Relation of habitual snoring with components of metabolic syndrome in Korean adults

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

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.

Association between self-reported snoring and metabolic-associated fatty liver disease: A cross-sectional analysis of the NHANES 2017-2018

BACKGROUND

Snoring may play an important role in a variety of diseases, especially metabolic diseases. However, there are no reports on the relationship between snoring and the risk of metabolic-associated fatty liver disease (MAFLD). This study aimed to investigate the association between snoring and MAFLD.

METHODS

A cross-sectional analysis was performed based on the National Health and Nutrition Examination Survey (NHANES) 2017-2018. Self-reported snoring frequency was grouped into four categories (never, rarely, occasionally, and frequently). MAFLD was diagnosed based on the evidence of hepatic steatosis and any of the following three conditions: overweight/obesity, diabetes mellitus or metabolic dysfunction. Logistic regression with sampling weights was used to examine the association between snoring and MAFLD.

RESULTS

A total of 5016 patients were included, and 50.14% of individuals had MAFLD. Compared with nonsnorers, those who snored frequently were associated with increased odds for MAFLD (odds ratio (OR): 1.376, 95% confidence interval (CI): 1.122-1.688, p trend <0.001). The subgroup analyses suggested that no significant interactions were found between snoring and other potential effect modifiers, including age, sex, body mass index (BMI), smoking status, chronic obstructive pulmonary disease (COPD) and hypertension.

CONCLUSION

Snoring was independently and positively associated with a higher prevalence of MAFLD, suggesting that attention to snoring may contribute to the early detection of MAFLD.

Association Between Self-Reported Snoring and Metabolic Syndrome: A Systematic Review and Meta-Analysis

Background: Snoring is a common condition. Previous studies have reported the relationships between snoring and metabolic syndrome (MetS) and/or its five components: hypertension, hyperglycemia, low-high density lipoprotein (low-HDL), high-triglyceride level, and abdominal obesity. However, conclusions have been inconsistent, and there has been no comprehensive summary on this. Therefore, we performed a systematic review on the relationships between snoring and MetS, including each of MetS' components.

Methods: A systematic review and a meta-analysis were conducted following the Meta-analysis of Observational Studies in Epidemiology group and Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. Electronic databases including PubMed, Embase, and the Cochrane Library were searched for publications from inception to 15 July 2020. The inverse-variance weighted method was used in the meta-analysis to calculate the pooled odds ratios (ORs) and their 95% confidence intervals (CIs) to determine the association between snoring and MetS (and its components) through a fixed or random effect model. A restricted cubic spline regression model and the linear regression model were used in a two-stage dose–response meta-analysis to evaluate the non-linear and the linear trends between snoring frequency and MetS and its components.

Results: A total of 40 studies with 966,652 participants were included in this study. The pooled ORs between snoring and MetS and its components, hypertension, hyperglycemia, low-HDL, high-triglyceride level, and abdominal obesity, were 1.61 (95% CI, 1.43–1.78), 1.23 (95% CI, 1.15–1.31), 1.05 (95% CI, 1.04–1.07), 1.09 (95% CI, 1.00–1.18), 1.08 (95% CI, 1.00–1.17), and 1.75 (95% CI, 1.46–2.05), respectively. Non-linear trends were detected in the five associations except for low-HDL. A linear trend was detected in the association of snoring with hypertension, hyperglycemia, low-HDL, or abdominal obesity, with ORs of 1.07 (95% CI, 1.01–1.13), 1.05 (95% CI, 1.02–1.08), 1.03 (95% CI, 1.02–1.04), and 1.17 (95% CI, 1.16–2.89), respectively.

Conclusion: Snoring was a risk factor of MetS, and a dose–response relationship existed between the two. Timely intervention in identifying snorers can minimize as much as possible the risk of metabolic syndrome in those who snore.

Additive interaction of snoring and body mass index on the prevalence of metabolic syndrome among Chinese coal mine employees: a cross-sectional study

BACKGROUND

Although snoring has been previously reported to be associated with metabolic syndrome (MetS), its interaction with body mass index(BMI) on MetS remains unclear. We aimed to examine the individual effects and possible interaction between snoring and BMI on MetS.

METHODS

From July 2013 to December 2013, 3794 employees of coal mining enterprises aged 18 to 65 were recruited from Shanxi province of China. The individual effects were assessed by multivariable logistic regression model. Additive interaction was evaluated by calculating the relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP) and synergy index(S).

RESULTS

We found that, after adjusting for potential confounders, odds ratio (OR) and 95% CI for MetS was 1.30 (1.09, 1.56) in occasional snorers and 1.50 (1.24, 1.82) in habitual snorers compared with non-snorers. BMI ≥ 24 was related to high risk of MetS (OR, 3.27; 95% CI, 2.93-3.63). Significant additive interaction between snoring and BMI on MetS was detected. The estimates and 95% CI of the RERI, AP and S were 1.89 (0.67, 3.24), 0.23 (0.08, 0.38), and 1.37 (1.11, 1.75), respectively. However, stratified by workplace, the additive interaction was only significant among underground front-line and ground workers.

CONCLUSIONS

Both Snoring and BMI were related to high risk of Mets. Moreover, there are additive interaction between snoring and BMI. Snorers who worked underground front-line and ground are more susceptible to the negative impact of being overweight on MetS.

Self-reported snoring is associated with chronic kidney disease independent of metabolic syndrome in middle-aged and elderly Chinese

AIMS/INTRODUCTION

To investigate the correlation between snoring and chronic kidney disease (CKD), and explore whether metabolic syndrome (MetS) plays an important role in this relationship among middle-aged and elderly Chinese.

MATERIALS AND METHODS

The participants included in the present study were categorized into three subgroups based on self-reported snoring frequency (regularly [≥3 times per week], occasionally [between 'regularly' and 'never'] or never [<1 time per month]). An estimated glomerular filtration rate <60 mL/min/1.73 m2 was considered as CKD. We diagnosed MetS based on the 2004 Chinese Diabetes Society criteria. We explored the relationship between snoring and CKD by using multiple logistic regressions.

RESULTS

The frequency of MetS, MetS components and CKD was dramatically higher in regular snorers than in non-snorers and occasional snorers. The odds ratios for MetS and all the MetS elements, except for hyperglycemia, increased progressively with the snoring frequency (P < 0.001). Upon additional adjustment for other MetS components, snoring was not significantly related with hypertension; however, the associations between snoring frequency and overweight/obesity and dyslipidemia became attenuated, but still remained statistically significant (P < 0.01). Interestingly, odds ratios for CKD also increasingly augmented with snoring frequency (P < 0.001). Upon further adjustment for individual MetS components or MetS, regular snoring also resulted in a significantly increased odds ratio for CKD (odds ratio 1.72; P = 0.034) relative to non-snoring.

CONCLUSIONS

Self-reported snoring is closely associated with CKD independent of MetS among middle-aged and elderly Chinese.

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.

The symptoms and risk of sleep apnea among adults in the United Arab Emirates

INTRODUCTION:

Recently, sleeping disorders and snoring are being recognized as a public health concern with various risk factors and health consequences. The main objective of the present study was to determine the prevalence of snoring and sleep apnea among adults (20–60 years) in Sharjah (United Arab Emirates, UAE) and assess the major risk factors as well as the general knowledge among the population.

METHODS:

A self-administrated Questionnaire of five sections including both Berlin questionnaire (BQ) and the Epworth Sleepiness Scales (ESS) were given to a randomly selected population in Sharjah between the ages of 20–60 years. Data were analyzed using SPSS software version 22.0.

RESULTS:

Nearly 34.2% of the study population reported to be snorers, and 43.2% of snorers were at high risk of sleep apnea based on the BQ. Gender was significantly associated with snoring (P = 0.038), as 40.8% of males reported snoring compared to 28.7% of females. Elderlies (50–60 years) were at a higher risk, and obesity (body mass index >30) was considered to be a powerful risk factor as 46.8% of the obese participants reported snoring. Those who scored higher on the ESS were more likely to be snorers (P = 0.001) and were likely to fall into the high-risk category in the BQ (P = 0.007). In addition, smoking (P = 0.005), hypertension (P = 0.005), and nasal septal deviation (P = 0.024) were also considered as risk factors.

CONCLUSION:

Prevalence and major risk factors within the UAE are similar to those in other countries. Sleeping disorders and snoring campaigns and management facilities should be considered to raise the awareness about these issues and manage their risk factors.

Frequency of Loud Snoring and Metabolic Syndrome among Korean Adults: Results from the Health Examinees (HEXA) Study

Studies regarding the association between snoring and metabolic abnormalities have been inconsistent. We examine whether snoring frequency and obstructive sleep apnea markers are associated with metabolic syndrome (MetS) among Koreans aged 40-69 years. A total of 72,885 subjects (24,856 men, 48,029 women) from the Health Examinees Gem study between 2009 and 2013 were included. Snoring frequency was grouped into five categories (never, 1-3/month, 1-3/week, 4-5/week, 6+/week). Obstructive sleep apnea markers included breathing interruptions and awakenings. Adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated through logistic regression. Compared with non-snorers, those who snore 6+/week were associated with increased odds for MetS (OR: 2.07, 95% CI: 1.91-2.25, p-trend < 0.0001 among men; OR: 1.45, CI: 1.33-1.58, p-trend < 0.0001 among women). Snoring frequency is associated with MetS and its components in both men and women. Snoring and obstructive sleep apnea markers are important indicators of sleep quality, which may facilitate early detection of sleep disorders and further complications such as MetS.

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.

Plasma isoflavone concentration is associated with decreased risk of type 2 diabetes in Korean women but not men: results from the Korean Genome and Epidemiology Study

AIMS/HYPOTHESIS

To examine the association between soybean products and risk of type 2 diabetes, we measured four isoflavone biological markers--genistein, daidzein, glycitein and equol--in a nested case-control study.

METHODS

The study population was composed of 693 cases (316 women and 377 men) and 698 matched controls (317 women and 381 men) within the Korean Genome and Epidemiology Study. The concentrations of isoflavone biomarkers were measured using HPLC-MS/MS on plasma samples that were collected at baseline. A stratified analysis was undertaken to examine the association between plasma isoflavone concentrations and risk of type 2 diabetes according to sex and equol production. Logistic regression models were used to compute ORs and 95% CIs adjusted for confounders.

RESULTS

In women, compared with the lowest quartile of plasma concentration of genistein, the highest quartile exhibited a significantly decreased risk of diabetes (OR 0.58, 95% CI 0.35, 0.95). When stratified by equol-producing status in women, the OR for diabetes in the highest vs the lowest quartile of genistein concentration was 0.31 (95% CI 0.16, 0.60) in equol producers, but genistein concentration was not associated with risk of diabetes in equol non-producers (p for interaction = 0.013). In men, isoflavone concentrations were not associated with risk of diabetes, regardless of equol-producing status.

CONCLUSIONS/INTERPRETATION

High plasma concentrations of genistein were associated with a decreased risk of type 2 diabetes in women. This inverse association was prominent in equol-producing participants. These results suggest a beneficial effect of a high intake of soybean products on risk of type 2 diabetes in women.

Simple snoring: not quite so simple after all?

Simple snoring (SS), in the absence of obstructive sleep apnoea (OSA), is a common problem, yet our understanding of its causes and consequences is incomplete. Our understanding is blurred by the lack of consistency in the definition of snoring, methods of assessment, and degree of concomitant complaints. Further, it remains contentious whether SS is independently associated with daytime sleepiness, or adverse health outcomes including cardiovascular disease and metabolic syndrome. Regardless of this lack of clarity, it is likely that SS exists on one end of a continuum, with OSA at its polar end. This possibility highlights the necessity of considering an otherwise 'annoying' complaint, as a serious risk factor for the development and progression of sleep apnoea, and consequent poor health outcomes. In this review, we: 1) highlight variation in prevalence estimates of snoring; 2) review the literature surrounding the distinctions between SS, upper airway resistance syndrome (UARS) and OSA; 3) present the risk factors for SS, in as far as it is distinguishable from UARS and OSA; and 4) describe common correlates of snoring, including cardiovascular disease, metabolic syndrome, and daytime sleepiness.

Self-reported snoring and metabolic syndrome: the Korean Multi-Rural Communities Cohort Study

PURPOSE

We investigated the association between self-reported snoring and metabolic syndrome (MetS) and its components among a community-dwelling Korean population.

METHODS

A total of 7,038 subjects participated in the Korean Multi-Rural Communities Cohort Study between January 2005 and February 2010 and were included in the analysis. Frequency of snoring was classified into never, rarely (<1 day/week), occasionally (1-3 days/week), and habitually (≥4 days/week).

RESULTS

In the fully adjusted model, compared to non-snorers, the odds ratio (OR) for MetS of snorers was significantly higher in subjects with rare snoring (OR, 1.42; 95% confidence interval (CI), 1.23-1.64), occasional snoring (OR, 1.79; 95% CI, 1.55-2.07), and habitual snoring (OR, 2.03; 95% CI, 1.77-2.33) than those who did not snore. The ORs for abdominal obesity were significantly higher in rare snoring subjects (OR, 1.51; 95% CI, 1.30-1.75), occasional snoring (OR, 1.71; 95% CI, 1.47-1.98), and habitual snoring (OR, 2.07; 95% CI, 1.80-2.38) than in non-snorers after adjusting for covariates.

CONCLUSIONS

Snoring was significantly and linearly associated with MetS, and this association was consistently present in both sexes. Positive and graded associations were observed between snoring frequency and MetS components including high blood pressure, elevated fasting glucose levels, and abdominal obesity, independent of conventional risk factors and other MetS components.

Prospective study of optimal obesity index cutoffs for predicting development of multiple metabolic risk factors: the Korean genome and epidemiology study

BACKGROUND

In this prospective cohort study, we estimated the risk of developing more than 1 metabolic risk factor, using different obesity indices. In addition, we investigated the relative usefulness of the obesity indices for predicting development of such risk factors and calculated optimal cutoffs for the obesity indices.

METHODS

The cohort comprised 10 038 representative residents of a small city and a rural county who were recruited in 2001-2002. Follow-up examinations were conducted every 2 years. Among the 3857 participants without metabolic syndrome at baseline, 1102 new cases occurred during the 6-year follow-up. Receiver operating characteristic (ROC) curves for the obesity indices were plotted to compare the usefulness of the obesity indices.

RESULTS

The numbers of new cases of multiple metabolic risk factors among people in the highest quintiles of body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR), and waist-height ratio at the baseline examination were 2 to 3 times those in the lowest quintiles. The area under the ROC curve for WHR was significantly higher than that for BMI. The optimal BMI cutoff was 24 kg/m(2) in men and women, and the optimal WC cutoffs were 80 cm and 78 cm in men and women, respectively.

CONCLUSIONS

Both overall obesity and central obesity predicted risk of developing multiple metabolic risk factors, and WHR appeared to be a better discriminator than BMI. To prevent development of metabolic diseases among Koreans, it might be useful to lower the cutoff for abdominal obesity, as defined by WC.

Obstructive sleep apnea and the metabolic syndrome

Obstructive sleep apnea (OSA) and the metabolic syndrome have a strong association with each other owing to their common feature of obesity, but an association independent of obesity has been demonstrated in several studies. There is also evidence, of varying strengths, from epidemiologic and clinical studies, for the independent association between OSA and individual core components of the metabolic syndrome, including hypertension, insulin resistance and dyslipidemia. To date, the data are strongest for hypertension, while data for adverse glucose or lipid metabolism are more controversial. Obesity and other factors, such as alcohol drinking and smoking, obviously pose major confounding hurdles to the clarification of the causal or aggravational role of OSA on cardiometabolic risks. Recurrent episodes of obstructed breathing notably result in intermittent hypoxemia and sleep fragmentation, and these may in turn lead to many adverse body responses, including sympathetic activation, neurohumeral changes and inflammation, which are the seeds for cardiometabolic dysfunctions, such as atherosclerosis and diabetes mellitus. Evidence from translational studies or animal/cell work are forthcoming in the delineation of these pathogenetic mechanisms.

Obstructive sleep apnea, inflammation, and the metabolic syndrome

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.

Increase in serum haptoglobin and apolipoprotein M in patients with obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is a common syndrome, which is associated with a number of medical problems that impact morbidity and mortality. Although the precise mechanisms that underlie these associations are not fully understood, previous studies have suggested that patients with OSA show elevations of several biomarkers that are associated with cardiovascular risk. This study was undertaken to identify serum proteins associated with OSA by using a proteomics technique and to examine changes in identified protein levels after continuous positive airway pressure treatment. The study participants consisted of 40 male patients (aged 40-49 years) with severe OSA and 34 male control subjects matched for age and body mass index. All subjects underwent polysomnography. Using a proteomics approach, we identified nine proteins that were differentially expressed in patients with severe OSA and controls. Three of these nine proteins, haptoglobin, paraoxonase-1 and apolipoprotein M, were quantified by using enzyme-linked immunosorbent assays, kinetic assays and by using Western blotting. Multiple regression analysis showed that haptoglobin and apolipoprotein M levels are independently related to apnoea-hypopnoea index (P < 0.01). A further study is required to determine the nature of associations between these identified proteins and OSA in a large population.

Oscillatory pressure wave transmission from the upper airway to the carotid artery

Snoring-associated vibration energy transmission from the upper airway to the carotid artery has been hypothesized as a potential atherosclerotic plaque initiating/rupturing event that may provide a pathogenic mechanism linking snoring and embolic stroke. We examined transmission of oscillatory pressure waves from the pharyngeal lumen to the common carotid artery wall and lumen in seven male, anesthetized, spontaneously breathing New Zealand White rabbits. Airflow was monitored via a pneumotachograph inserted in series in the intact trachea. Fifteen 20-s runs of, separately, 40-, 60-, and 90-Hz oscillatory pressure waves [pressure amplitude in the trachea (Ptr(amp)), amplitude 2-20 cmH(2)O] were generated by a loudspeaker driven by a sine wave generator and amplifier and superimposed on tidal breathing via the cranial tracheal connector. Pressure transducer-tipped catheters measured pressure amplitudes in the tissues adjacent to the common carotid artery bifurcation (Pcti(amp)) and within the lumen (carotid sinus; Pcs(amp)). Data were analyzed using power spectrum analysis and linear mixed-effects statistical modeling. Both the frequency (f) and amplitude of the injected pressure wave influenced Pcti(amp) and Pcs(amp), in that ln Pcti(amp) = 1.2(Ptr(amp)) + 0.02(f) - 5.2, and ln Pcs(amp) = 0.6(Ptr(amp)) + 0.02(f) - 4.9 (both P < 0.05). Across all frequencies tested, transfer of oscillatory pressure across the carotid artery wall was associated with an amplitude gain, as expressed by a Pcs(amp)-to-Pcti(amp) ratio of 1.8 +/- 0.3 (n = 6). Our findings confirm transmission of oscillatory pressure waves from the upper airway lumen to the peripharyngeal tissues and across the carotid artery wall to the lumen. Further studies are required to establish the role of this incident energy in the pathogenesis of carotid artery vascular disease.