Abnormalities in autonomic function in obese boys at-risk for insulin resistance and obstructive sleep apnea.

Study objectivesCurrent evidence in adults suggests that, independent of obesity, obstructive sleep apnea (OSA) can lead to autonomic dysfunction and impaired glucose metabolism, but these relationships are less clear in children. The purpose of this study was to investigate the associations among OSA, glucose metabolism, and daytime autonomic function in obese pediatric subjects.MethodsTwenty-three obese boys participated in: overnight polysomnography; a frequently sampled intravenous glucose tolerance test; and recordings of spontaneous cardiorespiratory data in both the supine (baseline) and standing (sympathetic stimulus) postures.ResultsBaseline systolic blood pressure and reactivity of low-frequency heart rate variability to postural stress correlated with insulin resistance, increased fasting glucose, and reduced beta-cell function, but not OSA severity. Baroreflex sensitivity reactivity was reduced with sleep fragmentation, but only for subjects with low insulin sensitivity and/or low first-phase insulin response to glucose.ConclusionsThese findings suggest that vascular sympathetic activity impairment is more strongly affected by metabolic dysfunction than by OSA severity, while blunted vagal autonomic function associated with sleep fragmentation in OSA is enhanced when metabolic dysfunction is also present

Nocturia, Sleep-Disordered Breathing, and Cardiovascular Morbidity in a Community-Based Cohort

Background: Nocturia has been independently associated with cardiovascular morbidity and all-cause mortality, but such studies did not adjust for sleep-disordered breathing (SDB), which may have mediated such a relationship. Our aims were to determine whether an association between nocturia and cardiovascular morbidity exists that is independent of SDB. We also determined whether nocturia is independently associated with SDB. Methodology/Principal Findings: In order to accomplish these aims we performed a cross-sectional analysis of the Sleep Heart Health Study that contained information regarding SDB, nocturia, and cardiovascular morbidity in a middle-age to elderly community-based population. In 6342 participants (age 63±11 [SD] years, 53% women), after adjusting for known confounders such as age, body mass index, diuretic use, diabetes mellitus, alpha-blocker use, nocturia was independently associated with SDB (measured as Apnea Hypopnea index >15 per hour; OR 1.3; 95%CI, 1.2-1.5). After adjusting for SDB and other known confounders, nocturia was independently associated with prevalent hypertension (OR 1.23; 95%CI 1.08-1.40; P = 0.002), cardiovascular disease (OR 1.26; 95%CI 1.05-1.52; P = 0.02) and stroke (OR 1.62; 95%CI 1.14-2.30; P = 0.007). Moreover, nocturia was also associated with adverse objective alterations of sleep as measured by polysomnography and self-reported excessive daytime sleepiness (P<0.05). Conclusions/Significance: Nocturia is independently associated with sleep-disordered breathing. After adjusting for SDB, there remained an association between nocturia and cardiovascular morbidity. Such results support screening for SDB in patients with nocturia, but the mechanisms underlying the relationship between nocturia and cardiovascular morbidity requires further study. MeSH terms: Nocturia, sleep-disordered breathing, obstructive sleep apnea, sleep apnea, polysomnography, hypertension

Daytime sleepiness and functional outcomes in older adults with diabetes

Purpose This secondary analysis examined the effect of excessive sleepiness on daytime function in older adults with diabetes from the National Sleep Foundation's Sleep and Aging poll. Methods Respondents were older adults (N = 1506; age range, 55-84 years) evaluated by telephone survey on their sleep duration, sleep disturbances, daytime functional outcomes, and self-reported height, weight, and comorbidities. Results Approximately 16% (n = 244) of the sample acknowledged a diagnosis of diabetes; they were older, had more comorbidities, had a higher body mass index (BMI), and were more likely to be sleepy during the daytime than nondiabetic respondents (all P <.05). Respondents with diabetes who reported frequent daytime sleepiness (n = 50; 20%) had significantly (P <.05) higher BMI, lower self-rated health, and more sleep disturbances than those who were not sleepy (n = 194). Sleepy respondents with diabetes also reported more frequent feelings of depression, decreased pleasure in life, naps, feeling drowsy, or dozing off while driving (all P <.05). Excessive sleepiness was significantly associated (P <.001) with an increased risk for depressive symptoms while controlling for BMI, age, and number of comorbidities. Conclusions These results indicate that sleep disturbances affect not only sleep quality but also daytime function in older adults with diabetes

Revisiting the association between cardiovascular risk factors and diabetes: Data from a large population-based study

Purpose: The purpose of this study was to examine the association between cardiovascular risk factors and the presence of diabetes in a large population-level dataset. Methods: A secondary analysis was conducted using data from the 2007 Behavioral Risk Factor Surveillance System, a population-based survey (n = 403,137) conducted in the United States. Results: The majority of the respondents were middle-aged and overweight. Approximately half of the sample reported little or no physical activity. Estimates from a logistic regression model for a weighted sample of white, black, and Hispanic adults revealed that having hypertension or elevated cholesterol was a strong predictor of diabetes even when controlling for age, gender, race, education, income, body mass index, smoking status, and physical activity. Conclusions: The results confirmed the importance of diabetes educators counseling patients with hypertension or hypercholesterolemia about their increased risk for developing diabetes. © 2009 The Author(s)