Longitudinal study of moderate weight change and sleep-disordered breathing

Obstructive sleep apnoea syndrome: underestimated and undertreated

The obstructive sleep apnoea syndrome (OSAS) was first identified only 40 years ago and its clinical importance is increasingly recognized. Although now acknowledged as a worldwide problem, which in Western countries affects 2-4% of middle-aged men and 1-2% of middle-aged women, the majority of affected individuals remain undiagnosed. OSAS is strongly associated with obesity but is also increasingly identified in the less obese, in whom a particular craniofacial structure is an important contributory factor. The prevalence of OSAS is likely to be increasing in parallel with the epidemic of obesity currently occurring in many countries. The common presenting complaints are excessive daytime sleepiness and loud snoring. The sleepiness impairs social functioning, work performance and driving ability, and accounts for a large socio-economic burden on the community. Hypertension is an important independent association. The treatment of choice is nocturnal continuous positive airway pressure which is highly effective and is also cost effective.

Seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure

The National High Blood Pressure Education Program presents the complete Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Like its predecessors, the purpose is to provide an evidence-based approach to the prevention and management of hypertension. The key messages of this report are these: in those older than age 50, systolic blood pressure (BP) of greater than 140 mm Hg is a more important cardiovascular disease (CVD) risk factor than diastolic BP; beginning at 115/75 mm Hg, CVD risk doubles for each increment of 20/10 mm Hg; those who are normotensive at 55 years of age will have a 90% lifetime risk of developing hypertension; prehypertensive individuals (systolic BP 120-139 mm Hg or diastolic BP 80-89 mm Hg) require health-promoting lifestyle modifications to prevent the progressive rise in blood pressure and CVD; for uncomplicated hypertension, thiazide diuretic should be used in drug treatment for most, either alone or combined with drugs from other classes; this report delineates specific high-risk conditions that are compelling indications for the use of other antihypertensive drug classes (angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, beta-blockers, calcium channel blockers); two or more antihypertensive medications will be required to achieve goal BP (<140/90 mm Hg, or <130/80 mm Hg) for patients with diabetes and chronic kidney disease; for patients whose BP is more than 20 mm Hg above the systolic BP goal or more than 10 mm Hg above the diastolic BP goal, initiation of therapy using two agents, one of which usually will be a thiazide diuretic, should be considered; regardless of therapy or care, hypertension will be controlled only if patients are motivated to stay on their treatment plan. Positive experiences, trust in the clinician, and empathy improve patient motivation and satisfaction. This report serves as a guide, and the committee continues to recognize that the responsible physician's judgment remains paramount.

Assessment of the obese patient

Obesity may be the most significant medical problem that health care providers will face over the coming decades. Physicians must aggressively address this chronic disease, providing both preventive and therapeutic care. Because this topic traditionally has not been taught in medical schools, physicians need to acquire the knowledge, skills, and attitudes necessary to be effective obesity care providers. Performing a detailed initial assessment, including an obesity-focused history, physical examination, and selected laboratory and diagnostic tests, is fundamental to the process of care.

Obstructive sleep apnea-hypopnea syndrome

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is characterized by repetitive episodes of airflow reduction (hypopnea) or cessation (apnea) due to upper airway collapse during sleep. Increasing recognition and a greater understanding of the scope of this condition have substantially affected the practices of many clinicians. This review provides practical information for physicians assessing patients with OSAHS. It discusses complications, clinical recognition, the polysomnographic report, and treatment of OSAHS, including strategies for troubleshooting problems associated with continuous positive airway pressure therapy.

Obesity, sleep apnea, and hypertension

Obesity has a high and rising prevalence and represents a major public health problem. Obstructive sleep apnea (OSA) is also common, affecting an estimated 15 million Americans, with a prevalence that is probably also rising as a consequence of increasing obesity. Epidemiologic data support a link between obesity and hypertension as well as between OSA and hypertension. For example, untreated OSA predisposes to an increased risk of new hypertension, and treatment of OSA lowers blood pressure, even during the daytime. Possible mechanisms whereby OSA may contribute to hypertension in obese individuals include sympathetic activation, hyperleptinemia, insulin resistance, elevated angiotensin II and aldosterone levels, oxidative and inflammatory stress, endothelial dysfunction, impaired baroreflex function, and perhaps by effects on renal function. The coexistence of OSA and obesity may have more widespread implications for cardiovascular control and dysfunction in obese individuals and may contribute to some of the clustering of abnormalities broadly defined as the metabolic syndrome. From the clinical and therapeutic perspectives, the presence of resistant hypertension and the absence of a nocturnal decrease in blood pressure in obese individuals should prompt the clinician to consider the diagnosis of OSA, especially if clinical symptoms suggestive of OSA (such as poor sleep quality, witnessed apnea, excessive daytime somnolence, and so forth) are also present.

Weight gain after lung transplantation

BACKGROUND

Weight gain is frequently observed after lung transplantation, but the magnitude, predictors and implications of weight gain after lung transplant are unknown.

METHODS

This retrospective cohort study included 826 lung transplant recipients randomly selected from 12 international transplant centers. We included adult patients with available weight data at baseline and 1 year post-transplant. We examined demographic and clinical predictors of first year weight gain using a multiple linear regression model (n = 579) with percent weight change as the dependent variable. To study the association between first year weight gain and subsequent survival, we performed a Cox proportional hazards analysis. p < 0.05 was considered statistically significant.

RESULTS

The median weight change was 10% (range -32% to 84%). On multi-variate analysis, increasing age and prolonged mechanical ventilation were inversely associated with weight gain; obstructive disease, interstitial disease and increasing ischemic time were positively associated with weight gain. Increasing baseline weight was negatively associated with weight gain in patients with obstructive and interstitial disease. The model accounted for 14% of the variance in weight gain. Patients with weight gain above the median had better subsequent survival (adjusted hazard ratio 0.61, 95% confidence interval 0.41 to 0.90). Infection was a more common cause of death in these patients, whereas malignant deaths were more frequent in patients with below-median weight gain.

CONCLUSIONS

Substantial weight gain occurs in the first year after lung transplantation. The predictors of weight gain may be used to target high-risk patients for early intervention. Higher weight gain is associated with better subsequent survival.

Metabolic disturbances in obesity versus sleep apnoea: the importance of visceral obesity and insulin resistance

Obstructive sleep apnoea (OSA) is a very prevalent disorder particularly amongst middle-aged, obese men, although its existence in women as well as in lean individuals is increasingly recognized. Despite the early recognition of the strong association between OSA and obesity, and OSA and cardiovascular problems, sleep apnoea has been treated as a 'local abnormality' of the respiratory track rather than as a 'systemic illness'. In 1997, we first reported that the pro-inflammatory cytokines interleukin (IL)-6 and tumour necrosis factor-alpha (TNF alpha) were elevated in patients with disorders of excessive daytime sleepiness (EDS) and proposed that these cytokines were mediators of daytime sleepiness. Also, we reported a positive correlation between IL-6 or TNF alpha plasma levels and the body mass index (BMI). In subsequent studies, we showed that IL-6, TNF alpha, leptin and insulin levels were elevated in sleep apnoea independently of obesity and that visceral fat, was the primary parameter linked with sleep apnoea. The association of OSA with insulin resistance and diabetes type 2 has been confirmed since then in several epidemiological and clinical studies. Furthermore, our findings that women with polycystic ovary syndrome (PCOS, a condition associated with hyperandrogenism and insulin resistance) were much more likely than controls to have sleep disordered breathing (SDB) and daytime sleepiness support the pathogenetic role of insulin resistance in OSA. Other findings that support the view that sleep apnoea and sleepiness may be manifestations of a serious metabolic disorder, namely the Metabolic or Visceral Obesity Syndrome, include: obesity without sleep apnoea is associated with daytime sleepiness; PCOS and diabetes type 2 are independently associated with EDS after controlling for SDB, obesity and age; and increased prevalence of sleep apnoea in postmenopausal women, with hormonal replacement therapy associated with a significantly reduced risk for OSA. In conclusion, accumulating evidence provides support to our model of the bi-directional, feedforward, pernicious association between sleep apnoea, sleepiness, inflammation and insulin resistance, all promoting atherosclerosis and cardiovascular disease.

Risks of obesity

Obesity is a chronic disease in the same sense as hypertension and atherosclerosis. The cause of obesity is an imbalance between the energy ingested in food and the energy expended. The excess energy is stored in fat cells that enlarge or increase in number. This hyperplasia and hypertrophy of fat cells is the pathologic lesion of obesity. Enlarged fat cells produce the clinical problems that are associated with obesity, either because of the weight or mass of the extra fat or because of the increased secretion of free fatty acids and numerous peptides from enlarged fat cells. The consequence of these two mechanisms is other diseases, such as diabetes mellitus, gallbladder disease, osteoarthritis, heart disease, and some forms of cancer.

Behavioral and pharmacologic therapy of obstructive sleep apnea

Previous attempts at using pharmacologic agents in the treatment of OSA have been disappointing. Medroxyprogesterone has not been found to be useful in the treatment of OSA. Use of protriptyline is limited by frequent side effects, but its role in mild and REM-related OSA must be clarified. SSRIs seem to be ineffective in treatment of severe OSA. Further studies are needed to determine their effect in persons with mild disease. This is important because patients with mild OSA (AHI < 15 hours) are most likely to be noncompliant with CPAP therapy [91]. A recent systematic review of drug treatments for OSA concluded that the current data do not support the use of any drug as an alternative to CPAP [92]. Of 56 studies identified, only 9 studies met methodologic criteria. Clearly, basic research and adequately powered clinical trials are needed to identify an effective medication for OSA.

Menopausal status and sleep-disordered breathing in the Wisconsin Sleep Cohort Study

Menopause is considered to be a risk factor for sleep-disordered breathing, but this hypothesis has not been adequately tested. The association of premenopause, perimenopause, and postmenopause with sleep-disordered breathing was investigated with a population-based sample of 589 women enrolled in the Wisconsin Sleep Cohort Study. Menopausal status was determined from menstrual history, gynecologic surgery, hormone replacement therapy, follicle-stimulating hormone, and vasomotor symptoms. Sleep-disordered breathing was indicated by the frequency of apnea and hypopnea events per hour of sleep, measured by in-laboratory polysomnography. Multivariable logistic regression was used to estimate odds ratios for having 5 or more and 15 or more apnea and hypopnea events per hour. Odds ratios (95% confidence interval), adjusted for age, body habitus, smoking, and other potential confounding factors, for 5 or more apnea and hypopnea events per hour were 1.2 (0.7, 2.2) with perimenopause and 2.6 (1.4, 4.8) with postmenopause; odds ratios for 15 or more apnea and hypopnea events per hour were 1.1 (0.5, 2.2) with perimenopause and 3.5 (1.4, 8.8) with postmenopause. The menopausal transition is significantly associated with an increased likelihood of having sleep-disordered breathing, independent of known confounding factors. Evaluation for sleep-disordered breathing should be a priority for menopausal women with complaints of snoring, daytime sleepiness, or unsatisfactory sleep.

The role of oral appliances in treating obstructive sleep apnea

BACKGROUND

Sleep-related breathing disorders are common and often are associated with vascular complications such as arterial hypertension, coronary heart disease and stroke. The most widely studied form of these disorders is obstructive sleep apnea. Patients usually are diagnosed with obstructive sleep apnea years after the onset of symptoms, which generally are nonspecific and include excessive daytime sleepiness, chronic fatigue and habitual snoring. The risk factors for sleep apnea are obesity, advancing age, male sex and maxillofacial abnormalities. This review focuses on the diagnosis and treatment of obstructive sleep apnea and, specifically, on the utility of oral appliances in the management of this disorder.

METHODS

The review is based on a MEDLINE search for articles in English on this topic. The article discusses results of randomized studies and prospective case series.

CLINICAL IMPLICATIONS

Several treatment options are quite effective. Nasal continuous positive airway pressure, with an overall acceptance rate of 70 percent, is the most widely used treatment modality. Maxillofacial surgery, although effective, is reserved for patients who have not responded to the more conventional therapies. Newer methods include application of oral appliances. Oral appliances have been shown to alleviate the severity of respiratory disturbances during sleep by about 60 percent, with an overall acceptance rate of 75 percent. The long-term complications generally are minor and are related to occlusal changes and temporomandibular joint discomfort.

CONCLUSIONS

With the advent of oral appliances, dentists are increasingly involved in managing the care of patients with sleep-related breathing disorders. Further studies are needed to determine the long-term complications of this type of intervention for the treatment of sleep-related breathing disorders.

Weight control and the management of obesity after menopause: the role of physical activity

BACKGROUND

Postmenopausal women have an increased tendency for gaining weight. The declines of endogenous estrogen, together with physical inactivity, are probably the major causes of this phenomenon. Postmenopausal overweight and obesity leads to increased rates of hypertension, diabetes mellitus, coronary artery disease, and all cause mortality. Additional consequences may include hormone-dependent cancer, gallstones, nephrolithiasis, and osteoarthritis. Weight loss can reverse many of these complications, reduce the number and dosages of medications used, and improve longevity. This difficult task requires lifestyle modification.

OBJECTIVES

To review the current information about the effects of physical activity on postmenopausal weight gain and its consequences and to provide basic strategies to treat obesity during the menopause transition.

METHODS

A Medline search together with a manual search of selected articles.

CONCLUSION

Several options for weight loss are available, yet lifestyle modification is essential in managing postmenopausal obesity and overweight. While this demands dietary and behavioral changes, a major element of this modification is regular physical activity, which reduces obesity-related morbidity and mortality. The amendment to a healthier lifestyle is achievable at the postmenopausal years. All medical personnel should advocate against overweight and obesity and provide tools for their management.

Sleep complaints and epilepsy: the role of seizures, antiepileptic drugs and sleep disorders

Patients with epilepsy commonly complain of daytime sleepiness and poor sleep quality. These problems are frequently attributed to antiepileptic drugs and seizures. Antiepileptic drugs and seizures have effects on sleep architecture often leading to daytime sleepiness. However, sleep symptoms may also be caused by poor sleep hygiene and primary sleep disorders. Primary sleep disorders should be suspected in patients with persistent daytime sleepiness, particularly those on AED monotherapy or with low serum drug concentrations and well-controlled seizures. Treatment of sleep disorders and improved sleep hygiene may improve seizure control and quality of life.

Anatomic determinants of sleep-disordered breathing across the spectrum of clinical and nonclinical male subjects

OBJECTIVES

We wished to determine the independent contribution of craniofacial dimensions of the upper airway to sleep-disordered breathing (SDB) in subjects who spanned the entire continuum of SDB. We also determined the interactive effects of body mass index (BMI) and age on the relationship between airway dimensions and SDB.

DESIGN AND SUBJECTS

We studied 142 nonclinical male subjects in a working community population (average age, 47 years; average BMI, 29; average +/- SD apnea/hypopnea index [AHI], 20 +/- 20/h), and 62 patients with obstructive sleep apnea (average age, 47 years; average BMI, 32; average +/- SD AHI, 48 +/- 35/h. We determined the AHI from overnight polysomnography and the number of oxygen desaturations (> or = 2%) per hour of sleep. We used lateral facial cephalometric radiographs to measure 41 anatomic landmarks and 55 dimensions in the upper airway.

SETTING

A university hospital and a sleep-disorders clinic.

DATA ANALYSIS

We used stepwise regression analysis to determine the independent contributions of measured variables to SDB.

MEASUREMENTS AND RESULTS

In the entire study population (n = 204), variations in BMI and six measures of craniofacial morphology accounted equally for one half of the total variance in AHI, and their interactive effects accounted for an additional 15%. Membership in the clinical or nonclinical group per se had no significant influence on these relationships. The single most important cephalometric variable in predicting AHI severity was the horizontal dimension of the maxilla (ie, porion vertical to supradentale [PV-A] distance). When the PV-A distance was relatively narrow (< 97 mm) the probability of having mild (AHI, 15 to 30/h) to severe (AHI > 30/h) SDB increased fivefold to sevenfold in nonobese subjects and threefold in obese subjects. Thus, in nonobese subjects (average BMI, 25 +/- 2) and in subjects with narrow upper airway dimensions, four cephalometric dimensions were the dominant predictors of AHI, accounting for 50% of the variance. However, in subjects with a large anteroposterior facial dimension, BMI was the major predictor of AHI and a BMI > 28 increased the probability of moderate-to-severe sleep apnea by approximately fivefold. Finally, the combination of cephalometric dimensions and BMI accounted for an increasing amount of the variance in AHI as the severity of AHI increased.

CONCLUSIONS

Across the population spectrum of SDB, four cephalometric dimensions of the upper airway in combination with BMI accounted independently for up to two thirds of the variation in AHI; and the relative contribution of these two sets of determinants of AHI varied depending on airway size, obesity, and the amount of SDB.

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.