A comparison of men and women with occlusive sleep apnea syndrome

Sleep disturbances based on patient reported outcomes in patients with breast cancer

PURPOSE

Sleep disturbances are common in patients with breast cancer, but comprehensive evaluations with patient-reported outcomes (PRO) and sleep evaluation with polysomnography (PSG) are lacking. This study describes sleep disruption using PROs and PSG to identify underlying sleep disorders.

METHODS

A retrospective review of patients with breast cancer undergoing formal sleep evaluation from 4/1/2009 to 7/31/2014 was performed. Clinical characteristics, PROs using Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS), and PSG data were reviewed.

RESULTS

404 patients were identified with 43% early, 30% locally advanced and 17% metastatic disease. PSQI revealed poor sleep in 75%, and ESS demonstrated daytime sleepiness in 55%. Sleep aid use was reported by 39%, and pain medication use in 22%. Most patients (50.2%) had multiple sleep disorders. Insomnia (54.5%) was the most frequent sleep disorder, followed closely by obstructive sleep apnea (OSA) (53.7%). PSG was performed in 74%. Multivariate analysis linked poor sleep to use of sleep aids [OR 7.7, 95% CI 3.9 to 15.2], anxiety disorder [OR 4.8, 95% CI 1.7 to 14.0], and metastatic disease [OR 2.8, 95% CI 1.1 to 6.6]. Daytime sleepiness correlated with known diagnosis of OSA [OR 1.9, 95% CI 1.0 to 3.3] and sleep aid use [OR 0.6, 95% CI 0.4 to 0.9].

CONCLUSIONS

Poor sleep was associated with sleep aid use, anxiety disorder and metastatic disease. Insomnia was the most common sleep disorder, followed by OSA (mostly mild). Education about sleep health and proactive screening for sleep symptoms would be beneficial in patients with breast cancer.

Sleep disturbance in rodent models and its sex-specific implications

Sleep disturbances, encompassing altered sleep physiology or disorders like insomnia and sleep apnea, profoundly impact physiological functions and elevate disease risk. Despite extensive research, the underlying mechanisms and sex-specific differences in sleep disorders remain elusive. While polysomnography serves as a cornerstone for human sleep studies, animal models provide invaluable insights into sleep mechanisms. However, the availability of animal models of sleep disorders is limited, with each model often representing a specific sleep issue or mechanism. Therefore, selecting appropriate animal models for sleep research is critical. Given the significant sex differences in sleep patterns and disorders, incorporating both male and female subjects in studies is essential for uncovering sex-specific mechanisms with clinical relevance. This review provides a comprehensive overview of various rodent models of sleep disturbance, including sleep deprivation, sleep fragmentation, and circadian rhythm dysfunction. We evaluate the advantages and disadvantages of each model and discuss sex differences in sleep and sleep disorders, along with potential mechanisms. We aim to advance our understanding of sleep disorders and facilitate sex-specific interventions.

Sex differences in sleep and sleep-disordered breathing

PURPOSE OF REVIEW

There is increasing evidence for relevant sex differences in pathophysiology, symptom presentation and outcomes in obstructive sleep apnoea (OSA). However, research on sex differences and sex-specific phenotypes in sleep-disordered breathing (SDB) is still in its infancy and data on sex differences in other SDB is still very scarce.

RECENT FINDINGS

While OSA is more common in men than in premenopausal women, the prevalence of OSA doubles postmenopausally and becomes comparable to that of men. Women have a lower collapsibility of the upper airway and a lower arousal threshold. In addition, the rapid eye movement (REM)-apnoea-hypopnoea index (AHI) is typically higher in women than in men, but the non-REM-AHI and thus the total AHI is often lower. Women are often symptomatic at lower AHI and present more frequently with symptoms of sleep fragmentation and poor sleep quality. Both certain forms of OSA (e.g. REM-OSA) and certain phenotypes (e.g. COMISA) are more common in women. Men have a higher risk of high loop gain central sleep apnoea.

SUMMARY

For a better understanding of sex-typical phenotypes with the aim of a more targeted treatment approach of SDB, adequately powered studies on sex differences in SDB should be conducted.

Reaction time in psychomotor vigilance task is related to hypoxic load in males with sleep apnea

Oxygen saturation (SpO2 )-based parameters are more strongly linked to impaired daytime vigilance than the conventional diagnostic metrics in patients with obstructive sleep apnea (OSA). However, whether the association between SpO2 -based parameters and impaired daytime vigilance is modulated by sex, remains unknown. Hence, we investigated the interplay between sex and detailed SpO2 -based metrics and their association with impaired vigilance in patients with OSA. The study population consisted of 855 (473 males, 382 females) patients with suspected OSA who underwent overnight polysomnography and psychomotor vigilance task (PVT). The population was grouped by sex and divided into quartiles (Q1-Q4) based on median reaction times (RTs) in the PVT. In addition to conventional diagnostic metrics, desaturation severity (DesSev), fall severity (FallSev), and recovery severity (RecovSev) were compared between the sexes and between the best (Q1) and worst (Q4) performing quartiles by using cumulative distribution functions (CDFs). Additionally, sex-specific covariate-adjusted linear regression models were used to investigate the connection between the parameters and RTs. The CDFs showed significantly higher hypoxic load in Q4 in males compared to females. In addition, the DesSev (β = 8.05, p < 0.01), FallSev (β = 6.48, p = 0.02), RecovSev (β = 9.13, p < 0.01), and Oxygen Desaturation Index (β = 12.29, p < 0.01) were associated with increased RTs only in males. Conversely, the Arousal Index (β = 10.75-11.04, p < 0.01) was associated with impaired vigilance in females. The severity of intermittent hypoxaemia was strongly associated with longer RTs in males whereas the Arousal Index had the strongest association in females. Thus, the impact of hypoxic load on impaired vigilance seems to be stronger in males than females.

Obstructive Sleep Apnea and Stroke: Determining the Mechanisms Behind their Association and Treatment Options

Sleep-disordered breathing (SDB) can be a sequela of stroke caused by vascular injury to vital respiratory centers, cerebral edema, and increased intracranial pressure of space-occupying lesions. Likewise, obstructive sleep apnea (OSA) contributes to increased stroke risk through local mechanisms such as impaired ischemic cerebrovascular response and systemic effects such as promoting atherosclerosis, hypercoagulability, cardiac arrhythmias, vascular-endothelial dysfunction, and metabolic syndrome. The impact of OSA on stroke outcomes has been established, yet it receives less attention in national guidelines on stroke management than hyperglycemia and blood pressure dysregulation. Furthermore, whether untreated OSA worsens stroke outcomes is not well-described in the literature. This scoping review provides an updated investigation of the correlation between OSA and stroke, including inter-relational pathophysiology. This review also highlights the importance of OSA treatment and its role in stroke outcomes. Knowledge of pathophysiology, the inter-relationship between these common disorders, and the impact of OSA therapy on outcomes affect the clinical management of patients with acute ischemic stroke. In addition, understanding the relationship between stroke outcomes and pre-existing OSA will allow clinicians to predict outcomes while treating acute stroke.

Sex-specific differences in presenting symptoms of obstructive sleep apnea

OBJECTIVES

Scant data from India are available on the gender differences in presenting features of Obstructive Sleep Apnea (OSA) in India. This study aims to compare male and female patients with OSA for general characteristics and presenting symptoms.

METHODOLOGY

Retrospective study was done in OSA patients diagnosed in our sleep lab. History, biochemical reports, and polysomnography variables were retrieved from the sleep registry and were compared between males and females.

RESULTS

Out of 514 patients of OSA (367 males; 147 females). Females were older (55.97 ± 9.73 v/s 50.2 + 12.70 years, P<0.001) and more obese (BMI 35.26 ± 7.17 v/s 29.58 ± 5.49 Kg/m2; P<0.001). Waist and hip circumference were significantly higher in the female patients (P = 0.009 and <0.001 respectively). Morning headache, nocturia, fatigability (P < 0.001), and depression (P = 0.005) was more common in females (P = 0.036). Hypersomnia was more commonly seen in males (P < 0.001). Mean diastolic blood pressure was significantly higher in males, although no difference was seen in Systolic BP. Females had higher mean Fasting Blood glucose (FBS) (P = 0.02). Apnea hypopnea index was significantly higher in females {P = 0.01}.

CONCLUSION

Women with OSA are more obese, elderly, and with higher fasting blood glucose than males at the time of diagnosis. Females have a higher prevalence of symptoms like fatigability, depression, nocturia and early morning headache and had more severe AHI than males.

Duration of respiratory events in obstructive sleep apnea: Factors influencing the duration of respiratory events

Several factors influence respiratory event duration during sleep. In general, women have shorter respiratory events compared to men as it appears that women have a more reactive upper airway contributing to the occurrence of short events. In addition, the increased amount of adipose tissue in the upper airways should make the reopening of the upper airways more difficult, leading to long respiratory events. Nevertheless, an increase in body mass index decreases the median duration of apneas, hypopneas, and desaturations in all OSA severity categories. Also, respiratory events are longer in older adults compared to younger ones, and the most likely mechanism explaining this phenomenon appears to be the increased circulatory delay associated with aging. Several studies have also shown that apnea events are longer in rapid eye movement sleep compared to non-rapid eye movement sleep. The main mechanism behind these differences appears to be the greater pharyngeal muscle relaxation during rapid eye movement sleep. Finally, sleeping position affects the duration of respiratory events; apneas and hypopneas are longer in the supine compared to lateral postures regardless of the severity of OSA. In the present report, we discuss the best-known factors influencing the duration of abnormal breathing events during sleep.

Accuracy and modification of the STOP ‐bang questionnaire for screening patients with obstructive sleep apnea in China

Despite the high sensitivity of the STOP-Bang questionnaire [snoring, tiredness, observed apneas, high blood pressure, body mass index, age, neck size, gender] questionnaire (SBQ), which is widely used to screen individuals at high risk of obstructive sleep apnea (OSA), few studies have evaluated the discrimination related to sex in the SBQ. Therefore, our study aimed to assess whether SBQ performance is gender-related and modified by changing body mass index (BMI) and neck circumference (NC) cut-off values. A total of 470 patients attended the sleep centres. They were divided into moderate-to-severe OSA and non-moderate-to-severe OSA groups based on the apnea-hypopnea index (AHI) and the results of the SBQ screening. The predictive performance of the SBQ screening instrument was evaluated by 2 × 2 contingency tables and discriminatory ability, which was estimated from the area under the curve (AUC) obtained from receiver operating characteristic curve. Our results suggest that when screening for moderate-to-severe OSA, the original SBQ has higher sensitivity and lower specificity for men; however, women have higher specificity and lower sensitivity. The SBQ achieved the maximum AUC of 0.783 for men and 0.634 for women when the BMI cut-off value was established at 30 kg/m² and the NC cut-off value was established at 38 cm in men, and the BMI cut-off value was established at 25 kg/m² and the NC cut-off value at 36 cm in women. Balancing the optimal sensitivity and specificity, the cut-off value of the optimal modified SBQ total scores for men was determined to be ≥4 and ≥3 for women.

Sea level nocturnal minimal oxygen saturation can accurately detect the presence of obstructive sleep apnea in a population with high pretest probability

PURPOSE

To evaluate whether a predictive model based on nocturnal minimal oxygen saturation (SpO₂) alone can accurately detect the presence of obstructive sleep apnea (OSA) in a population with suspected OSA.

METHODS

A total of 4297 participants with suspected OSA were enrolled in this study, and laboratory-based polysomnography (PSG) tests were performed at sea level in all subjects. Nocturnal minimal SpO₂ was obtained automatically as part of the PSG test. Stratified sampling was used to divide the participants' data into the training set (75%) and the test set (25%). An OSA detection model based on minimal SpO₂ alone was created using the training set data and its performance was evaluated using the independent test set data ("hold-out" evaluation). Gender-specific models, and models based on minimal SpO₂ in combination with other predictive factors (age, body mass index, waist-to-hip ratio, snoring grade, Epworth Sleepiness Scale score, and comorbidities), were also created and compared in terms of OSA detection performance.

RESULTS

The prevalence of OSA was 85.6% in our study population. The models including multiple predictors, and the gender-specific models, failed to outperform the model based solely on minimal SpO₂, which showed good predictive performance (C statistic, 0.922) having an overall accuracy rate of 0.86, sensitivity of 0.87, specificity of 0.84, positive predictive value of 0.97, and positive likelihood ratio of 5.34. In addition, the model based on minimal SpO₂ alone could also accurately predict the presence of moderate-to-severe OSA and severe OSA, with C statistics of 0.914 and 0.900, respectively.

CONCLUSIONS

A predictive model based on nocturnal minimal SpO₂ alone may be an alternative option to detect the presence of OSA in a high-risk population when standard diagnostic tests are unavailable.

Impact of Gender and Age on Rapid Eye Movement-Related Obstructive Sleep Apnea: A Clinical Study of 3234 Japanese OSA Patients

Rapid eye movement (REM)-related obstructive sleep apnea (OSA) is characterized by apnea and hypopnea events due to airway collapse occurring predominantly or exclusively during REM sleep. Previous studies have reported that REM-related OSA occurs more commonly in women and younger individuals. However, external validity of this tendency has not been confirmed in a large clinical sample. The objective of this study was to evaluate the effect of gender and age on REM-related OSA after adjustment for several covariates based on their established clinical relationships to gender difference in OSA. A total of 3234 Japanese patients with OSA were enrolled in this study. We confirmed that female sex is an important risk factor for REM-related OSA, as reported by previous studies. Moreover, we showed that women aged over 50 years were at a greater risk than those aged under 50 years. These results suggest that hormonal changes in women might play an important role in REM-related OSA and might reflect its unknown pathophysiological characteristics.

Gender differences in severity of desaturation events following hypopnea and obstructive apnea events in adults during sleep

OBJECTIVE

Severity estimation of obstructive sleep apnea (OSA) is currently based on the apnea-hypopnea index (AHI), which ignores individual breathing cessation event characteristics. Gender differences in the relationship between the breathing cessation event duration and the related desaturation event severity could mean that the severity of OSA is different in males and females despite a similar AHI. The aim of this work was to evaluate gender differences in the severity of peripheral oxygen desaturation events following obstructive apneas or hypopneas.

APPROACH

Type I polysomnographic recordings of 220 males and 175 females were analyzed. The obstructive apnea and hypopnea events were divided into eight different durational categories from 10 s to 45 s with 5 s interval and  >45 s. The desaturation event severities following obstructive apneas or hypopneas were compared between genders within these durational categories.

MAIN RESULTS

Desaturations following obstructive apneas with a duration of 30-45 s were substantially more severe (p  <  0.05) in females compared to males. In contrast, areas of desaturations following hypopneas (with related hypopnea event durations  ⩽30 s) were smaller (p  <  0.05) in females compared to males. In general, desaturation events following obstructive apneas were more severe compared to desaturations following hypopneas and the increase in the duration of obstructive apnea and hypopnea events led to an increase in the related desaturation severity in both genders.

SIGNIFICANCE

We found gender differences in the desaturation event severities following obstructive apneas and hypopneas. The results indicate that in females longer obstructive apneas (>30 s) could be more detrimental compared to those of males. As severe health consequences are related to the desaturation severity these aspects should be considered when estimating the severity of OSA.

Obstructive Sleep Apnea in Women: Specific Issues and Interventions

Obstructive sleep apnea (OSA) has traditionally been seen as a male disease. However, the importance of OSA in women is increasingly being recognized, along with a number of significant gender-related differences in the symptoms, diagnosis, consequences, and treatment of OSA. Women tend to have less severe OSA than males, with a lower apnea-hypopnea index (AHI) and shorter apneas and hypopneas. Episodes of upper airway resistance that do not meet the criteria for apneas are more common in women. Prevalence rates are lower in women, and proportionally fewer women receive a correct diagnosis. Research has also documented sex differences in the upper airway, fat distribution, and respiratory stability in OSA. Hormones are implicated in some gender-related variations, with differences between men and women in the prevalence of OSA decreasing as age increases. The limited data available suggest that although the prevalence and severity of OSA may be lower in women than in men, the consequences of the disease are at least the same, if not worse for comparable degrees of severity. Few studies have investigated gender differences in the effects of OSA treatment. However, given the differences in physiology and presentation, it is possible that personalized therapy may provide more optimal care.

Study of a Novel APAP Algorithm for the Treatment of Obstructive Sleep Apnea in Women

STUDY OBJECTIVES

To assess the efficacy of a novel female-specific autotitrating continuous positive airway pressure (CPAP) algorithm (AutoSet for her, AfH) in premenopausal women relative to a standard autotitrating algorithm (AutoSet, S9) (ResMed Ltd., Bella Vista, New South Wales, Australia).

DESIGN

Prospective randomised crossover noninferiority trial.

SETTING

Tertiary hospital sleep clinic and university research sleep laboratory.

PARTICIPANTS

20 female patients with obstructive sleep apnea (OSA) established on long-term CPAP treatment.

INTERVENTIONS

Treatment with 1 night each of AfH and AutoSet while monitored with overnight laboratory-based polysomnography (PSG); order randomly allocated.

MEASUREMENTS AND RESULTS

The primary outcome variables were the apnea-hypopnea index (AHI) and 3% oxygen desaturation index (ODI 3%) determined from PSG. Treatment efficacy on the AfH night was noninferior to the AutoSet night as assessed by median (IQR) AHI (1.2 [0.60-1.85]/h versus 1.15 [0.40-2.85]/h, respectively, P = 0.51) and 3% ODI (0.85 [0.25-1.5]/h versus 0.5 [0.25-2.55]/h, respectively, P = 0.83). Other PSG measures were similar, except for the percentage of the night spent in flow limitation, which was lower on the AfH (0.14%) than the AutoSet night (0.19%, P = 0.007). The device-downloaded 95th centile pressure on the AfH night was also lower than on the AutoSet night (10.6 ± 1.7 versus 11.6 ± 2.6 cmH2O, respectively; mean difference [95% confidence interval]: -1.1 [-2.13 to -0.01] cm H2O).

CONCLUSION

Among premenopausal women a novel female-specific autotitrating algorithm (AfH) is as effective as the standard AutoSet algorithm in controlling obstructive sleep apnea (OSA). The new algorithm may reduce flow limitation more than the standard algorithm and achieve control of OSA at a lower (95th centile) pressure.

Effect of prone positioning in mild to moderate obstructive sleep apnea syndrome

BACKGROUND

Sleeping in prone position could be effective in the management of obstructive sleep apnea (OSA) syndrome by reducing the gravity effect on the upper airway and hence collapsibility. Effect of pure prone positioning (PPP) treatment was investigated in mild to moderate OSA.

PATIENTS AND METHODS

Twenty-nine mild to moderate OSA patients (17 males, 12 females) who gave informed consent were tested with polysomnography at diagnostic and PPP nights. PPP device consisted of a pillow mounted on a table with a hole in the middle keeping the neck 180° extended in prone position. Mean ± SD of age and AHI were 48.4 ± 10.6 and 15.5 ± 6.2, respectively. Patients did not have abdominal and/or truncalobesity, or any condition that could interfere with prone sleeping.

RESULTS

AHI (mean difference: PPP treatment - diagnostic night: -5.2/h, 95% confidence interval [CI]: -0.1/h to -10.3/h, p = 0.04) and sleep oxygen saturation below 90% (mean difference: -1.80%, 95% CI: -0.22% to -3.37%, p = 0.02) and sleep efficiency (81.0 ± 21.2% and 88.1 ± 7.1 %, respectively, p = 0.02) were significantly lower in PPP than diagnostic night. Response to PPP treatment defined as AHI <5/h in the PPP night was observed in 15 (51.7%) patients, with a better rate in female than male patients (9/12 vs. 6/17, respectively, p = 0.03).

CONCLUSIONS

To our knowledge, this is the first study to examine the effect of prone positioning in the treatment of mild to moderate OSA. Application of PPP with a more comfortable design in a randomized clinical trial is required to investigate its long term effect in the treatment of mild to moderate OSA.

[Obstructive sleep apnea in women]

The prevalence of sleep disturbances and their symptomatic manifestations may be different in men and women. Women with obstructive sleep apnea are less likely to be diagnosed with sleep apnea compared to men, probably due to atypical symptoms such as morning headaches, symptoms of depression and daytime fatigue. There is a great importance of diagnosis and treatment of sleep disorders regarding quality of life, co-morbidity and mortality in both genders.

Medication effects on sleep and breathing

Sleep respiration is regulated by circadian, endocrine, mechanical and chemical factors, and characterized by diminished ventilatory drive and changes in Pao2 and Paco2 thresholds. Hypoxemia and hypercapnia are more pronounced during rapid eye movement. Breathing is influenced by sleep stage and airway muscle tone. Patient factors include medical comorbidities and body habitus. Medications partially improve obstructive sleep apnea and stabilize periodic breathing at altitude. Potential adverse consequences of medications include precipitation or worsening of disorders. Risk factors for adverse medication effects include aging, medical disorders, and use of multiple medications that affect respiration.

Sleep disorders in morbid obesity

The increasing prevalence of obesity has lead to an increase in the prevalence of sleep disordered breathing in the general population. The disproportionate structural characteristics of the pharyngeal airway and the diminished neural regulation of the pharyngeal dilating muscles during sleep predispose the obese patients to pharyngeal airway collapsibility. A subgroup of obese apneic patients is unable to compensate for the added load of obesity on the respiratory system, with resultant daytime hypercapnia. Weight loss using dietary modification and life style changes is the safest approach to reducing the severity of sleep apnea, but its efficacy is limited on the long run. Although it has inherent risks, bariatric surgery provides the most immediate result in alleviating sleep apnea. Obesity has been linked also to narcolepsy. The loss of neuropeptides co-localized in hypocretin neurons is suggested as the potential mechanism. Poor sleep quality, which leads to overall sleep loss and excessive daytime sleepiness has also become a frequent complaint in this population. Identifying abnormal nocturnal eating is critically important for patient care. Both sleep related eating disorder and night eating syndrome are treatable and represent potentially reversible forms of obesity.

Epidemiology, pathophysiology, and clinical features of obstructive sleep apnea

The normal cycle of respiration includes a unique balancing force between many upper airway structures that control its dilation and closure. Alteration of this delicate equilibrium, possibly by an increased airflow resistance, can cause various degrees of obstructive sleep apnea (OSA). OSA is now recognized as a major illness, an important cause of medical morbidity and mortality affecting millions of people worldwide, and a major predisposing factor for several systemic conditions, such as hypertension, cardiovascular disease, stroke, diabetes, and even sexual dysfunction. Initial evaluation for possible OSA may be done by dental professionals who can provide guidance for its comprehensive evaluation and management. Because of the complexity of the disease, factors contributing to its development must be identified. Some factors caused by the patient's anatomic structures are slightly easier to rectify, whereas others may relate to the patient's age, sex, habits, or associated illnesses, including obesity. In this article, various epidemiologic, pathophysiologic, and clinical features of OSA are discussed.

Sleep disorders and medical conditions in women. Proceedings of the Women & Sleep Workshop, National Sleep Foundation, Washington, DC, March 5-6, 2007

Sleep disorders affect women differently than they affect men and may have different manifestations and prevalences. With regard to obstructive sleep apnea (OSA), variations in symptoms may cause misdiagnoses and delay of appropriate treatment. The prevalence of OSA appears to increase markedly after the time of menopause. Although OSA as defined by the numbers of apneas/hypopneas may be less severe in women, its consequences are similar and perhaps worse. Therapeutic issues related to gender should be factored into the management of OSA. The prevalence of insomnia is significantly greater in women than in men throughout most of the life span. The ratio of insomnia in women to men is approximately 1.4:1.0, but the difference is minimal before puberty and increases steadily with age. Although much of the higher prevalence of insomnia in women may be attributable to the hormonal or psychological changes associated with major life transitions, some of the gender differences may result from the higher prevalence of depression and pain in women. Insomnia's negative impact on quality of life is important to address in women, given the high relative prevalence of insomnia as well as the comorbid disorders in this population. Gender differences in etiology and symptom manifestation in narcolepsy remain understudied in humans. There is little available scientific information to evaluate the clinical significance and specific consequences of the diagnosis of narcolepsy in women. Restless legs syndrome (RLS) is characterized by an urge to move the legs or other limbs during periods of rest or inactivity and may affect as much as 10% of the population. This condition is more likely to afflict women than men, and its risk is increased by pregnancy. Although RLS is associated with impaired quality of life, highly effective treatment is available.

[The role of family physicians in the recognition and screening of obstructive sleep apnea]

Obstructive sleep apnea is the most frequent sleep disorder. The prevalence of sleep apnea in the general population is 2-4% and the main characteristic of the disease is the intermittent cessation or substantial reduction of airflow during sleep, caused by complete, or near complete upper airway obstruction. Decreased airflow is followed by oxygen desaturation and intermittent arousals. The clinical presentation of the disorder is complex. Loud snoring with breathing pauses and daytime sleepiness should raise the suspicion of sleep apnea, but we have to consider this disease if the patient has therapy resistant hypertension, heart failure, arrhythmias, stroke, depression or memory problems. Family physicians have an important role in recognizing sleep apnea. High risk patients can easily be identified by the main symptoms and using the Berlin sleep apnea questionnaire. These patients should be referred to a sleep laboratory for polysomnographic assessment and, if necessary, for further treatment.

Gender differences in obstructive sleep apnea and treatment implications

Obstructive sleep apnea (OSA) is a common cause of daytime sleepiness for millions of Americans. It is also a disease associated with an increased likelihood of hypertension, cardiovascular disease, stroke, daytime sleepiness, motor vehicle accidents, and diminished quality of life. A number of population-based studies have shown that OSA is more common in men than in women and this discrepancy is often evident in the clinical setting. There are a number of pathophysiological differences to suggest why men are more prone to the disease than women. Although the exact mechanisms are unknown, differences in obesity, upper airway anatomy, breathing control, hormones, and aging are all thought to play a role. The purpose of this review was to examine the literature on gender differences in OSA and to analyze whether or not these differences in pathogenic mechanisms affect diagnosis or treatment.

Obstructive Sleep Apnoea in Singapore: Polysomnography Data From a Tertiary Sleep Disorders Unit

Introduction: Comprehensive sleep architecture and respiratory event data in local patients with suspected obstructive sleep apnoea (OSA) from overnight polysomnography (PSG), the gold standard for the evaluation of sleep-related breathing disorders, are not widely available. We present 1 year retrospective PSG data with the objective of describing PSG characteristics of patients evaluated for OSA in Singapore. Materials and Methods: PSG data of patients evaluated for OSA in 1 year (January through December 2005) in the Sleep Laboratory of a public tertiary hospital were retrospectively reviewed. Results: Five hundred and eighty-four diagnostic PSG studies were performed in patients with symptoms suggestive of sleep-disordered breathing, including snoring, excessive daytime sleepiness, unrefreshing sleep, or recurrent unexplained awakenings. There were 449 male patients (76.9%) and 135 female patients (23.1%), with a mean age of 47.5 years (SD 12.7). Men were on average younger than women, 46.1 years versus 52.0 years (P <0.0005). The mean body mass index (BMI) was 27.9 (SD 6.7), with no significant difference between genders. An association was shown between apnoea-hypopnoea index (AHI) and BMI (Pearson correlation index r = 0.362). Men had overall significantly higher AHI (16.5 vs 9), shorter mean sleep onset latency (11 vs 16.5 minutes), more light sleep (65.5% vs 58.9%), less deep sleep (17.7% vs 23%), and more respiratory event related arousals per hour of sleep (11.6 vs 5.1) (P <0.0005). Severity was classified: AHI <5 (“Normal Overall AHI”) (28.3%), AHI 5-15 (“Mild”) (22.3%), AHI >15-30 (“Moderate”) (18.3%), AHI >30 (“Severe”) (31.2%). There was no significant age difference among the 4 groups. More severe OSA patients were significantly heavier, and had more light sleep, less deep sleep, less REM sleep, more respiratory event related arousals and lower levels of oxygen desaturation. Conclusion: OSA is predominant in middle-aged, overweight Singapore males and much less common in females who tend to be older. A majority of patients have moderate to severe OSA, which significantly disturbs normal sleep architecture. The relatively lower BMI compared to Caucasian OSA populations may be related to local craniofacial characteristics and/or higher percentage of body fat for BMI which has been described in Singaporeans. Key words: Body-mass index, Obstructive sleep apnoea (OSA), Polysomnography (PSG), Sleep architecture

Gender differences in Saudi patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) remains under-recognized in women possibly due to differences in clinical presentation, difference in tolerance to symptoms, and rate of usage and referral to sleep services. No reports have addressed OSA in women in the Middle Eastern (Arab) population. Therefore, we conducted this study to assess the differences in demographics, clinical presentation, and polysomnographic (PSG) findings between Saudi women and men diagnosed to have (OSA). The study group comprised 191 consecutive Saudi women and 193 consecutive men who were referred to the Sleep Disorders Centre and were found by in-laboratory PSG to have OSA. Demographic and clinical data were obtained by personal interviews. Women were significantly older than men (53.9 and 43.0 years, respectively; p < 0.001). Similarly, their body mass index was significantly higher than men (p < 0.001). Insomnia was more common among women (39.8%) compared to men (25.9%; p = 0.005). Other sleep symptoms including witnessed apnea, and excessive daytime sleepiness did not show any statistical difference between the two groups. Women were more likely than men to be diagnosed with hypothyroidism, diabetes, hypertension, cardiac disease, and asthma. Apnea-hypopnea index (AHI) was statistically higher in men compared to women; however, most of apnea/hypopnea events in women occurred during rapid eye movement sleep, and the mean duration of hypopnea and apnea was significantly lower in women (p = 0.004). Sleep efficiency was lower in women (71.5% vs. 77.7%) in men (p < 0.001). The desaturation index was higher in men (p = 0.01), but no difference was found in lowest SaO2 or time with SaO2 less than 90%. The present study showed important clinical and PSG differences between Saudi women and men with OSA. Clinicians need to be aware of these differences when assessing women for the possibility of OSA as they may be symptomatic at a lower AHI and have significant comorbid conditions that can be adversely affected if their OSA was not timely managed.

Obesity and obstructive sleep apnea: pathogenic mechanisms and therapeutic approaches

Obstructive sleep apnea is a common disorder whose prevalence is linked to an epidemic of obesity in Western society. Sleep apnea is due to recurrent episodes of upper airway obstruction during sleep that are caused by elevations in upper airway collapsibility during sleep. Collapsibility can be increased by underlying anatomic alterations and/or disturbances in upper airway neuromuscular control, both of which play key roles in the pathogenesis of obstructive sleep apnea. Obesity and particularly central adiposity are potent risk factors for sleep apnea. They can increase pharyngeal collapsibility through mechanical effects on pharyngeal soft tissues and lung volume, and through central nervous system-acting signaling proteins (adipokines) that may affect airway neuromuscular control. Specific molecular signaling pathways encode differences in the distribution and metabolic activity of adipose tissue. These differences can produce alterations in the mechanical and neural control of upper airway collapsibility, which determine sleep apnea susceptibility. Although weight loss reduces upper airway collapsibility during sleep, it is not known whether its effects are mediated primarily by improvement in upper airway mechanical properties or neuromuscular control. A variety of behavioral, pharmacologic, and surgical approaches to weight loss may be of benefit to patients with sleep apnea, through distinct effects on the mass and activity of regional adipose stores. Examining responses to specific weight loss strategies will provide critical insight into mechanisms linking obesity and sleep apnea, and will help to elucidate the humoral and molecular predictors of weight loss responses.

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 disorders in women: clinical evidence and treatment strategies

Sleep disorders are more prevalent in women than in men. Sex hormones modulate sleep-wake behaviors and mood and may contribute to heightened risk across the life cycle of women. Sleep disorders may have a unique expression in women, emerging throughout their reproductive life cycle. These conditions require careful treatment strategy to manage medical, hormonal, and behavioral contributing factors to poor sleep efficiency and impaired quality of life. This review focuses on clinical evidence for sleep disorders in women and discusses existing evidence of risk factors and treatment options for insomnia and sleep-disordered breathing in women.

Gender differences on polysomnographic findings in Greek subjects with obstructive sleep apnea syndrome

BACKGROUND AND PURPOSE

Studies from North American clinics have reported that females with obstructive sleep apnea syndrome (OSAS) are about the same age as males but are heavier, have less severe apnea and make up a much smaller proportion of cases. We examined polysomnographic differences between Greek men and women with OSAS in order to study the influence of gender on clinical presentation and laboratory findings.

PATIENTS AND METHODS

This retrospective study included a cohort of 1,010 Greek patients (844 males, 166 females) diagnosed with OSAS by overnight polysomnography (PSG), who were referred to the Sleep Disorders Center of Evangelismos Hospital, Athens Medical School, University of Athens. All patients were studied over a period of three consecutive years, during which time clinical and polysomnography (PSG) findings were compared.

RESULTS

Body mass index (BMI) was similar in men and women with OSAS (BMI=31.6+/-5.5kg/m(2) in men versus BMI=32.5+/-8.1 (SD) kg/m(2) in women). Female patients were significantly older than male patients (56.9+/-10.6 versus 50.6+/-11.7 year, P=0.001). The mean apnea-hypopnea index (AHI) during total sleep time was higher in men than in women (42.4+/-28.2 versus 33.2+/-27.7 events/h, P<0.001). The AHI in non-rapid eye movement (NREM) sleep was higher in men than in women (42.9+/-28.9 versus 32.6+/-28.7 events/h, P<0.001), but in rapid eye movement (REM) sleep AHI was similar in men and women (36.0+/-23.3 versus 34.9+/-25.4 events/h). Forty percent of men had AHI-REM sleep >AHI-NREM compared to 62% of women, and the difference between REM and NREM-AHI was significantly less in men than in women (14.21+/-11.18 versus 19.76+/-13.43 events/h, P<0.001)). Several aspects of sleep were worse in women versus men: sleep efficiency index was lower (79.4+/-16.1% versus 85.1+/-12.5%, P<0.001); sleep onset latency (27.7+/-27.7 versus 17.9+/-18.1min, P<0.001), and REM onset latency (161.5+/-76.2 versus 145.7+/-71.4min, P<0.018) were longer; wake time after sleep onset (WASO) was also greater in women (42.6+/-46.5 versus 30.7+/-34.9min, P<0.003).

CONCLUSIONS

In Greek subjects with OSAS, there was no difference in BMI, and female patients were significantly older than male patients. OSAS was diagnosed in men five times more often than in women. AHI was greater in men than in women, but women are more likely than men to have a higher AHI in REM than NREM. Sleep quality is worse in female than in male patients.

Gender difference in sleep profile of severely obese patients with obstructive sleep apnea (OSA)

OBJECTIVES

Few papers addressed the gender difference in the polisomnographic features of obstructive sleep apnea (OSA). In this paper we investigated the sleep architecture and the nocturnal respiratory pattern in a group of severely obese women with OSA compared with a group of men with OSA matched by age and weight.

DESIGN

A cross-sectional study.

SETTING

Primary-care setting.

SUBJECTS, MAIN OUTCOME MEASURES

Anthropometric parameters, respiratory function data and a full night polisomnography were evaluated in a group of 45 obese subjects, 20 females and 25 males, with a previous diagnosis of OSA.

RESULTS

The group of the severely obese women with OSA presented greater disturbances of the sleep architecture than the group of the men does (wake time after sleep onset 92.6+/-52.4 vs 58.2+/-45.2 min, P<0.05; total wake time 104.8+/-51.4 vs 67.8+/-47.4, P<0.05; number of awakenings 15.5+/-3.6 vs 10.2+/-6.215, P<0.001; OSA that occurred almost exclusively during REM sleep (REM OSA) 35% vs 4%, P<0.05) and a reduced sleep efficiency (69.6+/-15.9 vs 80.3+/-14.0%, P<0.05).

CONCLUSIONS

Severely obese women with OSA, even with milder OSA, present greater disturbances of the sleep architecture with a more severe sleep disruption and more frequently REM OSA in comparison with men matched by age and weight.

Sleep in peri-menopausal and post-menopausal women

Despite the fact that a large number of women report sleep disturbances associated with peri-menopausal and post-menopausal periods, there is a surprising lack of literature related to this issue. In fact, there has not been enough work in this area to even definitively establish whether there is a sleep disorder that is specifically related to these life-stage changes. Herein we review the available literature which suggests that insomnia may be directly linked to the changes that occur during the peri/post-menopausal periods. This insomnia appears to be due to night sweats caused by the hormonal changes which occur and which lead to an increase in arousals. Persistence of insomnia symptoms after adequate hormone replacement therapy may indicate that behavioral conditioning of the insomnia initially triggered by the night sweats may have occurred. Alternatively, such an insomnia in a peri/post-menopausal woman could be due to unresolved grief related to going through menopause or could reflect an independent sleep disorder, such as periodic movements of sleep, sleep apnea, depression, anxiety, etc. Whereas menopausal changes do not directly lead to an increase in sleep apnea they seemingly contribute to an increased risk for this disorder. In view of these considerations, we provide guidelines for the proper diagnosis and treatment of peri/post-menopausal women with sleep complaints.

Selected contribution: chronic intermittent hypoxia enhances respiratory long-term facilitation in geriatric female rats

Age and the estrus cycle affect time-dependent respiratory responses to episodic hypoxia in female rats. Respiratory long-term facilitation (LTF) is enhanced in middle-aged vs. young female rats (72). We tested the hypothesis that phrenic and hypoglossal (XII) LTF are diminished in acyclic geriatric rats when fluctuating sex hormone levels no longer establish conditions that enhance LTF. Chronic intermittent hypoxia (CIH) enhances LTF (41); thus we further predicted that CIH would restore LTF in geriatric female rats. LTF was measured in young (3-4 mo) and geriatric (20-22 mo) female Sasco Sprague-Dawley rats and in a group of geriatric rats exposed to 1 wk of nocturnal CIH (11 vs. 21% O2 at 5-min intervals, 12 h/night). In anesthetized, paralyzed, vagotomized, and ventilated rats, time-dependent hypoxic phrenic and XII responses were assessed. The short-term hypoxic response was measured during the first of three 5-min episodes of isocapnic hypoxia (arterial Po2 35-45 Torr). LTF was assessed 15, 30, and 60 min postepisodic hypoxia. Phrenic and XII short-term hypoxic response was not different among groups, regardless of CIH treatment (P > 0.05). LTF in geriatric female rats was smaller than previously reported for middle-aged rats but comparable to that in young female rats. CIH augmented phrenic and XII LTF to levels similar to those of middle-aged female rats without CIH (P < 0.05). The magnitude of phrenic and XII LTF in all groups was inversely related to the ratio of progesterone to estradiol serum levels (P < 0.05). Thus CIH and sex hormones influence the magnitude of LTF in geriatric female rats.

Gender differences in sleep apnea: epidemiology, clinical presentation and pathogenic mechanisms

Sleep apnea syndromes are a common cause of sleepiness and neurocognitive impairment and have been implicated as an independent risk factor for cardiovascular disease. While both epidemiological and sleep clinic-based studies indicate that sleep apnea syndromes are more common in men than in women, the gender difference in prevalence is more marked within the sleep clinic. Reasons for the relative failure of women to attend sleep clinics and the pathophysiologic differences that give rise to the male predominance of sleep apnea syndromes are unknown. The purpose of this review was to examine the literature with regard to these aspects, to provide clinical guidance to improve the reduced attendance of women to sleep laboratories and to stimulate research interest into the causes of these differences.

Surgery for sleep-disordered breathing in female patients

This article focuses on the female patient with sleep-disordered breathing. Sleep-disordered breathing has historically been considered a disease seen primarily in men, but it has become increasingly recognized in women. Recent studies of the general population suggest that almost one third of all obstructive sleep apnea syndrome cases exist in women. A review of current information focusing on the epidemiology, diagnosis, and treatment of the female patient is presented.

Hormone replacement therapy and sleep-disordered breathing

Disordered breathing during sleep is more common among postmenopausal women than among their premenopausal counterparts, possibly because of declining levels of estrogen and progesterone. We examined the relationship between the use of replacement hormones and sleep-disordered breathing in a sample of 2,852 noninstitutionalized women, 50 years of age or older, who participated in the Sleep Heart Health Study. The frequency of apneas and hypopneas per hour of sleep (apnea-hypopnea index) was determined by unattended, single-night polysomnography at the participant's home. The prevalence of sleep-disordered breathing (apnea-hypopnea index of 15 or more) among hormone users (61 of 907) was approximately half the prevalence among nonusers (286 of 1,945). Multivariable adjustment for known determinants of the disorder, including age, body mass index, and neck circumference, has attenuated the association, but only moderately (adjusted odds ratio, 0.55; 95% confidence interval, 0.41 to 0.75). The inverse association between hormone use and sleep-disordered breathing was evident in various subgroups and was particularly strong among women 50 to 59 years old (adjusted odds ratio, 0.36; 95% confidence interval, 0.21 to 0.60). If the observed associations are causal, hormone replacement therapy could have a role in preventing or alleviating sleep-disordered breathing.

Gender differences in sleep apnea: the role of neck circumference

STUDY OBJECTIVES

To determine whether differences in sleep apnea severity between men and women referred to a sleep clinic are related to the differences in neck circumference (NC).

STUDY DESIGN

Case series.

SETTING

University hospital sleep disorders clinic.

PARTICIPANTS

A total of 3,942 patients (2,753 men and 1,189 women) referred to the sleep clinic.

MEASUREMENTS AND RESULTS

All patients underwent nocturnal polysomnography. NC was used as a surrogate measure of upper airway obesity. We found that sleep apnea, defined an the apnea/hypopnea index (AHI) > 10/h, was significantly more frequent (60% vs 32%, chi(2) < 0.0001) and severe (mean +/- SE, 25 +/- 26/h vs 12 +/- 19/h, p < 0.0001) in men than in women. Men had significantly larger NC than women, but the difference became much less pronounced when we normalized NC to body height (0.24 +/- 0.02 vs 0.23 +/- 0.03, p < 0.0001). Men had significantly higher AHI than women even after controlling for age, body mass index (BMI), and neck/height ratio (NHR); analysis of covariance showed that mean AHI was 24.4 +/- 0.4 in men vs 14.8 +/- 0.7 in women (p < 0.0001). This difference persisted even when we matched men and women for NHR and BMI. Finally, multiple regression analysis revealed the following: (1) NHR was the most significant predictor of AHI, accounting for 19% of the variability; and (2) the slope of AHI vs NHR was significantly higher in men than in women.

CONCLUSIONS

We conclude the following: (1) the frequency and severity of sleep apnea in the sleep clinic population is greater in men than women, and (2) factors other than NC, age, and BMI must contribute to these gender differences.

Hormones and breathing

A number of hormones, including hypothalamic neuropeptides acting as neurotransmitters and neuromodulators in the CNS, are involved in the physiologic regulation of breathing and participate in adjustment of breathing in disease. In addition to central effects, some hormones also control breathing at peripheral chemoreceptors or have local effects on the lungs and airways. Estrogen and progesterone seem to protect from sleep-disordered breathing, whereas testosterone may predispose to it. Progesterone and thyroxine have long been known to stimulate respiration. More recently, several hormones such as corticotropin-releasing hormone and leptin have been suggested to act as respiratory stimulants. Somatostatin, dopamine, and neuropeptide Y have a depressing effect on breathing. Animal models and experimental human studies suggest that also many other hormones may be involved in respiratory control.

Women and sleep

Naturally fluctuating hormones (menstrual cycle, through pregnancy or menopausal transition) are not related to marked sleep disturbances in women. It is likely, however, that subsets of women will display a central nervous system vulnerability to hormonal fluctuations so that sleep disturbances manifest as a part of a complex of discomforting symptoms. Sleep is impacted directly through the circadian system or brain sleep regulation or through the development of concurrent functional changes and symptoms. Women are susceptible to sleep-related disorders that are also common in men, such as primary insomnia and SBD although the contributing factors and manifestations may not be the same.

Age and gender effects on serotonin-dependent plasticity in respiratory motor control

We review recent evidence indicating that serotonin-dependent plasticity in respiratory control is influenced by age and gender. Specifically, respiratory long-term-facilitation following intermittent hypoxia decreases with age in male rats, but increases in female rats. We speculate about a possible relationship between age and gender effects on serotonin-dependent plasticity in upper airway motoneuron pools and the prevalence of obstructive sleep apnea.

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.

Determinants of chronic hypercapnia in Japanese men with obstructive sleep apnea syndrome

STUDY OBJECTIVE

To identify the determinants of chronic hypercapnia (ie, PaCO(2), > or = 45 mm Hg) in men with obstructive sleep apnea syndrome (OSAS) without airflow obstruction.

DESIGN

An analysis was conducted of 143 male patients with OSAS, which had been diagnosed by polysomnography (PSG), who had been referred to a university hospital. Patients were classified as hypercapnic (ie, PaCO(2), > or = 45 mm Hg) and normocapnic (ie, PaCO(2), < 45 mm Hg), and obese (ie, body mass index [BMI], > or = 30 kg/m(2)) or nonobese (ie, BMI, < 30 kg/m(2)). Patients with airflow obstruction (ie, FEV(1)/FVC ratio, < 70%) were excluded from the study. Baseline clinical characteristics, pulmonary function, PSG data, and blood gas data were compared between hypercapnic and normocapnic patients. Correlations between PaCO(2) and several anthropometric, respiratory, and polysomnographic variables were determined by stepwise multiple regression analysis.

RESULTS

Fifty-five patients (38%) were hypercapnic. Hypercapnic patients were younger and heavier, and had more abnormalities on pulmonary and PSG testing. Stepwise multiple regression analysis revealed that the PaCO(2) level was influenced significantly by the mean level of arterial oxygen saturation (SaO(2)) during sleep and by the percent of vital capacity (%VC) (R(2) = 0.430; p < 0.0001), indicating that 43% of the total variance in the PaCO(2) could be explained by the mean SaO(2) and %VC in hypercapnic patients. In contrast, only 13% of the total variance in the PaCO(2) was accounted for by the mean SaO(2) and BMI in normocapnic patients (R(2) = 0.134; p = 0.0034). The mean SaO(2), %VC, and PaO(2) were selected as independent variables for predicting the PaCO(2) in obese patients. These variables explained 41% of the total variance in the PaCO(2) (R(2) = 0.407; p < 0.0001), whereas the mean SaO(2) only accounted for 13% of the total variance in PaCO(2) levels in nonobese patients (R(2) = 0.134; p = 0.0064).

CONCLUSION

Nocturnal desaturation and restrictive pulmonary impairment play major roles in determining the PaCO(2) in hypercapnic and obese OSAS patients without airflow obstruction.