Gender and the systemic hypertension-snoring association: a questionnaire-based case-control study

The Impact of Intermittent Hypoxia on Metabolism and Cognition

Intermittent hypoxia (IH), one of the primary pathologies of sleep apnea syndrome (SAS), exposes cells throughout the body to repeated cycles of hypoxia/normoxia that result in oxidative stress and systemic inflammation. Since SAS is epidemiologically strongly correlated with type 2 diabetes/insulin resistance, obesity, hypertension, and dyslipidemia included in metabolic syndrome, the effects of IH on gene expression in the corresponding cells of each organ have been studied intensively to clarify the molecular mechanism of the association between SAS and metabolic syndrome. Dementia has recently been recognized as a serious health problem due to its increasing incidence, and a large body of evidence has shown its strong correlation with SAS and metabolic disorders. In this narrative review, we first outline the effects of IH on the expression of genes related to metabolism in neuronal cells, pancreatic β cells, hepatocytes, adipocytes, myocytes, and renal cells (mainly based on the results of our experiments). Next, we discuss the literature regarding the mechanisms by which metabolic disorders and IH develop dementia to understand how IH directly and indirectly leads to the development of dementia.

Intermittent Hypoxia Increased the Expression of DBH and PNMT in Neuroblastoma Cells via MicroRNA-375-Mediated Mechanism

Sleep apnea syndrome (SAS), characterized by recurrent episodes of oxygen desaturation and reoxygenation (intermittent hypoxia (IH)), is a risk factor for hypertension and insulin resistance. We report a correlation between IH and insulin resistance/diabetes. However, the reason why hypertension is induced by IH is elusive. Here, we investigated the effect of IH on the expression of catecholamine-metabolizing enzymes using an in vitro IH system. Human and mouse neuroblastoma cells (NB-1 and Neuro-2a) were exposed to IH or normoxia for 24 h. Real-time RT-PCR revealed that IH significantly increased the mRNA levels of dopamine β-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) in both NB-1 and Neuro-2a. Western blot showed that the expression of DBH and PNMT in the NB-1 cells was significantly increased by IH. Reporter assays revealed that promoter activities of DBH and PNMT were not increased by IH. The miR-375 level of IH-treated cells was significantly decreased relative to that of normoxia-treated cells. The IH-induced up-regulation of DBH and PNMT was abolished by the introduction of the miR-375 mimic, but not by the control RNA. These results indicate that IH stress increases levels of DBH and PNMT via the inhibition of miR-375-mediated mRNA degradation, potentially playing a role in the emergence of hypertension in SAS patients.

Association between self-reported snoring and hypertension: a systematic review and meta-analysis

OBJECTIVES

The purpose of this study is to summarize the evidence for the association between snoring and hypertension and the effect of snoring on hypertension in men and/or women.

METHODS

We searched the articles in the Cochrane Library, PubMed, Scopus, Web of Science and Embase published up to 12 November 2020 to evaluate the association between snoring and hypertension. Studies were selected according to the predefined screening criteria and their qualities were assessed by Newcastle-Ottawa Quality Evaluation Scale. The odds ratio and 95% confidence interval were used as effective indicators. It was registered in PROSPERO with the number: CRD42021224912.

RESULTS

According to the inclusion/exclusion criteria, 11 studies including eight prospective cohort studies and three cross-sectional studies were included. The results showed that compared with non-snoring participants, snoring significantly increased the risk of hypertension in both men and women [odds ratio (OR) = 1.32, 95% confidence interval (CI), 1.23-1.42; men: odds ratio (OR) = 1.32; 95% confidence interval (CI), 1.18-1.49; women: odds ratio (OR) = 1.26; 95% confidence interval (CI), 1.14-1.40]. Besides, the risk of hypertension was significantly increased when the snoring frequency was ≥4 nights/week [frequency≥4 nights/week: odds ratio (OR) = 1.42; 95% confidence interval (CI), 1.21-1.66; 4 nights/week >frequency>0: odds ratio (OR) = 1.23; 95% confidence interval (CI),1.13-1.34].

CONCLUSIONS

Snoring is considered as an independent predictor of hypertension in both men and women, which may play a role in the prevention and control of hypertension. People who snore frequently should pay close attention to their blood pressure levels to prevent hypertension.

Association between self-reported snoring and hypertension among Chinese Han population aged 30-79 in Chongqing, China

Background

We aim to explore the association between self-reported snoring and hypertension among adults aged 30–79 in Chongqing, China.

Methods

A total of 23,342 individuals aged 30–79 were included at baseline from August 2018 to January 2019, and the final sample size for the analysis was 22,423. Face-to-face interviews and physical examinations were conducted by trained investigators. Logistic regression was performed to study age-specific and gender-specific associations between snoring and hypertension.

Results

Frequent snoring was associated with the risk of hypertension for each age and gender group, and the frequency of snoring was positively correlated with the risk for hypertension. For the three age groups (< 45, 45–59, ≥ 60), compared with the non-snoring group, those who snore often had a 64.5%, 53.3%, and 24.5% increased risk of hypertension (< 45: OR = 1.65, 95%CI 1.34–2.02; 45–59: OR = 1.53, 95%CI 1.37–1.72; ≥ 60: OR = 1.25, 95%CI 1.09–1.42), respectively. For men and women, those who snore often had a 46.8% and 97.2% increased risk of hypertension, respectively, than the non-snoring group (men: OR = 1.47, 95%CI 1.33–1.63; women: OR = 1.97, 95%CI 1.75–2.23).

Conclusions

People who snore frequently should pay close attention to their blood pressure levels in order to achieve early prevention of hypertension, particularly for snorers who are female and aged under 45; importance should be attached to their blood pressure control.

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.

Relationship between Snoring and Lifestyle-related Diseases among a Japanese Occupational Population

Objective Snoring is a common physical condition in active workers. However, the link between snoring and health problems is poorly understood. Therefore, the prevalence of snoring in Japanese workers and the relationships between snoring and lifestyle-related diseases were investigated. Methods This was a retrospective, single-center, cross-sectional study. The results of a single year's medical examinations were investigated for 25,141 Japanese active office workers 20 to 59 years old. The presence and duration of snoring were investigated using a personal computer at a medical interview before the medical checkup. The snoring frequency was investigated for each gender. In addition, the relationships between snoring and hypertension, diabetes, and dyslipidemia were also analyzed. Results Men (21,774) were a mean 46±6 years old with a snoring prevalence of 43%. Women (3,367) were a mean 46±6 years old with a snoring prevalence of 20%. In men, snoring was an independent comorbid factor of hypertension and dyslipidemia. In particular, a long snoring vintage (multiple years) was an independent comorbid factor for hypertension [odds ratio (OR), 1.14; 95% confidence interval (CI), 1.05-1.24; p=0.002; and OR, 1.20; 95% CI, 1.07-1.34; p=0.001]. In women, snoring was not an independent comorbid factor for lifestyle-related diseases when adjusted for the age and body mass index. Conclusion Snoring was shown to be a frequent pathophysiology in active workers. It was a health indicator for active workers, and especially in men, intervention for snoring may reduce the risk of developing lifestyle-related diseases.

Nocturnal pulse rate and symptomatic response in patients with obstructive sleep apnoea treated with continuous positive airway pressure for one year

BACKGROUND

Obstructive sleep apnoea (OSA) is the most common form of sleep-disordered breathing and a known risk factor for cardiovascular disease. We hypothesised that in patients with OSA the characteristics of nocturnal pulse rate (PR) are associated with changes in blood pressure and daytime sleepiness, following commencement of continuous positive airway pressure (CPAP) therapy.

METHODS

Pulse oximetry data, demographics, daytime sleepiness and blood pressure were recorded at baseline and at one year follow up. Patients with OSA were grouped according to positive and negative changes in the PR (ΔPR) response during the first night of pulse oximetry before commencement of CPAP.

RESULTS

A total of 115 patients (58 with OSA and 57 matched subjects without OSA) were identified and included in the analysis. The scale of improvement in daytime sleepiness could be predicted by a negative or positive ΔPR, as recorded in the initial screening pulse oximetry [ΔESS -5.8 (5.1) vs. -0.8 (7.2) points, P<0.05]. A negative correlation was observed between mean nocturnal PR and changes in systolic blood pressure (SBP) after one year of CPAP treatment (r=-0.42, P<0.05).

CONCLUSIONS

Mean nocturnal PR prior to CPAP initiation was associated with changes in SBP at one year follow up. A descending nocturnal PR in patients with OSA, prior to CPAP initiation, might help to identify a symptomatic response from long term CPAP treatment.

Cardiovascular disease and health-care utilization in snorers: a population survey

STUDY OBJECTIVES

We assessed the prevalence of self-reported snoring in the Hungarian population and established whether different types of snoring are associated with cardiovascular disorders and increased health-care utilization.

DESIGN

Cross-sectional study. Door-to-door survey.

SETTING

Nationally representative population in Hungary.

PARTICIPANTS

Interviews were carried out in the homes of 12,643 persons. We used the Hungarian National Population Register as the sampling frame and implemented a clustered, stratified sampling procedure. The study population represented 0.16% of the population over the age of 18 years according to age, sex, and 150 subregions of the country.

INTERVENTIONS

Not applicable.

MEASUREMENTS AND RESULTS

Thirty-seven percent of men and 21% of women reported loud snoring with breathing pauses. Hypertension, myocardial infarction, and stroke were reported by 26%, 3%, and 4% of the respondents, respectively. There was a significant increase in the prevalence of hypertension, myocardial infarction, and stroke in quiet and loud snorers, as compared with nonsnorers. Multivariate analysis showed an association between loud snoring and hypertension (odds ratio [OR]: 1.40, 95% confidence interval [CI]: 1.24-1.58), myocardial infarction (OR: 1.34, CI: 1.04-1.73), and stroke (OR: 1.67, CI: 1.32-2.11) after statistical adjustment for age, sex, body mass index, diabetes, level of education, smoking, and alcohol consumption. Loud snoring was also associated with measures of health-care use in both sexes.

CONCLUSIONS

Snoring is frequent in the Hungarian adult population, and loud snoring with breathing pauses, in contrast with quiet snoring, is associated with an increased risk of cardiovascular disease and increased health-care utilization.

Effects of losartan and atenolol on left ventricular mass and neurohormonal profile in patients with essential hypertension and left ventricular hypertrophy

OBJECTIVE

To compare the effects of the angiotensin II antagonist, losartan, with those of atenolol on left ventricular hypertrophy (LVH), blood pressure and neurohormone concentrations in hypertensive patients with LVH.

DESIGN

A multinational, randomized, double-blind trial.

SETTING

Hospital.

PATIENTS

Hypertensive patients with an echocardiographically documented left ventricular mass index (LVMI) 120 g/m(2) (men) or 105 g/m(2) (women).

INTERVENTIONS

Patients allocated randomly to groups received either losartan or atenolol 50 mg/day for 36 weeks, with possible titration to 100 mg/day, and addition of hydrochlorothiazide 12.5 or 25 mg/day.

MAIN OUTCOME MEASURES

Changes in LVMI and sitting systolic (SBP) and diastolic (DBP) blood pressures after 36 weeks of treatment (study powered for non-inferiority hypothesis). All echocardiographic data were read in a central laboratory by staff blinded to the treatments and sequence of echocardiographic tapes.

RESULTS

The estimated treatment difference between the losartan and atenolol regimens (mean change from baseline at week 36) in LVMI was -2.5 g/m(2) [95% confidence interval (CI) -7.36 to 2.37 g/m(2) ] in favor of losartan, indicating that losartan was significantly non-inferior ( 0.001, non-inferiority limit 8 g/m(2) ) and numerically superior to atenolol in reducing LVMI. The losartan-based regimen significantly reduced LVMI after 36 weeks compared with baseline (-6.56 g/m(2) , 95% CI -10.24 to -2.88 g/m(2) , P<0.001), whereas the atenolol-based regimen had no significant effect (-3.71 g/m, 95% CI -7.75 to 0.32 g/m(2) , P= NS). In a subset of 82 patients, significant changes in serum concentrations of atrial natriuretic peptide, brain natriuretic peptide and immunoreactive amino-terminal pro-brain natriuretic peptide were recorded in losartan-treated ( 0.01) but not atenolol-treated patients. Losartan and atenolol significantly decreased SBP and DBP from baseline after 6, 12, 24 and 36 weeks. The changes from baseline in DBP were greater in the atenolol group at weeks 6 and 36 [difference -2.6 mmHg ( P= 0.016) at week 36]. However, both treatment regimens achieved similar SBP/DBP values at week 36 (141.1 +/- 12.8/86.8 +/- 8.2 mmHg for losartan and 141.4 +/- 17.2/85.0 +/- 10.1 mmHg for atenolol, respectively). Overall, losartan treatment was associated with significantly fewer drug-related clinical adverse events, compared with atenolol (10 and 22%, respectively, P= 0.028).

CONCLUSIONS

Both losartan- and atenolol-based regimens effectively decreased blood pressure. Losartan was non-inferior and numerically superior to atenolol in regression of LVH. The reduction in hypertrophy with losartan treatment was accompanied by reductions in circulating concentrations of cardiac natriuretic peptides. Losartan, by specifically blocking angiotensin II, may therefore have effects on the heart beyond those expected from the decrease in blood pressure alone. Losartan was better tolerated than atenolol.

Sleep disordered breathing--a new component of syndrome x?

Sleep disordered breathing (SDB) is a complication of obesity estimated to occur in about 4-6% of overweight individuals. These respiratory disturbances during sleep incorporate a number of conditions including snoring, upper airway resistance syndrome and obstructive sleep apnoea syndrome (OSAS). It is thought that as well as having deleterious effects on sleep quality these conditions may also promote cardiovascular and hormonal changes leading to an elevated blood pressure and an increased incidence of cardiovascular morbidity. Evidence reviewed here points to an alteration in sympathovagal balance, baroreceptor sensitivity, insulin resistance and leptin, growth hormone and lipid levels. Whether these changes are a consequence of the associated obesity or the SDB itself remains to be proven.

Obstructive sleep apnea and hypertension: from correlative to causative relationship

Sleep-disordered breathing, manifested by repetitive episodes of partial or complete cessation of breathing during sleep associated with brief arousal and autonomic activation, is estimated to affect as many as 4% of adult men and 2% of adult women. Studies conducted during the 1980s revealed a strong association between sleep-disordered breathing and hypertension. The results of these early studies, which relied on relatively small samples of patients, have been confirmed in recent years by large-scale epidemiologic studies that are controlled for all possible confounding factors. This paper reviews the evidence suggesting a causative relationship between hypertension and disordered breathing in sleep. The authors discuss the possible underlying mechanisms of the two entities and address the clinical implications of this relationship. They conclude by recommending a proactive approach to the diagnosis of breathing disorders in sleep, in order to prevent the cardiovascular sequelae of this syndrome.

Use of ambulatory blood pressure monitoring to compare antihypertensive efficacy and safety of two angiotensin II receptor antagonists, losartan and valsartan. Losartan Trial Investigators

The efficacy and safety of losartan and valsartan were evaluated in a multicenter, double-blind, randomized trial in patients with mild to moderate essential hypertension. Blood pressure responses to once-daily treatment with either losartan 50 mg (n = 93) or valsartan 80 mg (n = 94) for 6 weeks were assessed through measurements taken in the clinic and by 24-hour ambulatory blood pressure monitoring (ABPM). Both drugs significantly reduced clinic sitting systolic (SiSBP) and diastolic blood pressure (SiDBP) at 2, 4, and 6 weeks. Maximum reductions from baseline in SiSBP and SiDBP on 24-hour ABPM were also significant with the two treatments. The reduction in blood pressure was more consistent across patients in the losartan group, as indicated by a numerically smaller variability in change from baseline on all ABPM measures, which achieved significance at peak (P = .017) and during the day (P = .002). In addition, the numerically larger smoothness index with losartan suggested a more homogeneous antihypertensive effect throughout the 24-hour dosing interval. The antihypertensive response rate was 54% with losartan and 46% with valsartan. Three days after discontinuation of therapy, SiDBP remained below baseline in 73% of losartan and 63% of valsartan patients. Both agents were generally well tolerated. Losartan, but not valsartan, significantly decreased serum uric acid an average 0.4 mg/dL at week 6. In conclusion, once-daily losartan 50 mg and valsartan 80 mg had similar antihypertensive effects in patients with mild to moderate essential hypertension. Losartan produced a more consistent blood pressure-lowering response and significantly lowered uric acid, suggesting potentially meaningful differences between these two A II receptor antagonists.