Increasing systemic chronic inflammation mediated the association between poor sleep during pregnancy and gestational cardiovascular health.

OBJECTIVES: This study aimed to examine the association between sleep behaviors and cardiovascular health (CVH) during pregnancy and test whether high-sensitivity C-reactive protein (hs-CRP) mediates this association. METHODS: The study included 4204 pregnant women from the Maternal and Infant Health cohort study in Hefei (MIH-Hefei). Information on sleep (chronotype, sleep duration, snoring, daytime sleepiness, and insomnia) was collected through a touch-screen structured questionnaire at 16-23 weeks' gestation. CVH (body mass index, blood pressure, total cholesterol, glucose, and smoking) and hs-CRP were measured at 24-28 weeks' gestation. The role of hs-CRP in the association between sleep and CVH was explored in a mediation analysis, while adjusting for multiple confounding factors. RESULTS: Poor sleep score was significantly associated with poor gestational CVH metrics, including an RR of 0.872 (95% CI, 0.810, 0.938) for having all ideal (vs. any nonideal) CVH metrics; hs-CRP level was significantly associated with poor gestational CVH metrics, including an RR of 0.531 (95% CI, 0.432, 0.609) for having all ideal (vs. any nonideal) CVH metrics. Sleep scores were positively correlated with hs-CRP level (ß, 0.020, 95% CI, 0.006, 0.034). Mediation analysis revealed that the association between sleep and CVH mediated by hs-CRP was 12.31% (indirect effect, -0.0095, 95% CI, -0.0167, -0.0042). CONCLUSIONS: Poor sleep during pregnancy, particularly late chronotype and snoring, may worsen CVH by increasing systemic chronic inflammation.

Effects of continuous positive airway pressure on resolvin and matrix metalloproteinase-9 in patients with obstructive sleep apnea.

PURPOSE: Resolvin is a checkpoint controller in inflammation. Matrix metalloproteinase-9 (MMP-9) is an airway remodeling regulator. We evaluated the levels of resolvin and MMP-9 protein in the serum and exhaled breath condensate (EBC) before and after continuous positive airway pressure (CPAP) treatment. METHOD: We enrolled 20 non-OSA snorers and 40 patients with moderate to severe OSA scheduled for CPAP treatment. ELISA was used to assess resolvin and MMP-9 levels in the serum and EBC. All patients underwent sleep assessment at baseline and 3 months after CPAP. RESULTS: There was no between-group difference; moreover, there were no differences in the pre- and post-treatment serum levels of resolvin and MMP-9 in patients with OSA. Compared with non-OSA snorers, patients with OSA had lower resolvin and higher MMP-9 levels in the EBC. After CPAP treatment, the EBC levels of resolvin and MMP-9 in patients with OSA returned to normal. CONCLUSIONS: Successful OSA treatment by CPAP can normalize EBC levels of resolvin and MMP-9.

The association between plasma metabolites and sleep quality in the Southall and Brent Revisited (SABRE) Study: A cross-sectional analysis.

We examined the association between plasma metabolites and abnormal sleep patterns using data from the Southall and Brent REvisited (SABRE) cohort. Nuclear magnetic resonance spectroscopy provided 146 circulating plasma metabolites. Sleep questionnaires identified the presence or absence of: difficulty falling asleep, early morning waking, waking up tired, and snoring. Metabolites were compared between the sleep quality categories using the t test, and then filtered using a false discovery rate of 0.05. Generalised linear models with logit-link assessed the associations between filtered metabolites and sleep phenotypes. Adjustment was made for important demographic and health-related covariates. In all, 2,718 participants were included in the analysis. After correcting for multiple testing, three metabolites remained for difficulty falling asleep, 59 for snoring, and none for early morning waking and waking up tired. After adjusting for sex, age, ethnicity and years of education, 1 standard deviation increase in serum histidine and valine associated with lower odds of difficulty falling asleep by 0.89-0.90 (95% confidence intervals [CIs] 0.80-0.99). Branched-chain and aromatic amino acids (odds ratios [ORs] 1.19-1.25, 95% CIs 1.09-1.36) were positively associated with snoring. Total cholesterol in low-density lipoprotein (OR 0.90, 95% CI 0.83-0.97) and high-density lipoprotein (OR 0.88, 95% CI 0.81-0.95) associated with lower odds of snoring. In the fully adjusted model, most associations persisted. To conclude, histidine and valine associated with lower odds of difficulty falling asleep, while docosahexaenoic acid and cholesterol in low-density lipoprotein and high-density lipoprotein subfractions associated with lower odds of snoring. Identified metabolites could provide guidance on the metabolic pathways associated with adverse sleep quality.

The Effects of Obstructive Sleep Apnea on Risk factors for Cardiovascular diseases.

INTRODUCTION: Obstructive sleep apnea (OSA) is known to cause variety of cardiovascular diseases. OBJECTIVE: The aim of this study was to examine the correlation between polysomnography (PSG) and risks factor for coronary heart disease in patients suspected to have OSA. METHODS: A total of 108 consecutive adult habitual snorers underwent PSG. We assessed patients using the respiratory disturbance index (RDI), the Epworth sleepiness scale (ESS), body mass index (BMI), fasting serum total cholesterol, triglycerides (TGs), and C-reactive protein (CRP). RESULTS: Mean RDI scores were 0.53, 10.6, 27.3, and 45.1 in the control group (n = 21), mild (n = 29), moderate (n = 31), and severe (n = 27), respectively. Partial correlation analysis showed that patients' RDI score was significantly correlated with CRP after adjustment for BMI. Partial correlation analysis showed that the mean ESS score correlated significantly with the CRP level after adjustment for BMI. Partial correlation analysis showed that the mean least oxygen saturation was significantly correlated with CRP after adjustment for BMI Pearson's correlation coefficients examining the relationship between BMI and total cholesterol; TG and CRP were found to be 0.531, 0.401, and 0.321. The correlation of CRP levels with disease severity as assessed by RDI, ESS, and least oxygen saturation was significant after adjustment for BMI. CONCLUSIONS: Patients with OSA have elevated serum levels of high-sensitivity-CRP, a marker for inflammation and an independent risk predictor for cardiovascular morbidity.

Measures of nocturnal oxyhemoglobin desaturation in children with neuromuscular disease or Prader-Willi syndrome.

OBJECTIVES: Evidence for nocturnal oximetry interpretation in patients with abnormal neuromuscular function is limited. We aimed to compare children with neuromuscular disease (NMD) or Prader-Willi syndrome (PWS) to otherwise healthy subjects with obstructive sleep-disordered breathing (SDB) or without respiratory disorder (controls) regarding nocturnal oximetry parameters. METHODS: We analyzed recordings from children with: (a) NMD; (b) PWS; (c) snoring and adenotonsillar hypertrophy and/or obesity (SDB); and (d) controls. Outcomes included: (a) basal SpO2 ; (b) proportions of subjects with McGill oximetry score (MOS) >1 (clusters of desaturations); and (c) desaturation index (SpO2 drops ≥3%/h-ODI3). RESULTS: Data of 12 subjects with NMD (median age, 5.2 years; IQR, 2.7, 8.2), 14 children with PWS (5 years; 2.3, 6.9), 21 children with SDB (5.8 years; 4.6, 9.6), and 20 controls (6.2 years; 5.4, 11.2) were analyzed. Children with NMD, PWS, and SDB had lower basal SpO2 than controls (95.6% [94.5%, 96.9%], 96.2% [95.1%, 97.4%], 96.1% [95.8%, 97.5%] vs 97.8% [97.2%, 97.9%], respectively; (P < .01). NMD and PWS showed the greatest negative effect on basal SpO2 (P < .05). Children with SDB or PWS had a higher risk of MOS >1 than patients with NMD (OR, 25.9 [95% CI, 3.4-200.4] and 9.5 [1.5-62.6]). NMD, PWS, and SDB were similar regarding ODI3, which was elevated compared to ODI3 in controls (P < .05). Frequent desaturations predominated in NMD, while periods of sustained desaturation were noted in NMD and PWS. CONCLUSION: PWS and NMD have a negative effect on basal SpO2 , while clusters of desaturations are prevalent in patients with PWS or obstructive SDB.

The cardiovascular risk in paediatrics: the paradigm of the obstructive sleep apnoea syndrome.

BACKGROUND: Obstructive sleep apnoea syndrome (OSAS) describes a spectrum of abnormal breathing patterns during sleep characterised by snoring, increased upper airway resistance and pharyngeal collapsibility, with alteration of normal oxygenation and ventilation. Intermittent desaturations during sleep have multi-organ implications. Adults with OSAS have an increased risk of developing a dysfunctional endothelium that is characterised by greater adherence of inflammatory mediators to endothelial cells and hypercoagulability. There is increasing evidence to show that risk factors for comorbid cardiovascular disease (CVD) can develop during childhood and adolescence and are likely to continue over time. Risk factors for CVD include both modifiable factors and factors that cannot be changed. MATERIALS AND METHODS: Using the MEDLINE® electronic database, we reviewed the scientific literature for published studies evaluating the association between sleep-disordered breathing and cardiovascular damage in children. RESULTS: In this review, we show the role of blood markers in demonstrating the inflammation caused by intermitted oxygen desaturations during sleep in both healthy and obese children. Several instrumental techniques, in addition to serum biomarkers, can be used to assess vascular endothelial damage and its deterioration in the form of a pre-atherosclerotic condition. The confirmation of their role as markers of inflammation and vascular damage is supported by normalisation after resolution or improvement of the sleep-disordered breathing with surgery. DISCUSSION: Great attention should be given to this condition in infants and children as it will significantly affect their present and future well-being as they grow into adulthood. Healthcare professionals, especially paediatricians, should be trained to recognise the signs and symptoms of the disease in order to send children forward for specialist care in centres dealing with sleep-disordered breathing.

Effects of somatotropic axis on cognitive dysfunction of obstructive sleep apnea.

PURPOSE: Obstructive sleep apnea (OSA) is associated with a variety of neuroendocrine disorders and may lead to many complications, including cognitive dysfunction. The aim of this study was to assess the change of somatotropic axis and to detect the relation between somatotropic axis hormone and cognitive dysfunction. METHODS: Sixty-six patients with OSA and 16 healthy controls were enrolled in this cross-sectional study. Cognitive function assessment using the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) and polysomnography were performed on all individuals. Blood samples were taken the next morning following the polysomnography and the level of serum growth hormone-releasing hormone (GHRH) and growth hormone (GH) were analyzed by enzyme-linked immunosorbent assay. RESULTS: Compared with the control group, OSA patients showed significantly lower serum GH level (p < 0.05), whereas no statistical significance of GHRH level was found. In addition, lower MMSE and MoCA scores were found only in the severe OSA patients when compared with the controls. Furthermore, in severe OSA patients with cognitive dysfunction (MMSE score < 27 and MoCA score < 26), serum GHRH and GH levels were significantly lower than those without cognitive dysfunction. Logistic analysis revealed that cognitive dysfunction in severe OSA patients was associated with micro-arousal index and the level of serum GHRH and GH. CONCLUSION: Decreased serum GH and GHRH levels were found among severe OSA patients with cognitive dysfunction who were overweight, which might promote the occurrence of cognitive dysfunction.

Clinical characteristics of snoring patients with primary aldosteronism and obstructive sleep apnea-hypopnea syndrome.

The 2016 guideline on the work-up of primary aldosteronism recommended that patients with obstructive sleep apnea-hypopnea syndrome (OSAS) be screened. This study aimed to identify the clinical characteristics of snoring patients with primary aldosteronism (PA) complicated by OSAS. Sixty-eight self-reported or witnessed snoring patients and 609 non-snoring patients diagnosed with PA between 2010 and 2015 were recruited in this retrospective study. Compared to non-snoring patients, snoring patients had significantly (P < 0.05) higher body mass index (BMI), diastolic blood pressure (DBP), and serum and urinary sodium, as well as lower estimated glomerular filtration rate (eGFR). Moreover, snoring patients exhibited significantly (P < 0.01) higher plasma renin activity levels and lower plasma aldosterone levels and aldosterone-to-renin activity ratios (ARRs) than patients with PA alone. When age, sex, duration of hypertension, and BMI were matched between groups, snoring patients still showed significantly (P < 0.05) higher plasma renin activity, serum and urinary sodium, and lower ARR and eGFR than those in the PA-only group. All 68 snoring patients underwent polysomnography, with 7 having mild (apnea-hypopnea index (AHI) ≥ 5 and <15), 21 moderate (AHI ≥ 15 and <30), and 40 severe (AHI ≥ 30) OSAS. The BMI of patients with OSAS was negatively correlated with the lowest SaO2 (r = -0.318, P = 0.018) but not with the AHI. In conclusion, snoring patients with PA tend to have increased BMI and DBP, as well as decreased eGFR and ARR. Snoring patients with PA had higher prevalence of moderate-to-severe OSAS.

Snoring and markers of fetal and placental wellbeing.

INTRODUCTION: Snoring, the symptom of partial airway obstruction during sleep, is a common complaint during pregnancy and is associated with adverse perinatal outcomes. Mechanisms underlying this association have not been studied. We investigated the relationship between snoring in pregnancy and maternal serum markers of feto-placental wellbeing. METHODS: We conducted a secondary analysis of a cross sectional study designed to investigate perinatal outcomes of sleep-disordered breathing. Women admitted for delivery were systematically selected and answered a questionnaire about snoring using the Multivariable Apnea Prediction Index. Participants who had screening markers measured were included and divided into snorers and non -snorers. Markers measured included first and second trimester Down syndrome screening markers, reported as multiples of the median (MoM). An additional analysis was performed with snorers categorized as acute or chronic snorers based on duration of snoring in relation to pregnancy. RESULTS: While significant differences were noted in co-morbid maternal medical conditions between snorers and non-snorers, there were no significant differences in the neonatal outcomes assessed between the two groups. No significant differences were noted in any of the first trimester (PAPP-A) or second trimester (AFP, uE3, hCG, inhibin-A) markers between snorers and non-snorers, p > 0.25. In addition, no significant differences in marker levels were noted between acute and chronic snorers. CONCLUSION: Snoring is not associated with alterations in the markers of fetal or placental wellbeing tested here and suggests that there are alternative mechanisms underlying the association between snoring and adverse perinatal outcomes.

The Apnea-Hypopnea Index Underestimates Systemic Inflammation in Women with Sleep-Disordered Breathing.

BACKGROUND: Evidence suggests that sleep-related respiratory and related metabolic compromise may vary between females and males with sleep-disordered breathing (SDB). Our purpose was to elucidate possible gender differences in sleep-associated respiratory and inflammatory parameters in patients with SDB. MATERIALS AND METHODS: A consecutive number of SDB patients (46 females and 167 males) who underwent polysomnography were retrospectively reviewed. Fibrinogen and C-reactive protein (CRP) concentration, apnea index (ApnI), hypopnea index (HypI), apnea-hypopnea index (AHI), average and minimal SpO2, duration of snoring, age, and body mass index (BMI) were compared between sexes. Spearman's ρ correlation coefficients between parameters were also calculated. RESULTS: ApnI and AHI were significantly higher in males. Correlation analysis revealed striking gender differences: only in females, CRP concentration was highly correlated with snoring duration (r = 0.4393), BMI (r = 0.7147), minimal SpO2 (r = -0.4357), and average SpO2 (r = -0.4547); in females, HypI was more strongly correlated with AHI (r = 0.8778), average SpO2 (r = -0.5765), minimal SpO2 (r = -0.5817), and fibrinogen concentration (r = 0.4614) than in males (r = 0.4373; -0.3295; -0.2969; and 0.0887, respectively); in females, age had a much more pronounced effect on ApnI, HypI, AHI, average oxygen saturation (SaO2), minimal SaO2, snoring duration, and CRP and fibrinogen concentration. CONCLUSIONS: Respiratory compromise in females with SDB is more strongly associated with systemic inflammation than in males with SDB. Although females display a pathological AHI less frequently than males, they reach quite similar pathological SaO2, CRP, and fibrinogen values. Therefore, AHI may underestimate the pathophysiological systemic effects of SDB in females.

The serum leptin level in non-obese patients with obstructive sleep apnea.

OBJECTIVE: This study aimed to determine the association between the severity of obstructive sleep apnea (OSA) and the serum leptin level in non-obese OSA patients. METHODS: This prospective case-control study included non-obese OSA patients that presented with sleep-related disturbances and underwent polysomnography (PSG) between April 2015 and June 2016. The serum leptin level was measured and its relationship to PSG parameters was investigated. RESULTS: The study included 73 OSA patients (20 female and 53 male) with a mean age of 41.1±11.5 years and mean body-mass index (BMI) of 26.4±2.7kgm-2. The serum leptin level in 44 patients with moderate/severe OSA (AHI ≥15) was 3.4±2.6ngmL-1, versus 4.5±3.8ngmL-1 in 29 patients with snoring/mild OSA (AHI <15) (P=0.20). There were not any correlations between any of the PSG parameters and the serum leptin level, but there was a significant correlation between the leptin level and BMI (r=0.345, P<0.01). CONCLUSION: The serum leptin level does not differ significantly between non-obese OSA patients with moderate/severe and snoring/mild OSA. Obesity is the primary factor associated with the serum leptin level.

Glycated hemoglobin and sleep apnea syndrome in children: beyond the apnea-hypopnea index.

PURPOSE: Snoring and obstructive sleep apnea syndrome (OSA) are frequent conditions in pediatrics. Glycated hemoglobin (HbA1C) is a useful homeostatic biomarker of glycemia and may reflect alterations deriving from sleep breathing disorders. The aim of this study was to relate the severity of OSA with blood HbA1C levels in children. METHODS: A descriptive observational study in snoring patients was performed. All patients underwent a sleep study and classified either as simple snorers (apnea-hypopnea index; AHI ≤ 1 episodies/h) or as OSA patients (AHI > 1 episodes/h). In the following morning, a blood glycemic profile (fasting glucose, insulin, HbA1C, and the HOMA index) was performed to every individual. RESULTS: A total of 48 patients were included. HbA1C levels were shown to be increased in the moderate OSA (AHI > 5 episodes/h) group (5.05 ± 0.25 vs. 5.24 ± 0.29%; p = 0.019). Significant correlations were found between HbA1C values and AHI (r = 0.345; p = 0.016) and also with oxygen desaturation index (r = 0.40; p = 0.005). Correlations remained significant after adjusting by age and body mass index. The AHI-associated change in HbA1C was 13.4% (p = 0.011). CONCLUSIONS: In the pediatric population, HbA1C is a biomarker associated with OSA severity, and this relationship is age- and obesity-independent. The fact that this association was observed in snoring patients could help the physician in the distinction between those patients affected with OSA and those with simple snoring. Therefore, HbA1C measurement could play a major role in the diagnosis and the management of the syndrome.

Snoring and components of metabolic syndrome in Southeastern Chinese adults: A community-based study.

INTRODUCTION: Snoring has been associated with a number of abnormal conditions, but little work has been done on its association with components of metabolic syndrome based on the epidemiology in Chinese adults. OBJECTIVE: This study aimed to investigate the association between snoring and components of metabolic syndrome in southeastern Chinese adults. METHODS: A two-stage, cross-sectional community-based study was performed in Fuzhou, Southeast China, from 2005 to 2009. Stage 1: 5500 subjects were administered a questionnaire. Data on self-reported snoring status, daytime somnolence, demographic data, disease histories, and potential confounders were collected and anthropometric measurements were performed. Stage 2: 1000 subjects who were already investigated underwent a blood test and measurement of blood pressure. RESULTS: Data from 4286 subjects were available; 606 subjects were habitual snorers. The prevalence of overweight or obesity, hyperglycemia, hypertension, and dyslipidemia in occasional and habitual snorers was higher than that in the study population (16.66%, 7.89%, 10.52%, and 5.81%, respectively). A significantly increasing trend based on snoring frequency existed in the prevalence of metabolic disorders. The prevalence of components of metabolic syndrome continued to be significantly associated with snoring frequency after controlling confounding factors. Odds ratios of suffering from the aforementioned conditions for occasional and habitual snorers were 1.5-2.5 (P < 0.05) and 2.4-4.8 (P < 0.001) times higher, respectively, compared with nonsnorers. CONCLUSIONS: The prevalence of snoring and components of metabolic syndrome is high in southeastern Chinese adults. Both habitual and occasional snoring are closely associated with metabolic disorders independent of confounding factors.

A Gender-Specific Association between Self-Reported Snoring and Hemoglobin A1c Levels in a General Population without Type 2 Diabetes Mellitus.

PURPOSE: We explored whether a gender difference was evident in terms of the associations of snoring with hemoglobin A1c (HbA1c) and homeostatic model assessment-insulin resistance (HOMA-IR) levels in a healthy population without type 2 diabetes mellitus (DM). MATERIALS AND METHODS: We analyzed 2706 males and 4080 females who participated in the baseline survey of the Namwon Study. In terms of self-reported snoring frequency, participants were classified as non-snorers or occasional (1-3 days/week), frequent (4-6 days/week), or constant (7 days/week) snorers. Participants with DM, defined as a fasting blood glucose level ≥126 mg/dL and/or use of insulin or hypoglycemic medication, were excluded from the analysis. RESULTS: In females, the fully adjusted mean (95% confidence interval) HbA1c levels in non-snorers and in occasional, frequent, and constant snorers were 5.53% (5.47-5.59%), 5.53% (5.47-5.59%), 5.57% (5.49-5.64%), and 5.57% (5.51-5.64%), respectively, reflecting a dose-response relationship (p trend=0.004). Compared with female non-snorers, the risk of an elevated HbA1c level (top quintile, ≥5.9%) in constant snorers remained significant (odds ratio 1.30, 95% confidence interval 1.02-1.66) after full adjustment. In addition, in females, a significant linear trend in HbA1c level odds ratio by increased snoring frequency was apparent (p trend=0.019 in model 3). In contrast, no significant association between snoring frequency and HbA1c level was identified in males. No significant association between snoring frequency and HOMA-IR was detected in either gender. CONCLUSION: We discovered a gender-specific association between snoring and HbA1c level in a healthy, community-dwelling population free of DM.

Circulating branched-chain amino acids in children with obstructive sleep apnea.

INTRODUCTION: The effects of obstructive sleep apnea (OSA) on the metabolic system are not well understood, especially in children. Recent studies have provided evidence of the modulation of insulin action by branched-chain amino acids (BCAAs) and suggested novel mechanistic relationships between glucose and amino acid metabolic pathways. We hypothesized that plasma BCAA levels may serve as biomarkers of insulin resistance and metabolic dysfunction in children with OSA. METHODS: A polysomnography was conducted for the diagnosis of OSA in 90 snoring children, in a tertiary hospital. Anthropometric and clinical data were measured and venous blood samples were collected for the measurement of plasma glucose, insulin, HbA1c, and amino acids. RESULTS: Children with OSA had significantly higher levels of BCAAs (leucine, isoleucine, and total BCAAs) compared with those without OSA (P = 0.024). A positive significant correlation was observed between insulin levels and both leucine and isoleucine (r = 0.232; P < 0.05). On multivariate regression analyses, the presence of OSA was significantly associated with leucine, isoleucine, and total BCAA concentrations (P = 0.028), whereas the arousal index was associated with leucine, valine, and total BCAA levels (P = 0.037). CONCLUSIONS: The presence of OSA and sleep fragmentation may induce changes in branched-chain amino acid metabolism in snoring children, independently of obesity. These data may suggest a new mechanism linking OSA and glucose homeostasis.

Sex-specific association between serum uric acid and self-reported snoring in rural China: a cross-sectional study.

PURPOSE: Until now, information has been rare on the association of serum uric acid (SUA) with self-reported snoring. Therefore, the purpose of this study was to explore the sex-specific relationship between SUA and self-reported snoring in a general Chinese population. METHODS: A large cross-sectional study of 10,912 participants aged ≥35 years old were recruited from rural areas of Liaoning Province in China during 2012 to 2013. SUA were divided into quartiles separated for males and females. Anthropometric measurements and blood biochemical indexes were examined according to standard protocols. Sleep duration and self-reported snoring status were investigated by trained personnel using a structured questionnaire. RESULTS: The prevalence of self-reported snoring was 37.9% (n = 2197) among females and 47.4% (n = 2420) among males, respectively. The proportion of self-reported snoring presented a significant linear increase across the quartile of SUA level in both sexes. In multivariate logistic regression analysis adjusted for possible confounders, the odds ratio (OR) for SUA with regard to self-reported snoring was significantly higher in females. The OR of self-reported snoring associated with per 1 SD increase in SUA was 1.208 (95%CI 1.118-1.305, P<0.001). The highest quartile of SUA (>293 µmol/L) conferred an independently increased risk for self-reported snoring with OR of 1.643 (95%CI 1.384-1.950, p < 0.001) compared to the lowest quartile of SUA (<209 µmol/L). However, there were no significant relationships between SUA and self-reported snoring among males in all the models. CONCLUSIONS: Our study showed that in rural China, SUA was positively correlated with an increased risk for self-reported snoring in females but not in males. The strong association of SUA levels with self-reported snoring in females emphasizes the necessity of stratifying the sex in investigations of self-reported snoring and encourages exploration of SUA as an effective clinical tool of self-reported snoring risk.

Association between Self-reported Snoring and Prediabetes among Adults Aged 40 Years and Older without Diabetes.

BACKGROUND: Several previous studies have shown that snoring is associated with glucose metabolism and the development of diabetes, but rare study has shown the association between snoring frequency and prediabetes, particularly in China. We hypothesized that individuals who snore might have a higher risk of prediabetes. This study aimed to investigate the association between self-reported snoring and prediabetes in a Chinese population. METHODS: A cross-sectional study was performed in three large communities of Beijing from December 2011 to August 2012 by recruiting individuals aged ≥40 years old. All participants were requested to complete a detailed questionnaire and undergo anthropometric measurements. A 75 g oral glucose tolerance test was performed in individuals without diabetes. Blood samples of all participants were collected; blood glucose and blood fat levels were measured. Multivariate logistic regression models were built to assess the association between snoring frequency and prediabetes. RESULTS: A total of 13,592 participants (female: 66.56%; mean age: 56.8 ± 7.9 years; mean body mass index: 25.5 ± 3.4 kg/m2) were included in the final analysis. Of these, 30.9% were diagnosed with prediabetes, while 41.3% and 25.4% had occasional and habitual snoring, respectively. Habitual snoring was associated with an increased risk of prediabetes (odds ratio [OR]: 1.3, 95% confidence interval [CI]: 1.1-1.4, P< 0.001), after adjusting for diabetes and sleep-related confounders in the multivariable models. Habitual snoring was also associated with isolated impaired fasting glucose (IFG; OR: 1.3, 95% CI: 1.0-1.6; P< 0.001) and isolated impaired glucose tolerance (IGT; OR: 1.3, 95% CI: 1.2-1.5; P< 0.001), but not IFG + IGT (OR: 1.1, 95% CI: 0.9-1.4; P = 0.281). When stratified by total cholesterol (TC) levels, this association between habitual snoring and prediabetes was observed only in individuals with TC <5.6 mmol/L (OR: 1.4, 95% CI: 1.2-1.6; P< 0.001). CONCLUSIONS: Habitual snoring is associated with prediabetes, but only in individuals with TC <5.6 mmol/L. Further prospective studies are needed to confirm this finding.

Metabolic consequences of snoring in adolescents and younger adults: a population study in Chile.

STUDY OBJECTIVES: To investigate the potential association between snoring and other symptoms indicative of sleep-disordered breathing and metabolic syndrome (MetS) in Hispanic adolescents and younger adults using a large population-based survey. METHODS: Sleep-related information, anthropometric measurements and fasting blood samples markers of MetS were obtained from subjects aged 15-40 years collected through the 2nd Chilean Health Survey. Regression models were constructed to evaluate the associations of snoring with MetS, hypertension and serum cholesterol levels. The modulating effect of sleep duration was accounted for in the models. RESULTS: A total of 2147 subjects (42% males, mean age 27.9±7.6 years) were included. Snoring and short sleep duration were present in 43.5 and 25% of the entire population, respectively. MetS was detected in 19.5% of the subjects. In the adjusted regression model, the odds of MetS among snoring subjects were 2.13 times higher (95% confidence interval (CI): 1.52-2.99; P<0.01), and 1.53-fold higher odds of elevated cholesterol also emerged (95% CI: 1.12-2.10; P<0.01). However, the odds of hypertension were not increased by the presence of snoring after adjusting for confounders. In addition, snoring was associated with an increase of 7.26 and 6.56 mg dl-1 for total and low-density lipoprotein cholesterol, respectively, even after adjusting for age, sex and body mass index. Short sleep duration was associated with a small albeit significant risk increase for high systolic blood pressure. CONCLUSIONS: In this large population-based sample of young Hispanic adults and adolescents, snoring, but not sleep duration, emerged as an independent risk factor for dyslipidemia and MetS, but not for hypertension.

The Frequency and Energy of Snoring Sounds Are Associated with Common Carotid Artery Intima-Media Thickness in Obstructive Sleep Apnea Patients.

Obstructive sleep apnea (OSA) is a known risk factor for atherosclerosis. We investigated the association of common carotid artery intima-media thickness (CCA-IMT) with snoring sounds in OSA patients. A total of 30 newly diagnosed OSA patients with no history of cardiovascular diseases were prospectively enrolled for measuring mean CCA-IMT with B-mode ultrasonography, body mass index, metabolic syndrome, 10-year cardiovascular disease risk score, high-sensitivity C-reactive protein, and homocysteine. Good-quality signals of full-night snoring sounds in an ordinary sleep condition obtained from 15 participants were further acoustically analyzed (Included group). All variables of interest were not significantly different (all p > 0.05) between the included and non-included groups except for diastolic blood pressure (p = 0.037). In the included group, CCA-IMT was significantly correlated with snoring sound energies of 0-20 Hz (r = 0.608, p = 0.036) and 652-1500 Hz (r = 0.632, p = 0.027) and was not significantly associated with that of 20-652 Hz (r = 0.366, p = 0.242) after adjustment for age and sex. Our findings suggest that underlying snoring sounds may cause carotid wall thickening and support the large-scale evaluation of snoring sound characters as markers of surveillance and for risk stratification at diagnosis.

Systemic inflammation in patients with compromised upper airway anatomy and primary snoring or mild obstructive sleep apnea.

Our aim was to study associations between serum fibrinogen and C-reactive protein (CRP) levels and respiratory parameters on polysomnography (PSG) in patients with snoring as their main complaint and compromised upper airway anatomy. In this retrospective study, consecutive patients (43 female and 132 male; age range 11-82 years, respiratory distress index-RDI range 0.1-94.4/h) with snoring as their main complaint and compromised upper airway anatomy who underwent PSG were assessed. Spearman's Rho coefficients between RDI, AI (apnea index), hypopnea index (HI), average and lowest SpO2 (in %) and CRP- and fibrinogen serum levels were calculated. Comparisons between groups were made using Wilcoxon-W test. Patients with CRP > 5 mg/dl (22 % of the cohort) had significantly increased RDI, AI, average and lowest SpO2 than patients with CRP < 5 mg/dl. Increased correlation coefficients were observed for average SpO2 (-0.386), RDI (0.355), lowest SpO2 (-0.323) and AI (0.309). Patients with fibrinogen >350 mg/dl (in 33 %) had significantly increased RDI, HI, AI, average and lowest SpO2 than patients with fibrinogen <350 mg/dl. Increased correlation coefficients were found for average (-0.340) and lowest (-0.268) SpO2, RDI (0.236) and AI (0.229). Even patients with RDI < 15/h had increased serum CRP-(in 11 %) and/or fibrinogen-(in 19 %) levels. Simultaneous elevation of both CRP and fibrinogen levels occurred only in patients with RDI > 5/h. Systemic inflammation is strongly associated with average and lowest SpO2, RDI and AI (and with HI) in snorers with compromised upper airway anatomy and is present even in patients with primary snoring and mild obstructive sleep apnea.