Background Obstructive sleep apnoea (OSA) is one of the major sources of the excessive daily sleepiness, cognitive dysfunction, and it increases cardiovascular morbidity and mortality. Previous studies suggested a possible genetic influence, based on questionnaires but no objective genetic study was conducted to understand the exact variance underpinned by genetic factors. Methods Seventy-one Hungarian twin pairs involved from the Hungarian Twin Registry (48 monozygotic, MZ and 23 dizygotic, DZ pairs, mean age 51 ± 15 years) underwent overnight polysomnography (Somnoscreen Plus Tele PSG, Somnomedics GMBH, Germany). Apnoea hypopnea index (AHI), respiratory disturbance index (RDI) and oxygen desaturation index (ODI) were registered. Daytime sleepiness was measured with the Epworth Sleepiness Scale (ESS). Bivariate heritability analysis was applied. Results The prevalence of OSA was 41% in our study population. The heritability of the AHI, ODI and RDI ranged between 69% and 83%, while the OSA, defined by an AHI ≥5/h, was itself 73% heritable. The unshared environmental component explained the rest of the variance between 17% and 31%. Daytime sleepiness was mostly determined by the environment, and the variance was influenced in 34% by the additive genetic factors. These associations were present after additional adjustment for body mass index. Conclusion OSA and the indices of OSA severity are heritable, while daytime sleepiness is mostly influenced by environmental factors. Further studies should elucidate whether close relatives of patients with OSA may benefit from early family risk based screening.

CW variants may not be determined by substantial genetic effects and are not influenced by altered blood flow in healthy individuals. Further investigations are needed to identify potential environmental factors affecting these variants.

Background: Obstructive sleep apnoea (OSA) is a risk factor for cardiovascular disease. Alterations in the gut microbiome have been implicated in the development of cardiovascular disease and may potentially link OSA to its cardiovascular consequences. However, only one study to date has investigated gut microbiomes in adult patients with OSA. Methods: 19 patients with OSA and 20 non-OSA controls participated in the study. Following a diagnostic sleep study, blood was collected for metabolic profiling, and the subjects provided a stool sample for microbiome analysis. The gut microbiome was investigated using the 16S ribosomal RNA method. Results: Patients with OSA had a higher relative abundance of the Proteobacteria phylum (p = 0.03), Gammaproteobacteria class (p = 0.01), Lactobacillae family (p = 0.02), Lactobacillus (p = 0.03), and Roseburia genus (p = 0.03), and a lower abundance of the Actinobacteria phylum (p = 0.03). The abundance of Proteobacteria, Gammaproteobacteria, Lactobacillae, and Lactobacillus were related to disease severity and dyslipidaemia (all p < 0.05), whilst the abundance of Proteobacteria and Gammaproteobacteria was also related to hypertension and cardiovascular disease (all p < 0.05). However, following adjustment for relevant confounders only the association between OSA and Actinobacteria remained significant (p = 0.04). Conclusions: Obstructive sleep apnoea is associated with only subtle changes in gut microbiome. Further studies should investigate gut dysbiosis in OSA.

Previous studies suggested cervical spondylosis as a risk factor for development of obstructive sleep apnoea (OSA). We aimed to assess lumbar disc degeneration in patients with OSA and correlate the findings with symptoms and disease severity. Twenty-seven patients with OSA and 29 non-OSA controls underwent sleep studies and lumbar magnetic resonance imaging (MRI), and completed the Epworth Sleepiness Scale and the 24-item Roland‐Morris Disability Questionnaire questionnaires. Plasma klotho was determined with enzyme-linked immunosorbent assay.Patients with OSA had higher number of disc bulges (4.6±3.7 vs. 1.7±2.5, p<0.01) and anterior spondylophytes (2.7±4.2 vs. 0.8±2.1, p<0.01), increased Pfirrmann score (16.7±4.7 vs. 13.2±4.1, p<0.01) and vertebral fatty degeneration (7.8±4.7 vs. 3.8±3.7, p<0.01). Markers of OSA severity, including the apnoea-hypopnoea index, oxygen desaturation index and percentage of total sleep time spent with saturation <90% as well as plasma levels of klotho were correlated with the number of disc bulges and anterior spondylophytes following adjustment on age, gender and body mass index (all p<0.05). Markers of disc degeneration were related to chronic pain.OSA is associated with lumbar spondylosis likely through chronic intermittent hypoxaemia inducing inflammation in the lumbar discs. Our study highlights the importance of lumbar imaging in patients with OSA reporting lower back pain.

Previous studies suggested cervical spondylosis as a risk factor for development of obstructive sleep apnoea (OSA). We aimed to assess lumbar disc degeneration in patients with OSA and correlate the findings with symptoms and disease severity. Twenty-seven patients with OSA and 29 non-OSA controls underwent sleep studies and lumbar magnetic resonance imaging (MRI), and completed the Epworth Sleepiness Scale and the 24-item Roland‐Morris Disability Questionnaire (RMDQ) questionnaires. Plasma klotho was determined with enzyme-linked immunosorbent assay. Patients with OSA had higher number of disc bulges (4.6 ± 3.7 vs. 1.7 ± 2.5, p < 0.01) and anterior spondylophytes (2.7 ± 4.2 vs. 0.8 ± 2.1, p < 0.01), increased disc degeneration (total Pfirrmann score 16.7 ± 4.7 vs. 13.2 ± 4.1, p < 0.01) and vertebral fatty degeneration (7.8 ± 4.7 vs. 3.8 ± 3.7, p < 0.01). There was no difference in the RMDQ score (0/0–3.5/ vs. 0/0–1/, p > 0.05). Markers of OSA severity, including the oxygen desaturation index and percentage of total sleep time spent with saturation < 90% as well as plasma levels of klotho were correlated with the number of disc bulges and anterior spondylophytes (all p < 0.05). OSA is associated with lumbar spondylosis. Our study highlights the importance of lumbar imaging in patients with OSA reporting lower back pain.

Objectives of the study Nonalcoholic fatty liver disease (NAFLD) is a common condition with a subset of individuals developing liver fibrosis as a major risk factor for advanced liver disease. The contribution of genetic factors to this progression remains incompletely understood. Our aim was to analyze heritability in the development of liver fibrosis estimated by ultrasound shear wave elastography (SWE) in an asymptomatic adult twin cohort. Methods In total 172 adult Hungarian twins (51 monozygotic and 36 dizygotic pairs; 63% women; mean age 54.9 ± 15.1 years) underwent B-mode ultrasonography to assess steatosis and SWE to determine Young’s modulus as a noninvasive marker or liver fibrosis. Results We identified 99 subjects with steatosis, which was mild in 46 subjects (46%), moderate in 52 subjects (52%) and severe in a single subject (1%). Mean Young’s modulus was 7.58 ± 3.53 kPa in this slightly overweight study cohort (BMI: 25.7 ± 4.6 kg/m2). Univariate analysis adjusted for age, sex and BMI indicated no discernible role for genetic components in the presence of liver stiffness, whereas shared and unshared environmental effects accounted for 38.3% (95% confidence interval (CI), 17–56.1%) and 61.7% (95% CI, 43.9–83%). Conclusions Our findings do not support the heritability of liver stiffness in an asymptomatic, twin cohort with slight overweight and variable degree of steatosis, underscoring the importance of environmental factors in the development of NAFLD and liver fibrosis.

Introduction: Obstructive sleep apnea (OSA) is a common disorder characterized by the repetitive collapse of the upper airways during sleep, most likely in the oropharyngeal region. Anatomical factors significantly contribute to the disease development; however, the heritability of the upper airway dimensions, which lead to the collapsibility of the upper airways, is less known. In the current study, we aimed to quantify the impact of heritable and environmental factors on the upper airway dimensions in twins using magnetic resonance imaging (MRI). Methods: We completed head and neck MRI imaging on 110 (66 monozygotic and 44 dizygotic, age median and Q1–Q3: 53 (44–63.75) years) adult twins from the Hungarian Twin Registry. We completed cephalometric, soft tissue and fatty tissue space measurements on T1- and T2-weighted images in sagittal, coronal and axial planes. For the analysis of the genetic and environmental, the determination of the measured parameters was performed with an ACE twin statistical model. Results: We found a strong genetic determination in the anteroposterior diameter of the tongue and the thickness of the submental fatty tissue of the neck. Other parameters of the tongue, soft palate and uvula have shown moderate heritability, while we found strong environmental determination in the thickness of the parapharyngeal fatty tissue, the thickness of the pharyngeal wall, and the smallest diameter of the posterior upper airways. Conclusion: Our twin study can help better understand the genetic and environmental background of anatomical structures involved in the development of sleep apnea.

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