Somers, Virend K.

Background— There have been significant bidirectional changes in the prevalence of cardiovascular (CV) risk factors over time in the United States, making the net trend in risk for incident CV disease unknown. We assessed these trends by applying the Framingham Heart Study prediction model to national data. Methods and Results— The National Health and Nutrition Examination Survey (NHANES) II (1976–1980), NHANES III (1988–1994), and NHANES 1999–2004 are cross-sectional representative samples of the noninstitutionalized population of the United States. We excluded people with a history of CV disease, pregnant women, participants with missing CV risk factors data, and individuals outside the Framingham age range of 30 to 74 years. The Framingham risk function was used to estimate the 10-year risk for incident symptomatic CV disease. We calculated the slope of change or rate of change per year between NHANES II and III, and between NHANES III and 1999–2004. The difference between slopes was calculated and compared to zero. The average age-adjusted 10-year CV risk between NHANES II and III decreased from 10.0% to 7.9% between NHANES II and III, with a statistically significant slope ( P <0.001). However, the average age-adjusted CV risk decreased at a lesser magnitude between NHANES III and NHANES 1999–2004 from 7.9% to 7.4% ( P <0.001). These slopes were significantly different ( P <0.0001). In women and middle-aged participants, CV risk did not change between NHANES III and NHANES 1999–2004 ( P =0.40). Conclusions— The estimated net risk for CV disease in the US population decreased from 1976–1980 to 1988–1994 but has changed minimally from 1988–1994 to 1999–2004, particularly in women and middle-aged people.

The combination of metabolic syndrome and obstructive sleep apnea (OSA) has been termed “syndrome Z.” The prevalence of both OSA and metabolic syndrome is increasing worldwide, in part linked to the epidemic of obesity. Beyond their epidemiologic relationship, growing evidence suggests that OSA may be causally related to metabolic syndrome. We are only beginning to understand the potential mechanisms underlying the OSA–metabolic syndrome interaction. Although there is no clear consensus, there is growing evidence that alterations in the hypothalamic–pituitary axis, generation of reactive oxygen species (ROS) due to repetitive hypoxia, inflammation, and generation of adipokines may be implicated in the changes associated with both OSA and metabolic syndrome. Whether some or all of these metabolic alterations mechanistically link OSA to metabolic syndrome remains to be proven, but it is an area of intense scientific interest.

Abstract Rationale We previously demonstrated that children with obstructive sleep apnea have increased blood pressure associated with changes in left ventricular mass index. Others have shown in adults that blood pressure variability is an important predictor of changes in left ventricular mass. The baroreflex system buffers blood pressure changes by varying heart rate. We have thus hypothesized that (1) baroreflex system gain is increased during sleep, improving blood pressure buffering; (2) children with obstructive sleep apnea lack this baroreflex gain increase; and (3) reduced blood pressure buffering results in exaggerated blood pressure variability that is associated with end-organ damage. Objectives Compare measures of left ventricular mass index and nighttime baroreflex gain of healthy children to those of children with obstructive sleep apnea. Methods A total of 169 children (50 control subjects, 63 with mild obstructive sleep apnea, and 56 with severe obstructive sleep apnea) with a mean age of 9.9 years (±2.2) underwent echocardiography followed by polysomnography with continuous blood pressure measurement. Baroreflex gain was calculated in time and frequency domains. Measurements and Main Results Healthy children demonstrated a nighttime pattern of increasing baroreflex gain. Children with obstructive sleep apnea had decreased nighttime baroreflex gain compared with control subjects. Nighttime blood pressure and blood pressure variability were significantly correlated with left ventricular mass index. Conclusions Obstructive sleep apnea is associated with a decrease in nighttime baroreflex gain and an increase in blood pressure variability. This increase is correlated with changes in left ventricular mass index.

Abstract Rationale An association between neurocognitive deficits and pediatric sleep-disordered breathing has been suggested; however, weak correlations between disease severity and functional outcomes underscore the lack of knowledge regarding factors modulating cognitive morbidity of sleep-disordered breathing. Objectives To identify the parameters affected by sleep-disordered breathing that modulate cerebral oxygenation, an important determinant of cognition. A further objective was to use these parameters with demographic data to develop a predictive statistical model of pediatric cerebral oxygenation. Methods Ninety-two children (14 control subjects, 32 with primary snoring, and 46 with obstructive sleep apnea) underwent polysomnography with continuous monitoring of cerebral oxygenation and blood pressure. Analysis of covariance was used to relate the blood pressure, sleep diagnostic parameters, and demographic characteristics to regional cerebral oxygenation. Measurements and Main Results To account for anatomic variability, an index of cerebral oxygenation during sleep was derived by referencing the measurement obtained during sleep to that obtained during wakefulness. In a repeated measures model predicting the index of cerebral oxygenation, mean arterial pressure, rapid eye movement (REM) sleep, female sex, age, and oxygen saturation had a positive effect on cerebral oxygenation levels, whereas arousal index and non-REM (NREM) sleep had a negative effect. Conclusions Increasing mean arterial pressure, age, oxygen saturation, and REM sleep augment cerebral oxygenation, while sleep-disordered breathing, male sex, arousal index, and NREM sleep diminish it. The proposed model may explain the sources of variability in cognitive function of children with sleep-disordered breathing.

ABSTRACT Introduction Severe obstructive sleep apnea has been associated with sexual dysfunction; however, it is unclear whether milder forms of sleep disturbances might also be associated with sexual problems. Aim To evaluate the association between snoring and five measures of sexual dysfunction in a population-based sample of men. Methods A stratified random sample of men residing in Olmsted County, Minnesota completed a questionnaire containing questions from the Brief Male Sexual Function Inventory (BMSFI) and a sleep questionnaire. Main Outcome Measures Levels of sexual drive (libido), erectile function, ejaculatory function, sexual problem assessment, and sexual satisfaction as assessed by the BMSFI. Results Of 827 men with a regular sexual partner, subjects were divided into categories of heavy (N=95), moderate (N=573), and none/mild (N=159) snoring. Their median age was 64 years (range 51–90). The sexual satisfaction domain score was significantly lower in the heavy snoring group (P value=0.01). The odds of low sexual satisfaction was 2.3 (95% CI 1.2, 4.1) among the heavy snorers compared with the none/mild snoring group. This association remained statistically significant after adjustment for smoking, medical comorbidities, and mental health status. However, there was no significant difference in ejaculatory function, erectile function, sexual drive, and sexual problem assessment across snoring categories. Conclusions These data provide evidence of an association between snoring severity and reduced sexual satisfaction in a population of elderly community males. Snoring was not associated with biologic measures of sexual dysfunction.

Abstract With the growing epidemic of obesity in an aging population, obstructive sleep apnea (OSA) is increasingly encountered in clinical practice. Given the acute cardiopulmonary stressors consequent to repetitive upper airway collapse, as well as evidence for cardiovascular homeostatic dysregulation in subjects with sleep apnea, there is ample biologic plausibility that OSA imparts increased cardiovascular risk, independent of comorbid disease. Indeed, observational studies have suggested strong associations with multiple disorders, such as systemic hypertension, heart failure, cardiac arrhythmias, and pulmonary hypertension. Further data in the form of longitudinal cohort studies and randomized controlled trials are accruing to add to the body of evidence. This review examines pathophysiologic mechanisms and explores current concepts regarding the impact of OSA and its treatment on selected clinical disease states.