLEEP DISORDERED BREATHING (SDB) IN OLD AGE: THE BAY AREA SLEEP COHORT (BASC)

Sleep Disordered Breathing (SDB) is highly prevalent in elderly populations and is thought to reflect, at least in part, age-dependence. Several studies suggest that SDB in elderly populations may hold different functional outcomes relative to SDB in middle-aged populations. Risk factors for SDB specific for the elderly remain uncertain. In this report, we examined changes in SDB, body weight and pulmonary function in 103 individuals over an average interval of 7 years to determine whether changes in these measures covaried. In-lab polysomnography was performed on members of an elderly cohort (Bay Area Sleep Cohort) on two separate occasions (Time 1, Time 2) with multiple nights of measurement typically made on each occasion. Results indicated that: a) SDB progressed over time in both men and women; b) changes in body weight were unrelated to the progression in SDB; c) relative declines in lung volumes (Forced Vital Capacity, Forced Expiratory Volume in 1.0 second) were associated with relative increases in SDB, with the effects slightly stronger in men. These data suggest that age-dependence in one commonly ascribed aging biomarker (lung function) were coupled to increments in SDB. Maintenance of healthy lung function into old age may confer some protective benefits in the development of age-dependent SDB.

Behavioural characteristics associated with dementia assessment referrals in adults with Down syndrome

BACKGROUND

Behavioural changes associated with dementia in Down syndrome are well documented, yet little is known about the effect of such behaviours on carers and referral. By comparing the behavioural and cognitive profiles of individuals referred for a dementia assessment with those of individuals not referred, some insight can be gained into behavioural characteristics that initiate referral for specialist support or interventions.

METHOD

Forty-six adults with Down syndrome were divided into two groups dependent upon method of entry into the study; post-referral to a specialist service for older adults with intellectual disabilities and Down syndrome for a dementia assessment (n = 17) or after receiving information sent out to day centres and residential homes (n = 29). These groups were compared on established measures of dementia alongside two informant measures of behaviour.

RESULTS

Those referred for a dementia assessment evidenced scores indicative of cognitive decline on both informant and direct Neuropsychological Assessments and showed more behavioural excesses, but not deficits, and lower socialisation and coping skills than those in the comparison group. Carers of those referred for a dementia assessment reported a greater impact of behavioural excesses on staff than on the individual showing the behaviour in contrast to the comparison group.

CONCLUSION

The behavioural differences between those referred and the comparison group suggest that two factors are involved in the instigation of a referral for a dementia assessment: the nature of the behavioural presentation (excesses rather than deficits) and the effect of that behavioural change upon the care staff.

Prevalence and correlates of sleep-disordered breathing in older men: osteoporotic fractures in men sleep study

OBJECTIVES

To determine the prevalence and distribution of sleep-disordered breathing and associated correlates in a large cohort of older men using several standardized definitions.

DESIGN

Cross-sectional analyses.

SETTING

Six U.S. communities.

PARTICIPANTS

Polysomnography was performed on 2,911 participants of the Outcomes of Sleep Disorders in Older Men Sleep Study (mean age+/-standard deviation 76.38+/-5.53; body mass index 27.17+/-3.8 kg/m(2)).

MEASUREMENTS

Three outcomes were assessed: sleep-disordered breathing (respiratory disturbance index > or =15), obstructive apnea (obstructive apnea index > or =5), and central apnea (central apnea index > or =5).

RESULTS

The prevalence of moderate-severe sleep-disordered breathing was estimated to be 21.4% to 26.4%. Multivariable logistic regression models demonstrated that age (adjusted odds ratio (AOR) per 5-year increase =1.24, 95% confidence interval (CI)=1.15-1.34), obesity (AOR=2.54, 95% CI=2.09-3.09), Asian versus Caucasian race (AOR=2.14, 95% CI=1.33-3.45), snoring (AOR=2.01, 95% CI=1.62-2.49), sleepiness (AOR=1.41, 95% CI=1.11-1.79), hypertension (AOR=1.26, 95% CI=1.06-1.50), cardiovascular disease (AOR=1.24, 95% CI=1.19-1.29), and heart failure (AOR=1.81, 1.31-2.51) were independently associated with sleep-disordered breathing; snoring (AOR=2.10, 95% CI=1.67-2.70), age (AOR per 5-year increase=1.27, 95% CI=1.18-1.38), obesity (AOR=1.48, 95% CI=1.21-1.82), and heart failure (AOR=1.60, 95% CI=1.15-2.24) were associated with obstructive apnea; and age (AOR=1.33, 1.17-1.50) and heart failure (AOR=1.88, 95% CI=1.17-3.04) were associated with central apnea.

CONCLUSION

Regardless of definition, a high prevalence of sleep disorders is observed in community-dwelling older men. Qualitatively similar associations were observed between sleep disorders and snoring, obesity, and comorbidities, as reported for middle aged populations. Asian race was associated with sleep-disordered breathing.

Poor sleep is associated with impaired cognitive function in older women: the study of osteoporotic fractures

BACKGROUND

The association between objectively measured sleep and cognition among community-dwelling elderly persons remains understudied. This observational, cross-sectional analysis examined this association.

METHODS

Results are from 2932 women (mean age 83.5 years) in the Study of Osteoporotic Fractures between 2002 and 2004. Cognitive function was measured by Mini-Mental State Examination (MMSE) and Trail Making B Test (Trails B). Cognitive impairment was defined as MMSE < 26 or Trails B > 278 seconds. Sleep parameters measured objectively using actigraphy included total sleep time, sleep efficiency, sleep latency, wake after sleep onset (WASO), and total nap time.

RESULTS

There were 305 women (10.6%) with MMSE < 26 and 257 women (9.3%) with Trails B > 278 seconds. Compared with women with sleep efficiency > or = 70%, those with <70% had a higher risk of cognitive impairment (MMSE < 26 multivariate odds ratio [MOR] = 1.61; 95% confidence interval [CI], 1.20-2.16; Trails B > 278 MOR = 1.96; 95% CI, 1.43-2.67). Higher sleep latency was associated with higher risk of cognitive impairment (per half hour: MMSE < 26 MOR = 1.23; 95% CI, 1.13-1.33; Trails B > 278 MOR = 1.13; 95% CI, 1.04-1.24), as was higher WASO (per half hour: MMSE < 26 MOR = 1.15; 95% CI, 1.06-1.23; Trails B > 278 MOR = 1.24; 95% CI, 1.15-1.34). Women who napped > or = 2 hours per day had a higher risk (MMSE < 26 MOR = 1.42; 95% CI, 1.05-1.93; Trails B > 278 MOR = 1.74; 95% CI, 1.26-2.40). There was no significant relationship for total sleep time.

CONCLUSION

Objectively measured disturbed sleep was consistently related to poorer cognition, whereas total sleep time was not. This finding may suggest that it is disturbance of sleep rather than quantity that affects cognition.

Age-dependent associations between sleep-disordered breathing and hypertension: importance of discriminating between systolic/diastolic hypertension and isolated systolic hypertension in the Sleep Heart Health Study

BACKGROUND

Sleep-disordered breathing (SDB) is associated with hypertension in the middle-aged. The association is less clear in older persons. Most middle-aged hypertensives have systolic/diastolic hypertension, whereas isolated systolic hypertension (ISH) is common among persons over 60 years. Mechanistically, only systolic/diastolic hypertension is expected to be associated with SDB, but few studies of SDB and hypertension distinguish systolic/diastolic hypertension from ISH. Prior investigations may have underestimated an association between SDB and systolic/diastolic hypertension in the elderly by categorizing individuals with ISH as simply hypertensive.

METHODS AND RESULTS

We conducted cross-sectional analyses of 6120 participants in the Sleep Heart Health Study, stratified by age: 40 to 59 (n=2477) and > or =60 years. Outcome measures included apnea-hypopnea index (AHI; average number of apneas plus hypopneas per hour of sleep), systolic/diastolic hypertension (> or =140 and > or =90 mm Hg), and ISH (> or =140 and <90 mm Hg). With adjustment for covariates, ISH was not associated with SDB in either age category. In those aged<60 years, AHI was significantly associated with higher odds of systolic/diastolic hypertension (AHI 15 to 29.9, OR=2.38 [95% CI 1.30 to 4.38]; AHI > or =30, OR=2.24 [95% CI 1.10 to 4.54]). Among those aged > or =60 years, no adjusted association between AHI and systolic/diastolic hypertension was found.

CONCLUSIONS

SDB is associated with systolic/diastolic hypertension in those aged <60 years. No association was found between SDB and systolic/diastolic hypertension in those aged > or =60 years or between SDB and ISH in either age category. These findings have implications for SDB screening and treatment. Distinguishing between hypertensive subtypes reveals a stronger association between SDB and hypertension for those aged <60 years than previously reported.

Comparing night-to-night variability of sleep measures in elderly African Americans and Whites

There has been great interest in the night-to-night variability of sleep-disordered breathing because of the implications for the accuracy and costs associated with diagnostic testing. Night-to-night variability of sleep and respiratory parameters were examined in 66 older Whites and 56 older African Americans. Each participant had his or her sleep recorded for 2 nights with portable recording equipment. The correlations between the 2 nights were all large. Analyses of variance showed that men had a greater change in apnea index and in number of apneas than women. There were no differences in the parameters for African Americans versus Whites. One night of sleep recording may be sufficient for studying sleep disorders in elderly persons.

Genomic approaches to understanding obstructive sleep apnea

Obstructive sleep apnea (OSA) is an increasingly recognized, common chronic disease in the developed nations and is a complex disease that has high social and economic costs. OSA and its associated 'intermediate' phenotypes-craniofacial structure, body fat distribution and metabolism, and neurological control of the upper airway muscles and of sleep and circadian rhythm-are under a substantial degree of genetic control. Investigating the genetic aetiology of OSA offers a means of better understanding its pathogenesis, with the goal of improving preventive strategies, diagnostic tools and therapies. Molecular studies of OSA itself are in their infancy, but considerable effort and expense has already been expended in attempts to detect genetic loci contributing to OSA-associated intermediate phenotypes, such as obesity. However, many of the fundamental questions relating to the genetic epidemiology of OSA and associated factors remain unanswered. This chapter reviews the current state of knowledge of the genetics of OSA, with a focus on genomic approaches to understanding sleep disorders.

Prevalence and predictors of upper airway obstruction in the first 24 hours after acute stroke

BACKGROUND AND PURPOSE

The prevalence of sleep-disordered breathing after stroke has been reported to be between 32% and 71%. However, the first 24-hour period, when upper airway obstruction may have a critical effect on the cerebral circulation because of hemodynamic fluctuations and repetitive hypoxia, has not been studied. Furthermore, data on prediction of upper airway obstruction after stroke are limited. This study sought to assess the prevalence of upper airway obstruction in the first 24 hours of stroke and to ascertain whether its occurrence could be predicted.

METHODS

One hundred twenty patients with acute stroke underwent a respiratory variable-only sleep study, started within 24 hours of onset of neurological symptoms. Sleep history and stroke characteristics were recorded on admission.

RESULTS

We found that 79%, 61%, and 45% of the patients had a respiratory disturbance index greater than 5, 10, and 15 events per hour, respectively. Patients had a significantly higher respiratory disturbance index when nursed in the supine (29 events per hour), supine left (29 events per hour), and supine right (24 events per hour) positions than in any other position (P<0.0001). On logistic regression analysis, BMI (P=0.025), neck circumference (P=0.026), and limb weakness (P=0.025) independently predicted the occurrence of upper airway obstruction in the first 24 hours after acute stroke.

CONCLUSIONS

Upper airway obstruction is common in the first 24 hours after stroke, especially if patients are nursed in the supine position, and typical obstructive sleep apnea risk factors (body mass index and neck circumference) appear to be the best predictors of its occurrence. Stroke characteristics (severity, clinical subtype, and clinically assessed pharyngeal function) are not independently associated with upper airway obstruction after stroke.

Increased physician-reported sleep apnea: the National Ambulatory Medical Care Survey

BACKGROUND

Despite increased recognition of sleep apnea as a major health problem, little is known about physician practice patterns regarding this condition.

METHODS

We used the National Ambulatory Medical Care Survey (NAMCS) data between the years of 1990 to 1998, a weighted estimate of the frequency of physicians' diagnoses nationwide in their outpatient practices, to address the following questions: (1) has there been an increase in physician reporting of sleep apnea, (2) which physicians reported diagnoses of sleep apnea, and (3) what are the demographic characteristics of patients with diagnoses of sleep apnea?

RESULTS

During this 9-year period, there was a 12-fold increase in the diagnosis of sleep apnea in outpatients, from 108,121 to 1,305,624 diagnoses (p < 0.001). Among other primary sleep disorders, only insomnia had an increase in reporting (fourfold, p < 0.001). Report of sleep apnea was greatest among primary care providers (37%), pulmonologists (24%), and otolaryngologists (18%). Sleep apnea was reported more often in men than in women (3:1, respectively), and 80% of diagnoses occurred in the following age groups: 30 to 39 years (12%), 40 to 49 years (33%), 50 to 59 years (27%), and 60 to 69 years (12%). Conditions associated with sleep apnea included hypertension (10%), obesity (6%), and COPD (7%). Increased reporting of sleep apnea by NAMCS physicians was associated with increases in the number of accredited sleep laboratories and the number of sleep publications in the medical literature during the period of review (p < 0.001).

CONCLUSION

Sleep apnea is recognized increasingly by physicians. Further investigation is necessary to define those factors that influence physician recognition and reporting of sleep apnea, and approaches associated with optimum patient outcomes.

Long-term follow-up of untreated patients with sleep apnoea syndrome

Obstructive sleep apnoea (OSA) is a common disorder with numerous potential sequelae. Although the majority of these consequences can be reduced with appropriate treatment, only limited data exist regarding the natural progression ofthis disorder in untreated individuals. We hereby report a long-term follow-up of all untreated patients (n = 40) followed-up in the Technion Sleep Clinic, using both subjective and objective measurements. In addition, we report a long-term follow-up of 11 patients who attempted dietary weight loss. The average time interval between the first and second polysomnographies for the untreated group was 5.0 +/- 2.8 yrs, and 2.5 +/- 2.3 yrs for the weight reduction group. There was no significant change in Body Mass Index (BMI) or Respiratory Disturbance Index (RDI) between the two Polysomnographic (PSG) evaluations in the untreated patients. However, eight patients developed hypertension (n=5) or ischaemic heart disease (IHD) (n=3) between the two evaluations. RDI, age and BMI at the time ofthe initial evaluation were not predictive of changes in RDI, snoring intensity or minimal oxygen saturation. However, the patients who developed hypertension/IHD had significantly higher RDI than the patients who did not (46 +/- 27 vs. 23 +/- 17 h(-1), P < 0.005). In the weight-loss group, BMI decreased by a mean of 3.1 kg m(-2), and RDI decreased by 20events h(-1), P<0.05 for both. There was a significant correlation between the weight loss and improvement in RDI (R = 0.75, P = 0.005). We conclude that in untreated obstructive sleep apnoea patients RDI does not necessarily increase over time, but associated hypertension or ischaemic heart disease may develop. When weight loss is successfully achieved, sleep apnoea significantly improves with a high correlation between the extent of weight loss and the improvement in apnoea status.

Epidemiology of obstructive sleep apnea: a population health perspective

Population-based epidemiologic studies have uncovered the high prevalence and wide severity spectrum of undiagnosed obstructive sleep apnea, and have consistently found that even mild obstructive sleep apnea is associated with significant morbidity. Evidence from methodologically strong cohort studies indicates that undiagnosed obstructive sleep apnea, with or without symptoms, is independently associated with increased likelihood of hypertension, cardiovascular disease, stroke, daytime sleepiness, motor vehicle accidents, and diminished quality of life. Strategies to decrease the high prevalence and associated morbidity of obstructive sleep apnea are critically needed. The reduction or elimination of risk factors through public health initiatives with clinical support holds promise. Potentially modifiable risk factors considered in this review include overweight and obesity, alcohol, smoking, nasal congestion, and estrogen depletion in menopause. Data suggest that obstructive sleep apnea is associated with all these factors, but at present the only intervention strategy supported with adequate evidence is weight loss. A focus on weight control is especially important given the expanding epidemic of overweight and obesity in the United States. Primary care providers will be central to clinical approaches for addressing the burden and the development of cost-effective case-finding strategies and feasible treatment for mild obstructive sleep apnea warrants high priority.

Genetics of the apnea hypopnea index in Caucasians and African Americans: I. Segregation analysis

Differences in age of presentation and anatomic risk factors for obstructive sleep apnea (OSA) in Caucasians and African Americans suggest possible racial differences in the genetic underpinnings of the disorder. In this study, we assess transmission patterns in a Caucasian sample consisting of 177 families (N = 1,195) and in an African American sample consisting of 125 families (N = 720) for two variables: 1) apnea hypopnea index (AHI) log transformed and adjusted for age, and 2) AHI log transformed and adjusted for age and body mass index (BMI). We allowed for residual familial correlations and sex-specific means in all models. Analysis of the Caucasian sample showed transmission patterns consistent with that of a major gene that were stronger in the age-adjusted variable than in the age- and BMI-adjusted variable. However, in the African American families, adjusting for BMI in addition to age gave stronger evidence for segregation of a codominant gene with an allele frequency of 0.14, accounting for 35% of the total variance. These results provide support for an underlying genetic basis for OSA that in African Americans is independent of the contribution of BMI.

Long-term follow-up of sleep disordered breathing in older adults

OBJECTIVE

The current study was designed to determine whether, with increasing age, sleep apnea improves, becomes worse, or stays the same.

BACKGROUND

There is a high prevalence of sleep disordered breathing (SDB) in older adults, but little is known about longitudinal changes. This study followed older adults to examine the natural history of SDB.

METHODS

Subjects were randomly selected community-dwelling elderly (n=427). A subset of subjects was studied approximately every 2 years over an 18-year period. Overnight sleep recordings and sleep questionnaires were completed at each time point.

RESULTS

Multiple linear regression showed that three variables were associated with change in respiratory disturbance index (RDI):body mass index (BMI) at initial visit (P=0.001), change in BMI (P=0.02), and a consistent self-report of high blood pressure (P=0.005). RDI increase was associated with BMI increase and presence of self-reported high blood pressure.

CONCLUSIONS

The changes in RDI that occurred were associated only with changes in BMI and were independent of age. This underscores the importance of managing weight for older adults, particularly those with hypertension.

Age-related changes in upper airway muscles morphological and oxidative properties

Obstructive sleep apnea (OSA) is a common disorder of the middle aged and elderly. It results from the decrease in upper airway muscle (UAM) tone that occurs during sleep. It is unclear whether age-related changes in UAM could constitute a contributory mechanism to the increased prevalence of OSA with increasing age, and previous papers evaluating the effects of aging on UAM in rats reported conflicting results. In the present study, we compared, in four age groups of Wistar rats (6-24 months), fiber-type distribution, mean cross-sectional fiber area and succinate dehydrogenase optical density of dilating and non-dilating UAM, and the diaphragm. Succinate dehydrogenase optical density, a marker of oxidative capacity, decreased significantly after the age of 6 months in all muscles (except for the sternohyoid), particularly in the genioglossus, the main tongue protrudor. In this muscle, we also found a significant decrease in type IIa and an increase in IIb fibers after the age of 18 months. Age-related changes in fiber-type distribution in other muscles were mostly insignificant. Dilating UAM could not be distinguished from their non-dilating neighboring muscles by their histochemical properties or aging-related changes. The aging-related changes observed in the present study may decrease UAM endurance, particularly that of the main tongue protrudor, the genioglossus.

Sleep disorders in the elderly

Sleep disorders and sleeping difficulty are among the most pervasive and poorly-addressed problems of aging. As the population ages, a burgeoning cadre of seniors will seek attention for sleeping difficulties and sleep disorders. Sleep changes with age, and sleeping problems and disorders generally increase with aging. At present, health care professionals are not receiving adequate preparation and training to help the elderly cope with age-related sleeping problems, and several specific areas are ripe for investigation.

A comparison of sleep profiles in patients with dementia with lewy bodies and Alzheimer's disease

INTRODUCTION

Sleep disturbances are common in healthy old age and in dementia syndromes. Polysomnography has demonstrated typical changes in both Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) with AD being characterised by sundowning and sleep apnoea and DLB patients showing more disturbances of movement control during sleep. The technical difficulties associated with EEG sleep recordings mean that polysomnography is not possible out of specialist centres.

OBJECTIVES

To use questionnaires to assess the frequency of sleep disturbances in patients with Alzheimer's disease and dementia with Lewy bodies.

METHOD

The sleep profiles of twenty patients with AD and 17 with DLB were assessed using three questionnaires, one designed to assess night time sleep disturbance, one day time sleepiness and the last carer burden. The sleep questionnaires were repeated in a subgroup after treatment with a cholinesterase inhibitor (rivastigmine).

RESULTS

Level of sleep disturbance in both groups was high. DLB patients had more overall sleep disturbance, more movement disorders whilst asleep and more abnormal day time sleepiness. Treatment with rivastigmine produced a trend towards normalisation of sleep profile in a small number of subjects.

CONCLUSIONS

Both groups have extensive sleep problems. The DLB and AD groups have different sleep profiles that are of diagnostic importance and may suggest different treatment strategies. The results are consistent with those found from polysomnographic assessment and suggest that the questionnaires used are sensitive to detect differences previously documented with polysomnography.

CLINICAL REVIEW ARTICLE: Epidemiology of sleep-related obstructive breathing

The diagnosis of obstructive sleep apnoea syndrome (OSAS) and upper airway resistance syndrome (UARS) is based both on a combination of laboratory findings from whole-night sleep recordings and daytime symptoms. Due to the recent interest in breathing disturbances during sleep many prevalence studies have been performed within this field. There are, however, methodological difficulties in characterizing these syndromes in large populations; many of the studies have therefore been unable to present an overview of the complete syndromes but rather have focused on specific characteristics. In epidemiological research snoring and/or daytime sleepiness have often been used as markers of OSAS, while other studies have looked only on the respiratory disturbances or oxygen desaturation. Studies on the prevalence of OSAS based on polysomnography are reviewed here, as well as investigations where associated factors such as cardiovascular diseases and mortality were analysed. The interrelationships between snoring, daytime symptoms and laboratory findings are discussed. Gender, age, obesity, smoking, alcohol and ethnicity are all factors that influence the prevalence of OSAS. The data on associations between OSAS and cardiovascular disease or mortality are sometimes unrelated. Much of the discrepancy between different studies can be explained by the methodological difficulties connected with the definition of OSAS and also by the fact that the association between sleep-disordered breathing and cardiovascular outcome seems to be age-dependent.

Evolution of sleep apnea syndrome in sleepy snorers: a population-based prospective study

This study followed a small number of men previously studied polysomnographically 10 yr earlier to investigate the relationship between the development of sleep-disordered breathing and age, weight gain, and smoking. In 1984, 3,201 men answered a questionnaire including questions about snoring and excessive daytime sleepiness (EDS). Of those reporting symptoms related to obstructive sleep apnea syndrome (OSAS), a random sample of 61 men was investigated using whole-night polysomnography in 1985. Ten years later, 38 men participated in the present follow-up, which included a structured interview and polysomnography. During the 10-yr period, nine men had been treated for OSAS. Of the 29 untreated subjects, the number of men with OSAS, defined as an apnea-hypopnea index (AHI) of >/= 5/h, increased from four in 1985 to 13 in 1995 (p < 0.01). In this small sample, no significant associations were found between DeltaAHI (i.e., AHI 1995 - AHI 1985) and age, weight gain, or smoking. We conclude that, among this small group of individuals who were selected for original polysomnographic study and follow-up because they were thought to have symptoms of sleep apnea, sleep-disordered breathing became significantly worse over time.

Recognition and consequences of obstructive sleep apnea hypopnea syndrome

There is a growing recognition of sleep-disordered breathing (SDB) in patient groups and in the general population. This article reviews issues related to recognizing the disorder, including the problems of relying on narrowly defined polysomnographic data for case findings and for assessment of disease severity. The distributions of symptoms and physiologic measurements of SDB in the population and their inter-relationships are reviewed. The epidemiological data that address risk factors and consequences of sleep apnea hypopnea syndrome (SAHS) also are discussed, with recommendations regarding recognition priorities.

Comparison of the severity of sleep-disordered breathing in Asian and Caucasian patients seen at a sleep disorders center

Race can be considered a risk factor for sleep-disordered breathing (SDB), with higher prevalences and greater severity of the disorder documented among persons of certain racial groups compared with others. Based on clinical observation, it was hypothesized that, other risk factors being equal, Asian patients with SDB have greater severity of their illness compared to Caucasian patients. A cross-sectional study was conducted at a sleep disorders clinic involving 105 Asian patients diagnosed as having SDB after undergoing polysomnography and 99 similarly diagnosed Caucasian patients matched for the following variables: age, gender and body mass index (BMI). The main outcome measure of interest was objective assessment of severity based on polysomnographic data of respiratory disturbance index (RDI) and minimum oxygen saturation (SaO2) during sleep. Symptom scores between patients of the two racial groups were also compared. There were significantly larger proportions of Asians compared to Caucasians with severe obstructive sleep apnea (OSAS) as defined by respiratory disturbance index (RDI) > or = 50 (25.0% vs 11.1%; P = 0.0288) or minimum oxygen saturation (SaO2) < or = 69% (20.6% vs 4.2%; P = 0.0113). The mean minimum SaO2 was significantly lower (P = 0.0001) while the mean (log transformed) esophageal pressure (Pes) value was significantly higher (P = 0.0090) in the Asian group. Logistic regression analysis showed that race was associated with severe SDB (RDI > or = 50) independent of age, sex and BMI. The estimated odds ratio for Asians having severe OSAS compared with Caucasians was 2.51 [95% Confidence Interval (CI) 0.98-6.64]. There was no significant difference in the severity of questionnaire-based symptoms of snoring, apneas during sleep and the median Epworth scores between Asian and Caucasian patients. Based on objective polysomnographic results, Asian patients with OSAS have greater severity of their illness compared to Caucasian patients matched for age, gender and BMI. There was, however, no significant difference in severity of questionnaire-based symptoms between Asian and Caucasian patients with SDB.

Reproducibility of oximetry with a static charge-sensitive bed in evaluation of obstructive sleep apnoea

The reproducibility of overnight polygraphic recording with oximetry, the use of a static charge-sensitive bed (SCSB), thermistors and a body position sensor was assessed in diagnosing obstructive sleep apnoea syndrome (OSAS). Forty-six patients with a clinical suspicion of OSAS underwent a repeat recording. No treatment for OSAS and no change in patient characteristics was allowed between duplicate nights. Between repeated recordings significant correlations were found for ODI4, time spent at SaO2 < 90% and the mean nadir SaO2. Good agreement was found in concordance of classification of ODI4, time spent at SaO2 < 90% and body movements. The combination of oximetry, thermistors, SCSB and body position sensor has a good reproducibility as an affordable screening method in the evaluation of OSAS.

Recognition and consequences of obstructive sleep apnea hypopnea syndrome

There is a growing recognition of sleep-disordered breathing (SDB) in patient groups and in the general population. This article reviews issues related to recognizing the disorder, including the problems of relying on narrowly defined polysomnographic data for case findings and for assessment of disease severity. The distributions of symptoms and physiologic measurements of SDB in the population and their inter-relationships are reviewed. The epidemiological data that address risk factors and consequences of sleep apnea hypopnea syndrome (SAHS) also are discussed, with recommendations regarding recognition priorities.