Snoring and vascular risk factors and disease in a low-risk Chinese population: the Guangzhou Biobank Cohort Study

Influence of Snoring on the Incidence of Metabolic Syndrome: A Community-Based Prospective Cohort Study in Rural Northeast China

In recent years, there has been an increase in the incidence of metabolic syndrome (MetS) in rural China. Thus, for better intervention, it is necessary to identify the possible risk factors of MetS. This community-based prospective cohort study was performed to evaluate the relationship between the snoring status and incidence of MetS. In this Northeast China rural cardiovascular health study, 4980 residents aged ≥35 years (2586 men and 2394 women; follow-up proportion: 87.5%) at baseline were recruited between 2012 and 2013 and were followed up between 2015 and 2017. The primary outcome was the incidence of MetS, as defined by the unified criteria for MetS defined in 2009. The residents were classified based on their snoring status, and the outcomes were compared between the two groups. The odds ratio (OR) for MetS incidence was estimated using a logistic regression model and adjusted for confounding factors. With a median follow-up duration of 4.6 years, the MetS incidence was higher among the snorers (men, 26.2%; women, 33.5%) than in the non-snorers (men, 19.7%; women, 23.2%). The participants' diastolic blood pressure was increased at follow-up as compared with the baseline values among the male snorers; however, a decrease was noted among the male non-snorers. Similarly, the female snorers had higher blood glucose levels during the follow-up, whereas the non-snorers had lower blood sugar levels. A significant association was noted between snoring and the incidence of MetS (adjusted OR = 1.51; 95% confidence interval = 1.32-1.74). Moreover, the incidence of severe snoring increased with increased levels of snoring, with severe snorers having an OR twice as high as that of the non-snorers (adjusted OR = 2.10; 95% confidence interval = 1.38-3.20). Overall, snoring was independently associated with a higher incidence of newly diagnosed MetS in rural Northeast China. Thus, more attention should be paid to residents with snoring problems.

Impact of Snoring on Telomere Shortening in Adolescents with Atopic Diseases

Atopic diseases can impose a significant burden on children and adolescents. Telomere length is a cellular marker of aging reflecting the impact of cumulative stress exposure on individual health. Since elevated oxidative stress and inflammation burden induced by chronic atopy and snoring may impact telomere length, this study aimed to investigate whether snoring would moderate the relationship between atopic diseases and telomere length in early adolescence. We surveyed 354 adolescents and their parents. Parents reported the adolescents' history of atopic diseases, recent snoring history as well as other family sociodemographic characteristics. Buccal swab samples were also collected from the adolescents for telomere length determination. Independent and combined effects of atopic diseases and snoring on telomere length were examined. Among the surveyed adolescents, 174 were reported by parents to have atopic diseases (20 had asthma, 145 had allergic rhinitis, 53 had eczema, and 25 had food allergy). Shorter TL was found in participants with a history of snoring and atopic diseases (β = -0.34, p = 0.002) particularly for asthma (β = -0.21, p = 0.007) and allergic rhinitis (β = -0.22, p = 0.023). Our findings suggest that snoring in atopic patients has important implications for accelerated telomere shortening. Proper management of atopic symptoms at an early age is important for the alleviation of long-term health consequences at the cellular level.

Associations of snoring frequency with blood pressure among the lean Japanese population: the Toon Health Study

To date, there are few studies in Asian populations on the association between snoring (a major clinical symptom of sleep apnea) and hypertension. This study aims to examine whether snoring frequency is associated with blood pressure and hypertension in the general Japanese population, after adjustment for major confounding factors. A cross-sectional study of 2021 middle-aged Japanese men and women enrolled in the Toon Health Study between 2009-2012 was conducted. Snoring frequency was assessed using a self-reported questionnaire, and was classified into four categories: never, ≤2 times/week, ≥3 times/week, and unknown. Multivariable regression coefficients for each snoring category were calculated for systolic and diastolic blood pressure, and their odds ratios (ORs) and 95% confidence intervals (95% CIs) for hypertension were calculated after adjusting for major confounding factors. The same analyses were also conducted after stratification by several major confounding factors. Multivariable-adjusted means of systolic and diastolic blood pressure among individuals who snored ≥3 times/week were 4.57 mmHg and 2.58 mmHg higher, respectively, than in individuals who never snored (p < 0.05). The multivariable-adjusted OR (95% CI) for hypertension in the group that snored ≥3 times/week was 1.79 (1.29-2.48), compared with the group that never snored. We also found a significant positive association between snoring frequency and hypertension not only in normal and overweight individuals, but also in lean individuals (body mass index ≤22.8 kg/m²). Higher snoring frequency was associated with higher blood pressure and hypertension among both lean and non-lean Japanese.

The Relationship between Simple Snoring and Metabolic Syndrome: A Cross-Sectional Study

PURPOSE

This cross-sectional study was performed to assess the relationship between simple snoring and metabolic syndrome (MetS).

METHODS

A total of 5635 participants including 300 healthy volunteers without snoring allegedly were initially included from 2007 to 2016. Polysomnographic variables, anthropometric measurements, and biochemical indicators were collected. The polynomial linear trend test was used to assess the linear trend across snoring intensity for metabolic score, and logistic regression was used to evaluate the odds ratios (ORs) for MetS after controlling for age, sex, obesity, smoking status, and alcohol consumption.

RESULTS

The final study population consisted of 866 participants. Simple snorers showed more severe metabolic disorders and higher prevalence of MetS than nonsnorers. A significant linear trend was observed between snoring intensity and metabolic score. Simple snoring was significantly associated with increased odds for MetS among all participants (OR = 2.328, 95% CI: 1.340-4.045) and female participants (OR = 2.382, 95% CI: 1.136-4.994) after multivariable adjustment. With regard to MetS components, simple snoring was significantly associated with increased odds for hypertension (OR = 1.730, 95% CI: 1.130-2.650), abdominal obesity (OR = 1.810, 95% CI: 1.063-3.083), and hyper-triglycerides (TG) (OR = 1.814, 95% CI: 1.097-2.998) among all participants, with hypertension (OR = 3.493, 95% CI: 1.748-6.979) among males and with abdominal obesity (OR = 2.306, 95% CI: 1.245-4.270) and hyper-TG (OR = 2.803, 95% CI: 1.146-6.856) among females after multivariable adjustment.

CONCLUSIONS

After excluding the influence of repeated apnea and hypoxia, simple snoring was still significantly associated with MetS, especially in women. Furthermore, the associations were more obvious for hypertension among males and for abdominal obesity and hyper-TG among females. In addition to OSA, simple snoring also should be valued.

Increased risk for new-onset hypertension in midlife male snorers: The 14-year follow-up study

While the association between sleep-related breathing disorders such as snoring and hypertension has been well established, it still remains unclear whether the association differs by age and gender. Therefore, in this 14-year follow-up study, we examined the independent association between self-reported snoring and the incidence of hypertension by gender and age groups in a large cohort of Korean adults. A total of 4,954 adults, aged 40-69 years, free of hypertension at baseline were enrolled. Participants were divided into three groups based on a self-reported snoring frequency: never; occasional (snoring <4 nights per week); and habitual snorer (snoring ≥4 nights). At baseline and biennial follow-up visits, blood pressure was measured by trained examiners. Incident hypertension was defined as the first occurrence at any follow-up examination where the participants had blood pressure ≥140/90 mmHg or were being treated with antihypertensive medication. After adjusting for known cardiovascular risk factors, only in men aged ≤45 years was habitual snoring significantly associated with a 1.5 times higher risk for incident hypertension than never snoring. In this age group, habitual snoring was significantly associated with increased risk for the development of hypertension, regardless of the presence of excessive daytime sleepiness. In women, snoring was not significantly associated with hypertension incidence in any age group. The present study suggests that young male snorers may be at high risk for the future development of hypertension, which has important clinical implications for early detection and treatment of snoring to reduce the burden of cardiovascular disease.

Associations of Sleep Duration and Disturbances With Hypertension in Metropolitan Cities of Delhi, Chennai, and Karachi in South Asia: Cross-Sectional Analysis of the CARRS Study

Objectives

Sleep duration and disturbances may be risk factors for hypertension. Despite the high burden of hypertension in South Asia, little is known about this relationship in this region.

Methods

We analyzed population-level cross-sectional data from the Centre for Cardiometabolic Risk Reduction in South Asia (CARRS) study that recruited representative samples of adults ≥ 20 years from three cities-Delhi, Chennai (India), and Karachi (Pakistan) during 2010-2011. We defined hypertension as self-reported treatment or measured blood pressure (BP) ≥140/90 mm Hg. Data on usual duration of sleep, insomnia, and snoring were collected using "The Sleep Habits Questionnaire" and excessive daytime sleepiness (EDS) using Epworth Sleepiness Score. Logistic and linear regression were done with hypertension and BP as outcome variables, respectively. Age, gender, education, wealth index, family history, and body mass index (BMI) were included as covariates. We used multiple imputation to account for missing variables.

Results

Prevalence of hypertension was 30.1%. The mean (SD) sleep duration was 7.3 (1.2) hours. Insomnia, snoring, and EDS were present in 13.6%, 28.7%, and 4.6%, respectively. Moderate and habitual snoring were associated with increased odds of hypertension (odds ratio [OR] = 1.18, 95% confidence interval [CI] [1.04 to 1.33] and 1.47 [1.29 to 1.67], respectively), after adjusting for covariates. Rare, occasional, and frequent insomnia were associated with increased hypertension (OR 1.41 [1.12 to 1.77], 1.39 [1.16 to 1.67], and 1.34 [1.09 to 1.65], respectively). Sleep duration and EDS were not associated with hypertension.

Conclusion

Self-reported snoring and insomnia were associated with hypertension in South Asia. This relationship needs further exploration through robust longitudinal studies in this region.

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.

The Relationship between Snoring Sound Intensity and Morning Blood Pressure in Workers

STUDY OBJECTIVES

This study aimed to determine the consequences of snoring independent of obstructive sleep apnea (OSA) and hypothesized that snoring sound intensity, as assessed by mean tracheal sound (TS) energy (Leq), is related to morning blood pressure (BP).

METHODS

A home-based TS monitoring study was performed for two nights on 191 workers in Japan using an IC recorder. Leq and the respiratory disturbance index (RDI) were calculated from the TS data. RDI was used as a marker of OSA severity. Systolic and diastolic BP measurements in the evening and morning (eSBP/eDBP and mSBP/mDBP, respectively) were done before and after TS recording. The data of the second night were analyzed.

RESULTS

Leq was significantly related to both mSBP and mDBP (r = 0.32, p < 0.0001; r = 0.34, p < 0.0001, respectively). Leq was also significantly related to morning BP after adjustment for age, sex, and body mass index. However, the relationship was no longer significant when both RDI and Leq were included in the multiple regression model. In non-apneic, non-obese subjects, Leq was significantly related to both mSBP and mDBP (r = 0.38, p < 0.0001; r = 0.33, p = 0.0004, respectively). In this group, Leq was associated with mSBP after adjusting for all confounding factors (n = 106, p = 0.022).

CONCLUSIONS

The association between night TS intensity and morning BP suggests a pathological role of heavy snoring. To understand this association, a prospective cohort study in a general population is warranted.

COMMENTARY

A commentary on this article appears in this issue on page 1581.

Management of severe obstructive sleep apnea using mandibular advancement devices with auto continuous positive airway pressures

The use of continuous positive airway pressures (CPAP) is considered standard treatment of moderate to severe obstructive sleep apnea (OSA). Treatment of the disease poses a great challenge not only for its diagnostic purpose but also for its treatment part. In about 29-83% of the patients, treatment is difficult because of non-compliance resulting due to high pressures, air leaks and other related issues. In such situations, alternative methods of treatment need to be looked for so as to ascertain better management. Mandibular advancement devices along with CPAP may show better treatment outcome in specific situations.

Glycaemia is associated with cognitive impairment in older adults: the Guangzhou Biobank Cohort Study

AIMS

an association between T2DM and cognitive impairment has been reported among Western populations, but data are limited in other settings. We investigated the cross-sectional association between fasting blood glucose (FBG) and cognition in an older Chinese population.

METHODS

the Guangzhou Biobank Cohort Study included 27,971 individuals (50-96 years, mean age 61.5 years, 72% female) with measures of cognitive function assessed using modified Delayed Word Recall Test (DWRT) and Mini-Mental State Examination (MMSE). Fasting glucose and lipids, and potential confounders were measured.

RESULTS

after adjustment for potential confounders, the risk for cognitive impairment as measured by DWRT, significantly increased [odds ratio (OR) = 1.18, 95% CI 1.00-1.40] but the association was of borderline significance when measured by MMSE (OR = 1.04, 95% CI 0.73-1.47) in those with diabetes relative to those without diabetes. Fasting blood glucose was significantly negatively associated with cognitive function as measured by DWRT but not MMSE, with an increase of 1 mmol/l of FBG associated with a decrease of 0.02 in DWRT (P < 0.05, 95% CI -0.03 to -0.002) and 0.03 in MMSE score (P = 0.114, 95% CI -0.06-0.01).

CONCLUSIONS

an FBG level indicative of T2DM was associated with increased risk for cognitive impairment. The findings also demonstrate that glycaemia is continuously associated with cognitive impairment, suggesting that dysfunction is associated with increasing glucose levels even in the normoglycaemic range.

Mean tracheal sound energy during sleep is related to daytime blood pressure

STUDY OBJECTIVES

The pathological role of snoring independent of obstructive sleep apnea remains under debate. The authors hypothesized that snoring sound intensity, as assessed by mean tracheal sound energy (Leq) during sleep, is related to daytime blood pressure.

DESIGN

Retrospective analysis of clinical records and polysomnography data.

SETTING

Sleep laboratory at a national hospital in Japan.

PATIENTS

Consecutive patients who underwent diagnostic polysomnography with suspicion of sleep apnea between January 2005 and December 2009 (n = 1,118).

INTERVENTIONS

Not applicable.

MEASUREMENTS AND RESULTS

Leq was calculated from tracheal sound spectra recorded every 0.2 sec during polysomnography. Daytime high blood pressure (HBP) was defined as taking antihypertensive drugs or having a systolic blood pressure ≥ 140 mm Hg or a diastolic blood pressure ≥ 90 mmHg at the patient's first clinical visit. Patient age, sex, body mass index, apnea-hypopnea index, alcohol consumption, and smoking were considered as confounders. Leq during sleep was associated with HBP after adjusting for all confounding factors (n = 1,074, P = 0.00019). This association was demonstrated even in nonapneic nonobese patients (n = 232, P = 0.012).

CONCLUSIONS

The association between snoring intensity, as assessed by mean sound energy, and blood pressure suggests a pathological role for heavy snoring. Further study in a general population is warranted.

Influence of heart rate at rest for predicting the metabolic syndrome in older Chinese adults

The aim of this study was to examine the relationship between seated resting heart rate and the metabolic syndrome (MetS) among older residents of Guangzhou, South China. A total of 30,519 older participants (≥50 years) from the Guangzhou Biobank Cohort Study were stratified into quartiles based on seated resting heart rate. The associations between each quartile and the MetS were assessed using multivariable logistic regression. A total of 6,907 (22.8 %) individuals were diagnosed as having the MetS, which was significantly associated with increasing heart rate quartiles (P < 0.001). Participants in the uppermost quartile (mean resting heart rate 91 ± 8 beats/min) of this cardiovascular proxy had an almost twofold increased adjusted risk (odds ratio (95 % CI) = 1.94 (1.79, 2.11), P < 0.001) for the MetS, as compared to those in the lowest quartile (mean resting heart rate, 63 ± 4 beats/min). Heart rate, which is an inexpensive and simple clinical measure, was independently associated with the MetS in older Chinese adults. We hope these observations will spur further studies to examine the usefulness of resting heart rate as a means of risk stratification in such populations, for which targeted interventions should be implemented.

Association between self reported snoring, STOP questionnaire and postoperative pulmonary complications in patients submitted to ortophaedic surgery

Background

Obstructive sleep apnea (OSA) may increase perioperative complications. The aim of this study was to determine the relationship among postoperative pulmonary complication, snoring and STOP questionnaire in patients with ortophaedic surgery.

Methods

1,406 consecutive records of patients who had undergone elective ortophaedic surgery during the period January 2005-December 2008 were investigated retrospectively. Demographic information, sleep symptoms, STOP questionnaire, comorbidities and outcome data were collected.

Results

There were 289 (20.5%) snorers and 1,117 (79.5%) non-snorers in the study group. There was no significant difference between snorer and non-snorer patients (p > 0.05) in the prevalence of pneumonia and respiratory failure. But in snorer patients the rate of postoperative atelectasis was significantly higher than in non-snorer group (p < 0.0001). The STOP Questionnaire was given to 1,406 patients and 147 (10.4%) out of them were classified at high risk of OSA. There was no significant difference in the prevalence of pneumonia and respiratory failure between low and high risk group (p > 0.05). However, in high risk patients the occurrence of postoperative atelectasis was significantly higher than in low risk group (p < 0.0001).

Conclusion

Postoperative atelectasis was significantly more prevalent in the high risk group according to STOP questionnaire.

Prevalence of sleep abnormalities and their association among hypothyroid patients in an Indian population

OBJECTIVE

To estimate the prevalence of sleep abnormalities and their association with hypothyroidism and metabolic risk factors in a relatively lean urban South Indian population.

METHODS

This population-based, cross-sectional study was carried out in the urban population of Chennai, one of the largest metropolitan cities of India. Phase 1 was conducted in the field and involved a door-to-door survey of 26,000 individuals. In phase 2, every tenth subject recruited in phase 1 (n=2600) was invited to our centre for detailed anthropometric and biochemical measurements. For the current study, a subset of 358 subjects with positive family history of hypothyroidism was randomly selected. A validated questionnaire assessing various sleep abnormalities (snoring, daytime sleepiness, lack of refreshing sleep and number of hours of sleep) was administered. Anthropometric and biochemical measurements were obtained to assess metabolic risk factors including thyroid status.

RESULTS

Snorers were more often male, older, smokers and had higher BMI, neck circumference, blood pressures, and hypothyroidism. Out of 358 patients, 133 had impaired thyroid function (37.1%) and 64 patients had both snoring and impaired thyroid function (17.8%). Subjects with daytime sleepiness had higher BMI and neck obesity. The overall prevalence of snoring and daytime sleepiness was 52% and 64%, respectively. Both sleep measures were associated with hypothyroid status. Metabolic syndrome was significantly associated with snoring even after adjusting for age, sex, family history of hypothyroidism, physical activity, smoking and alcohol.

CONCLUSIONS

The prevalence of snoring and daytime sleepiness is high among urban South Indians who are relatively lean. Both disorders are associated with hypothyroidism, although these associations were stronger in those with obesity. Based on our case prevalence and the other reports cited previously, we can reasonably conclude that thyroid screening of sleep clinic patients is essential.

Medical disorders impacted by obstructive sleep apnea

Normal-sleeping individuals experience a lower metabolic rate and relative cardiovascular quiescent state with lower heart rate and blood pressure that naturally occurs during sleep compared with the waking state. In patients with obstructive sleep apnea (OSA), this quiescent state becomes disrupted. Research has shown a higher risk for several medical disorders, most ominous being a myocardial infarction or stroke. This article serves as an overview to the cardiovascular, cerebrovascular, metabolic, and gastroesophageal effects of OSA.

Snoring, inflammatory markers, adipokines and metabolic syndrome in apparently healthy Chinese

OBJECTIVE

Chronic low-grade inflammation and adipokines dysregulation are linked to mechanisms underscoring the pathogenesis of obesity-related metabolic disorders. Little is known about roles of these cytokines on the association between snoring and metabolic syndrome (MetS). We aimed to investigate whether a cluster of cytokines are related to snoring frequency and its association with MetS in apparently healthy Chinese.

METHODS

Current analyses used a population-based sample including 1059 Shanghai residents aged 35-54 years. Self-reported snoring frequency was classified as never, occasionally and regularly. Fasting plasma glucose, lipid profile, insulin, C-reactive protein, interleukin-6, interleukin-18, lipopolysaccharide binding protein, high-molecular-weight adiponectin and leptin were measured. MetS was defined by the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian-Americans.

RESULTS

Overweight/obese subjects had significantly higher prevalence of regular snorers than their normal-weight counterparts (34.8% vs. 11.5%, P<0.001). Regular snoring was associated with unfavorable profile of inflammatory markers and adipokines. However, those associations were abolished after adjustment for body mass index (BMI) or waist circumference. The MetS risk (multivariate-adjusted odds ratio 5.41, 95% confidence interval 3.72-7.88) was substantially higher in regular snorers compared with non-snorers. Controlling for BMI remarkably attenuated the association (2.03, 1.26-3.26), while adjusting for inflammatory markers and adipokines showed little effects.

CONCLUSION

Frequent snoring was associated with an elevated MetS risk independent of lifestyle factors, adiposity, inflammatory markers and adipokines in apparently healthy Chinese. Whether snoring pattern is an economic and no-invasive indicator for screening high-risk persons needs to be addressed prospectively.

The utility of collaborative biobanks for cardiovascular research

Differences between animal and human atherosclerosis have led to the requirement for clinical data, imaging information and biological material from large numbers of patients and healthy persons. Where such "biobanks" exist, they have been fruitful sources for genomewide association, diagnostic accuracy, ethnicity, and risk stratification cohort studies. In addition once established, they attract funding for future projects. Biobanks require a network of medical contributors, secure storage facilities, bioinformatics expertise, database managers, and ethical working practices to function optimally. There is the opportunity for collaboration between individual biobanks to further amplify the advantages afforded.

Repeating administration of Epworth Sleepiness Scale is clinically useful

PURPOSE

We aimed to verify whether it is clinically useful to repeat the Epworth Sleepiness Scale (ESS) in individuals with suspected sleep-disordered breathing (SDB).

METHODS

In this cross-sectional, prospective study, results of the repeated administration of the ESS were analyzed. In 929 consecutive patients, ESS was obtained as usual in the laboratory routine, immediately before the sleep study (ESS1) and was repeated in the morning, after the polysomnography (ESS2). ROC curve, classical psychometry, and item response theory (IRT) Rasch analysis were used to assess measurement properties of ESS.

RESULTS

The ESS1 score was (mean ± SD), 11 ± 5.1, and the ESS2, 13 ± 4.7 (p < 0.001). Change in ESS score is explained in multivariate analysis by age, but not by gender, educational level, change in Stanford Sleepiness Scale, symptoms of sleep disorder, or polysomnography results. Accuracy of an ESS score >10 to predict apnea-hypopnea index ≥5 increased from 56% (ESS1) to 72% (ESS2). IRT psychometric properties (unidimensionality, invariance, local independence) were maintained in ESS2.

CONCLUSIONS

Repeating the administration of the Epworth Sleepiness Scale in a clinical setting increases its score and diagnostic accuracy and correlation with SDB variables, without changing the psychometric properties of the scale. This experiment indicates the clinical usefulness of repeating the ESS. The scale can be repeated at a negligible cost, before dismissing individual patients on the basis of a low ESS score, discontinuing a potentially lifesaving diagnostic and therapeutic process.

Prevalence of sleep abnormalities and their association with metabolic syndrome among Asian Indians: Chennai Urban Rural Epidemiology Study (CURES-67)

OBJECTIVE

To estimate the prevalence of sleep abnormalities and their association with glucose intolerance and metabolic syndrome (MS) in the normal-weight urban South Indian population.

METHODS

This population-based, cross-sectional study was carried out in 358 subjects aged 20-76 years randomly selected from the Chennai Urban Rural Epidemiology Study in South India. A validated questionnaire assessing various sleep abnormalities (snoring, daytime sleepiness, lack of refreshing sleep, and number of hours of sleep) was administered. All subjects underwent an oral glucose tolerance test, and anthropometric biochemical measurements were obtained to assess cardiometabolic risk factors including glucose intolerance. Diabetes risk was assessed using a previously validated Indian Diabetes Risk Score (IDRS).

RESULTS

The overall prevalence of snoring and daytime sleepiness was 40% and 59%, respectively. Snorers were more male, older, smokers, and had higher levels of cardiometabolic risk factors. Subjects with daytime sleepiness had higher body mass index (BMI) and abdominal obesity. Both snoring (50.9% vs 30.2%, p<0.001) and daytime sleepiness (68% vs 49.7%, p<0.001) were more prevalent among subjects with impaired glucose metabolism compared to those with normal glucose metabolism. Both sleep measures were associated with higher diabetes risk scores, as assessed by the IDRS (snoring: trend χ2, 11.14, p=0.001; daytime sleepiness: trend χ2, 5.12, p=0.024). Metabolic syndrome was significantly associated with snoring even after adjusting for age, sex, family history of diabetes, physical activity, smoking, and alcohol.

CONCLUSIONS

The prevalence of snoring and daytime sleepiness is high among urban South Indians and these two sleep measures are associated with glucose intolerance, MS, and higher diabetes risk scores.

Smoking and sleep disorders in Chinese adolescents

OBJECTIVE

To investigate the association between adolescent smoking and sleep disorders.

METHODS

In the Hong Kong student obesity surveillance project, 29,397 Chinese students, aged 12-18 years, completed a health survey. Insomnia was defined as having any of the following three symptoms: difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS) and early morning awakening (EMA). The presence of snoring and difficulty breathing during sleep (DBS) was also reported. Logistic regression yielded adjusted odds ratios (ORs) for each sleep disorder by smoking status.

RESULTS

Compared with never smokers, the ORs (95% CI) of insomnia were 1.39 (1.25-1.54) for experimenters (smoked once or a few times) and 0.91 (0.83-1.00) for current smokers. The corresponding ORs were 1.42 (1.16-1.74) and 3.58 (3.15-4.06) for snoring (P for trend<0.001) and 1.40 (1.10-1.79) and 3.39 (2.97-4.03) for DBS (P for trend<0.001). Current smokers compared with never smokers were less likely to report DIS (OR=0.43, 95% CI=0.38-0.50, P<0.001) and EMA (OR=0.83, 95% CI=0.73-0.94, P=0.003), but more likely to report DMS (OR=1.45, 95% CI=1.28-1.63, P<0.001).

CONCLUSIONS

In terms of dosage, adolescent smoking was associated with snoring and DBS, with increasing ORs from never smokers to experimental and current smokers. Current smoking was associated positively with DMS, but negatively with DIS and EMA.

Síndrome das apnéias-hipopnéias obstrutivas do sono: associação com gênero e obesidade e fatores relacionados à sonolência

OBJETIVO: Estudar os efeitos de gênero e obesidade e identificar fatores relacionados à sonolência diurna excessiva (SDE) em indivíduos com síndrome das apnéias-hipopnéias obstrutivas do sono (SAHOS). MÉTODOS: Foram selecionados para inclusão no estudo 300 pacientes consecutivos, atendidos em clínica do sono, com índice de apnéia/hipopnéia (IAH) > 10 eventos/hora de sono, que completaram adequadamente a avaliação clínica. RESULTADOS: A média de idade foi de 47 ± 11 anos e o IAH médio foi de 52,1 ± 29,2 eventos/hora de sono. As mulheres apresentaram maior média de idade, menos sonolência e menos tempo em apnéia. O escore médio de SDE foi de 14,7 ± 7,2. O escore de SDE correlacionou-se melhor com movimentos corpóreos (r = 0,43; p < 0,01), eventos respiratórios durante o sono (r = 0,40; p < 0,01), tempo em apnéia (r = 0,40; p < 0,01), valores mínimos da saturação periférica de oxigênio (SpO2; r = -0,38; p < 0,01) e IAH (r = 0,37; p < 0,01). O índice de massa corpórea (IMC) médio foi de 30,2 ± 5,3 kg/m². Sobrepeso, obesidade e obesidade mórbida foram observados em, respectivamente, 41, 44 e 5,3% dos casos. A gravidade da doença correlacionou-se melhor com IMC (r = 0,51; p < 0,01). CONCLUSÕES: Maior média de idade, menor escore de SDE e menor tempo em apnéia foram associados ao gênero feminino. Fragmentação do sono, número e duração de eventos respiratórios durante o sono, níveis de SpO2 e obesidade se associaram à sonolência. O IMC teve efeito significativo na gravidade da SAHOS.

Obstructive sleep apnea and type 2 diabetes: interacting epidemics

Type 2 diabetes is a major public health concern with high morbidity, mortality, and health-care costs. Recent reports have indicated that the majority of patients with type 2 diabetes also have obstructive sleep apnea (OSA). There is compelling evidence that OSA is a significant risk factor for cardiovascular disease and mortality. Rapidly accumulating data from both epidemiologic and clinical studies suggest that OSA is also independently associated with alterations in glucose metabolism and places patients at an increased risk of the development of type 2 diabetes. Experimental studies in humans and animals have demonstrated that intermittent hypoxia and reduced sleep duration due to sleep fragmentation, as occur in OSA, exert adverse effects on glucose metabolism. Based on the current evidence, clinicians need to address the risk of OSA in patients with type 2 diabetes and, conversely, evaluate the presence of type 2 diabetes in patients with OSA. Clearly, there is a need for further research, using well-designed studies and long-term follow-up, to fully demonstrate a causal role for OSA in the development and severity of type 2 diabetes. In particular, future studies must carefully consider the confounding effects of central obesity in examining the link between OSA and alterations in glucose metabolism. The interactions among the rising epidemics of obesity, OSA, and type 2 diabetes are likely to be complex and involve multiple pathways. A better understanding of the relationship between OSA and type 2 diabetes may have important public health implications.

Smoking, smoking cessation and aortic arch calcification in older Chinese: the Guangzhou Biobank Cohort Study

OBJECTIVE

To study the association between smoking, smoking cessation and aortic arc calcification (AAC) in an older Chinese population.

METHODS

A total of 3022 men and 7279 women aged 50-85 years were recruited and received a medical check-up including measurement of fasting plasma vascular risk factors. Two radiologists reviewed the posterior-anterior plain chest X-ray radiographs and assessed AAC together. Information on smoking status, socioeconomic and lifestyle factors was collected.

RESULTS

The crude prevalence of AAC in men (38.58%) was lower than that in women (41.37%). The adjusted odds ratios of AAC increased significantly across never, ex- and current smokers in both genders. Dose-response relationships were observed among current smokers for smoking amount (cigarettes/day), smoking duration (years) and cigarette pack-years in both genders (all p<0.01). The odds ratios decreased significantly (p=0.018) with longer duration of quitting in light ex-smoking men (<23.5 pack-years) but showed no beneficial effect (p=0.72) for heavy ex-smokers (>or=23.5 pack-years).

CONCLUSION

Smoking increased the risk of AAC in Chinese, while smoking cessation decreased the risk only in male light ex-smokers. Chest X-ray is a cheap and simple method to detect AAC, which should be an important warning signal for immediate smoking cessation.

Implications of increased weight and waist circumference on vascular risk in an older Chinese population: the Guangzhou Biobank Cohort Study

BACKGROUND

The relationships between weight and waist on vascular risk are well described, but the long-term impact of these parameters is less clearly defined, particularly in Chinese populations.

METHODS

Ten thousand four hundred and ten older subjects (50-85 years) were recruited and blood pressure, anthropometric, and fasting vascular risk factors measured. Socioeconomic and demographic data, including self-reported weight and waist gain since 18 years. The association of weight and waist gain with these vascular risk factors was analysed.

RESULTS

Weight, and particularly waist gain were associated with a more adverse vascular risk factor profile, with the most adverse profile associated with gains in both weight and waist. Anthropometric gains were associated with increased risk even in non-obese subjects (p<0.05). Even after adjustment for a range of demographic and socioeconomic factors, waist gain was associated with additional risk of having the metabolic syndrome and its components and self-reported vascular disease in those centrally obese subjects (p<0.05 for all).

CONCLUSION

Increased weight and waist increased the level of vascular risk factors and self-reported disease in both non-obese and obese subjects. The high prevalence of vascular risk factors in this population forewarns of a major developing health burden in the rapidly modernising 1.2 billion Chinese population.