Prevalence and Predictors of Atherogenic Serum Lipoprotein Dyslipidemia in Women with Obstructive Sleep Apnea

Genetic variations of low-density lipoprotein cholesterol on metabolic disorders in obstructive sleep apnea

BACKGROUND

The study aimed to explore the relationship between low-density lipoprotein cholesterol (LDL-C) genetic variants and obstructive sleep apnea (OSA) and its complications, including cardiovascular diseases (CVD), insulin resistance (IR), and metabolic syndrome (MS).

METHOD

4329 individuals with suspected OSA who underwent a comprehensive assessment of anthropometric, biochemical, and polysomnography (PSG) data, along with 30 LDL-C single nucleotide polymorphisms (SNPs) were enrolled. The 10-year Framingham CVD risk score (FRS), IR and MS were evaluated for each subject. Linear regression and logistic regression were utilized to examine the correlations among these variables.

RESULTS

After the Benjamini-Hochberg correction, linear regression results indicated positive correlations between variants rs3741297 and rs629301 with FRS (β = 0.031, PBH=0.002; β = 0.026, PBH=0.015). Logistic regression revealed that rs3741297 increased MS risk among total subjects [OR = 1.67 (95% CI:1.369-2.038), PBH=1.32 × 10- 5] and increased IR risk in females [OR = 3.475 (95% CI:1.653-7.307), PBH=0.03]. In males, rs2642438 decreased MS risk [OR = 0.81 (95% CI:0.703-0.933), PBH=0.045].

CONCLUSIONS

The rs3741297 variant correlated with susceptibility to CVD, IR, and MS in the OSA population. OSA, CVD, IR and MS share a potentially common genetic background, which may promote precision medicine.

CINICAL TRIAL REGISTRATION

The study protocol was registered with the Chinese Clinical Trial Registry (ChiCTR1900025714).

Dyslipidemia prevalence in nonobese, nondiabetic patients with obstructive sleep apnea: does sex matter?

STUDY OBJECTIVES

Dyslipidemia in obstructive sleep apnea (OSA) has been attributed to confounding obesity and/or diabetes. This study aimed to examine lipid profiles in nondiabetic, nonobese patients with OSA and identify the possible effects of age and sex.

METHODS

We retrospectively evaluated the lipid parameters of 3,050 adults who underwent polysomnography. A total of 2,168 patients were excluded due to obesity (body mass index ≥ 30 kg/m2), diabetes, alcoholism, untreated hypothyroidism, lipid-lowering drug use, missing sleep data, or treatment for suspected OSA.

RESULTS

Of 882 patients (75% males, aged 46.8 ± 12.2 years) included in the study, 88.4% had OSA. Levels of total cholesterol (P = .003), low-density-lipoprotein (LDL) cholesterol (P = .005), non-high-density-lipoprotein (non-HDL) cholesterol (P = .001), and triglycerides (P = .007) were significantly higher in patients with OSA than in those without, whereas HDL-cholesterol levels did not differ. The proportion of patients with hypercholesterolemia and/or elevated non-HDL cholesterol (>  160 mg/dL) was significantly higher in OSA than in non-OSA. Correlation analyses by sex revealed stronger and more significant relationships between lipid parameters and apnea-hypopnea index in women than in men (r = .135, P < .001, vs r = .080, P = .043 for total cholesterol; r = .111, P < .001, vs r = .080, P = .046 for non-HDL cholesterol; r = .122, P < .001, vs r = .061, P = .107 for LDL cholesterol, respectively). In regression analysis, the rate of hypercholesterolemia increased with age (P < .001 for women and P = .031 for men); non-HDL- and LDL-cholesterol levels significantly increased with OSA severity (P = .035 and P = .023, respectively) and age (P = .004 and P = .001, respectively) in women.

CONCLUSIONS

After excluding confounding obesity and diabetes, patients with OSA have an impaired lipid profile including total cholesterol, LDL cholesterol, non-HDL cholesterol, and triglycerides. A significant association between dyslipidemia and OSA severity was observed in women but not in men.

CITATION

Basoglu OK, Tasbakan MS, Kayikcioglu M. Dyslipidemia prevalence in nonobese, nondiabetic patients with obstructive sleep apnea: does sex matter? J Clin Sleep Med. 2023;19(5):889-898.

The impact of left ventricular geometry on left atrium phasic function in obstructive sleep apnea syndrome: a multimodal echocardiography investigation

BACKGROUND

Left ventricular geometry and left atrium (LA) enlargement are risk factors for cardiovascular disease. However, reports on the relationship between left ventricular geometry and LA volume yielded contradictory findings, and LA phasic function remains unclear. Hence, this study aimed to investigate the influence of left ventricular geometry on LA volume and phasic function in patients with obstructive sleep apnea syndrome (OSAS) via a multimodal echocardiographic approach.

METHODS

In this cross-sectional study, 221 patients with OSAS (age 20-68 years, mean age 45.27 ± 12.50 years) underwent clinical evaluation, polysomnography, and multimodal echocardiographic examination with two-dimensional echocardiography (2DE), two-dimensional speckle-tracking echocardiography (2D-STE) and three-dimensional echocardiography (3DE). Based on conventional classification of left ventricular geometry, patients with OSAS were divided into four groups: normal geometry (NG), concentric remodeling (CR), concentric hypertrophy (CH), and eccentric hypertrophy (EH).

RESULTS

Based on 2DE and 3DE, the LA volumes and indices gradually increased from NG to CH. Additionally, 2DE and 3DE LA maximum volume index (LAVImax) were higher in patients with CH and EH than in patients with NG and CR (P < 0.05). The reservoir function, estimated by LA total emptying fraction (LA TotEF) was lower in patients with CH than in patients with NG in 2DE and 3DE (both, P < 0.05). Also, LA conduit function, evaluated by LA passive emptying fraction (LA PassEF) was lower in patients with CH than in patients with NG and CR, and in patients with EH than in those with NG in 2DE and 3DE (all, P < 0.05). The LA booster pump function, evaluated by LA active emptying fraction (LA ActEF) showed no statistically significant difference in 2DE; however, it was greater in patients with CH than in those with NG in 3DE. Similar results were obtained by 2D-STE, and CH was significantly associated with LA strain during systole (LAS-S, β = - 0.546, 95%CI: - 6.371-(- 3.444); P < 0.001), early diastole (LAS-E, β = - 0.636, 95%CI: - 9.532-(- 5.710); P < 0.001), and late diastole (LAS-A, β = - 0.450, 95%CI: 1.518-3.909; P < 0.001) in multiple linear regression.

CONCLUSIONS

The LA phasic function changed with left ventricular geometry via multimodal echocardiography. CH had the most notable negative effect on the maximum volume and phasic function of the LA.

Snoring Is Associated With Increased Risk of Stroke: A Cumulative Meta-Analysis

Background: Several studies have suggested that snoring is associated with an increased risk of stroke; however, the results are inconsistent. We aim to conduct a systematic review and meta-analysis of observational studies assessing the association between snoring and the risk of stroke in adults.

Methods: We searched PubMed for relevant studies. A random-effect model was adopted to summary relative risks (RRs), and forest plots from a cumulative meta-analysis method were used for a better presentation of how the pooled RRs changed as updated evidence accumulated.

Results: The literature search yielded 16 articles that met our inclusion criteria, and a total of 3,598 stroke patients and 145,901 participants were finally included in our analysis. A consistent trend toward association was found after the initial discovery, and the summary analysis indicated that snoring is associated with a 46% (RR, 1.46; 95%CI, 1.29–1.63; p < 0.001) increased risk of stroke.

Conclusions: Snoring is associated with a significantly increased risk for stroke, up to 46%. The importance of the current study lies in that we provide an imputes to take a more active approach against the increased risk of stroke in snorers.

The effects of continuous positive airway pressure and mandibular advancement therapy on metabolic outcomes of patients with mild obstructive sleep apnea: a randomized controlled study

BACKGROUND

Moderate and severe obstructive sleep apnea (OSA) have been independently associated with dyslipidemia. The results of metabolic improvement with continuous positive airway pressure (CPAP) have been controversial. Less evidence exists regarding this issue in mild OSA. A current treatment for mild OSA is mandibular advancement device (MAD) therapy, but its effectiveness on the metabolic profile needs to be compared with CPAP. The purpose of this study was to compare MAD vs CPAP vs no treatment on the metabolic profile during 6 and 12 months of follow-up in patients with mild OSA.

METHODS

The inclusion criteria were patients with mild OSA, both genders, ages 18 to 65 years, and body mass index (BMI) of < 35 Kg/m². Patients were randomized in 3 groups (CPAP, MAD, and control). The evaluations included physical examination, metabolic profile, and full polysomnography at baseline, 6 months, and 12 months of follow-up.

RESULTS

Seventy-nine patients with mild OSA were randomized in three treatment groups, with mean age (± SD) of 47 ± 9 years, 54% men, and AHI 9.5 ± 2.9 events/h. MAD and CPAP reduced AHI at 6 and 12 months compared to the control group. MAD adherence was higher than CPAP at 6 and 12 months. Despite lower adherence compared to MAD, CPAP was more effective in reducing total cholesterol over 12 months (baseline 189.3 ± 60.2 mg/dl to 173.4 ± 74.3 mg/dl) and low-density lipoprotein cholesterol (LDL-c, baseline 112.8 ± 54.9 mg/dl to 94.5 ± 67.4 mg/dl).

CONCLUSIONS

After 1 year of treatment, CPAP was superior to MAD in reducing total cholesterol and LDL-c in patients with mild OSA.

Sleep Duration, Lipid Profile and Insulin Resistance: Potential Role of Lipoprotein(a)

Lipoprotein (a) (Lp(a)) is considered a genetic factor for cardiovascular disease playing an important role in atherogenesis and thrombosis, but the evidence about its association with sleep duration is controversial. We evaluated the relation between self-reported sleep duration and Lp(a). Among 1600 participants of the population-based sample, we selected 1427 subjects without previously known cardiovascular events, who answered the questions about their sleep duration; had valid lipid profile results (total cholesterol, low- and high-density lipoproteins, Lp(a), apolipoprotein AI (ApoAI), ApoB, and ApoB/ApoAI); and did not take lipid-lowering drugs (mean age 46 ± 12 years). We performed a structured interview, which included questions about lifestyle, medical history, complaints, and sleep duration (How long have you been sleeping per night during the last month?). Sleep duration was classified as follows: <6 h/night—short, 6–9 h/night—normal, and ≥10 h/night—long. Overall, 73 respondents (5.2%) were short-sleepers and 69 (4.8%) long-sleepers. Males were slightly more prevalent among short-sleepers. The groups matched by age, body mass index, blood pressure, diabetes mellitus, and hypertension rate. Short-sleepers had lower rates of high total cholesterol (≥5.0 mmol/L), lower Lp(a) levels and lower rates of increased Lp(a) ≥0.5 g/L, and higher insulin and insulin resistance (assessed by the homeostatic model assessment for insulin resistance (HOMA-IR)). ApoAI, ApoB, their ratio, and other lab tests were similar in the groups. The multinomial logistic regression demonstrated that only the short sleep duration was independently (odds ratio (OR) 0.29, 95% confidence interval (CI) (0.09–0.91), p = 0.033) associated with Lp(a) (χ² = 41.58, p = 0.003). Other influencing factors were smoking and HOMA-IR. Such an association was not found for long-sleepers. In conclusion, a short-sleep duration is associated with Lp(a). The latter might mediate the higher insulin resistance and higher cardiometabolic risks in short-sleepers.

The use of visceral adiposity variables in the prediction of obstructive sleep apnea: evidence from a large cross-sectional study

PURPOSE

The purposes of this study were to evaluate the ability of visceral adiposity variables [the lipid accumulation product (LAP), the visceral adiposity index (VAI), and the triglyceride-glucose index (TyG)] in predicting obstructive sleep apnea hypopnea syndrome (OSAHS) and to determine the effect of sex on the prediction.

METHODS

A total of 5539 subjects admitted to the sleep center for suspected OSAHS were consecutively recruited from 2007 to 2016. Anthropometric measurements, biological indicators, Epworth sleepiness scale score, and polysomnographic variables were collected. Prediction models for diagnosing OSAHS were established in the test group by logistic regression and verified in the validation group by receiver operating characteristic (ROC) curves.

RESULTS

A total of 4703 patients were included in total. LAP and TyG were of moderate diagnostic accuracy for OSAHS, with the diagnostic efficiency differing between men and women. A prediction model was developed that combined visceral adiposity indicators with waist circumstance and the lowest SpO₂. The sensitivity of those indicators were both 84% in men and women, respectively, and their specificity were both 90%. In addition, the model was confirmed in the validation group with a sensitivity and specificity of 83% and 85% in men and 85% and 84% in women.

CONCLUSIONS

LAP and TyG were of moderate efficiency in screening for OSAHS. The prediction model provides a simple and practical screening tool for OSAHS.

The Impact of Bariatric Surgery on Cardiopulmonary Function: Analyzing VO2 Recovery Kinetics

PURPOSE

To assess cardiopulmonary capacity, autonomic heart function, and oxygen recovery kinetics during exercise testing before and after bariatric surgery.

METHODS

This is a prospective cohort study. Symptom-limited cardiopulmonary exercise testing was performed with 24 patients, 1 week before and 4 months after bariatric surgery. The main variables were maximum oxygen uptake (VO₂ max), the time elapsed until the appearance of the first ventilatory threshold (TLV1), and VO₂ oxygen kinetics during recovery with a 50% reduction in peak oxygen uptake in the recovery period after exercise (50%VO₂RP).

RESULTS

The study demonstrated that the peak VO₂\kg increased significantly after bariatric surgery. When analyzed without adjusting for weight, the peak VO₂ paradoxically and significantly decreased after the surgical procedure (p = 0.007). The exercise time until the anaerobic threshold was longer after surgical procedure than before it (p = 0.001). Regarding post-exercise oxygen recovery kinetics, there was a faster reduction in the peak oxygen uptake after bariatric surgery than before the procedure (p < 0.001).

CONCLUSIONS

There was an obvious cardiac autonomic improvement after surgery. Despite the improvement in exercise tolerance, patients undergoing bariatric surgery had lower maximum oxygen consumption in the analysis not corrected for body weight. The mean VO₂RP before bariatric surgery was 141 s and was 111 s after the surgical procedure (p < 0.001). These results suggest an improvement in the recovery kinetics of oxygen consumption, a novel index of cardiac reserve capacity, on patients undergoing bariatric surgery.

Effect modification by gender of the influence of obstructive sleep apnoea characteristics on dyslipidaemia in China: a cross-sectional study

OBJECTIVES

Obstructive sleep apnoea (OSA) characteristics differ by gender, possibly affecting any association between OSA and dyslipidaemia. We explored whether gender influenced any association between OSA characteristics and dyslipidaemia.

METHODS/DESIGN

This was a cross-sectional, large-scale hospital-based study. Male and female risks of dyslipidaemia by OSA characteristics were assessed with logistic regression. Additive interactions were measured using three indices: the relative excess risk due to interaction, the attributable proportion due to interaction and the synergy index. Multiplicative interaction was evaluated via logistic regression.

SETTING

A single secondary-care setting in China.

PARTICIPANTS

3760 patients with OSA.

PRIMARY AND SECONDARY OUTCOME MEASURES

Outcomes were male and female risks of dyslipidaemia, and the associated additive and multiplicative interactions between the apnoea-hypopnea index (AHI), the oxygen-desaturation index (ODI), the microarousal index (MAI), and gender.

RESULTS

After controlling for confounding factors, males (but not females) with AHIs>30 were at higher risk of hyper-total cholesterol (TC), hypo-high-density lipoprotein cholesterol (HDL-C) status and a hyper-TC/HDL-C ratio than males with AHIs≤30. Positive additive interactions were evident between the male gender and AHI on a hyper-TC/HDL-C ratio and hypo-HDL-C status. Males with ODIs>40.1 were at higher risk of hypo-HDL-C status and a hyper-TC/HDL-C ratio than males with ODIs≤40.1. Positive additive and multiplicative interactions were evident between male gender and ODI on hyper-TC/HDL-C ratio. Males with MAIs>28.6 were at higher risk of hyper-TC and hyper-low-density lipoprotein cholesterol status than males with MAIs≤28.6, but no statistically significant interactions were apparent between gender and MAI.

CONCLUSIONS

Males (but not females) with higher AHIs, ODIs or MAIs were at higher risks of some measures of dyslipidaemia. Positive interactions between male and severe OSA or intermittent hypoxia on some measures of dyslipidaemia were apparent. Thus, dyslipidaemia should be evaluated in patients with OSA, especially males with severe OSA or intermittent hypoxia.

Effects of CPAP on the transcriptional signatures in patients with obstructive sleep apnea via coexpression network analysis

A growing number of studies provide epidemiological evidence linking obstructive sleep apnea (OSA) with a number of chronic disorders. Transcriptional analyses have been conducted to analyze the gene expression data. However, the weighted gene coexpression network analysis (WGCNA) method has not been applied to determine the transcriptional consequence of continuous positive airway pressure (CPAP) therapy in patients with severe OSA. The aim of this study was to identify key pathways and genes in patients with OSA that are influenced by CPAP treatment and uncover/unveil potential molecular mechanisms using WGCNA. We analyzed the microarray data of OSA (GSE 49800) listed in the Gene Expression Omnibus database. Coexpression modules were constructed using WGCNA. In addition, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were also conducted. After the initial data processing, 5101 expressed gene profiles were identified. Next, a weighted gene coexpression network was established and 16 modules of coexpressed genes were identified. The interaction analysis demonstrated a relative independence of gene expression in these modules. The black module, tan module, midnightblue module, pink module, and greenyellow module were significantly associated with the alterations in circulating leukocyte gene expression at baseline and after exposure to CPAP. The five hub genes were considered to be candidate OSA‐related genes after CPAP treatment. Functional enrichment analysis revealed that steroid biosynthesis, amino sugar and nucleotide sugar metabolism, protein processing in the endoplasmic reticulum, and the insulin signaling pathway play critical roles in the development of OSA in circulating leukocyte gene expression at baseline and after exposure to CPAP. Using this new systems biology approach, we identified several genes and pathways that appear to be critical to OSA after CPAP treatment, and these findings provide a better understanding of OSA pathogenesis.