Browsing English Journal Articles (Peer Reviewed) by Journal
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Association between lung function decline and obstructive sleep apnoea: the ALEC study.Purpose: To study changes in lung function among individuals with a risk of obstructive sleep apnoea (OSA), and if asthma affected this relationship. Methods: We used data from the European Community Respiratory Health Survey II and III, a multicentre general population study. Participants answered questionnaires and performed spirometry at baseline and 10-year follow-up (n = 4,329 attended both visits). Subjects with high risk for OSA were identified from the multivariable apnoea prediction (MAP) index, calculated from BMI, age, gender, and OSA symptoms at follow-up. Asthma was defined as having doctor's diagnosed asthma at follow-up. Primary outcomes were changes in forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) from baseline to follow-up. Results: Among 5108 participants at follow-up, 991 (19%) had a high risk of OSA based on the MAP index. Participants with high OSA risk more often had wheeze, cough, chest tightness, and breathlessness at follow-up than those with low OSA risk. Lung function declined more rapidly in subjects with high OSA risk (low vs high OSA risk [mean ± SD]: FEV1 = - 41.3 ± 24.3 ml/year vs - 50.8 ± 30.1 ml/year; FVC = - 30.5 ± 31.2 ml/year vs - 45.2 ± 36.3 ml/year). Lung function decline was primarily associated with higher BMI and OSA symptoms. OSA symptoms had a stronger association with lung function decline among asthmatics, compared to non-asthmatics. Conclusion: In the general population, a high probability of obstructive sleep apnoea was related to faster lung function decline in the previous decade. This was driven by a higher BMI and more OSA symptoms among these subjects. The association between OSA symptoms and lung function decline was stronger among asthmatics. Keywords: Asthma; Lung function; Lung function decline; Sleep apnoea.
Changes in sleepiness and 24-h blood pressure following 4 months of CPAP treatment are not mediated by ICAM-1.Objective: Continuous positive airway pressure (CPAP) therapy reduces circulating intercellular adhesion molecule 1 (ICAM-1) in adults with obstructive sleep apnea (OSA). ICAM-1 levels may affect the daytime sleepiness and elevated blood pressure associated with OSA. We evaluated the association of changes from baseline in ICAM-1 with changes of objective and subjective measures of sleepiness, as well as 24-h ambulatory blood pressure monitoring (ABPM) measures, following 4 months of CPAP treatment. Methods: The study sample included adults with newly diagnosed OSA. Plasma ICAM-1, 24-h ABPM, Epworth Sleepiness Scale (ESS), and psychomotor vigilance task (PVT) were obtained at baseline and following adequate CPAP treatment. The associations between changes in natural log ICAM-1 and changes in the number of lapses on PVT, ESS score, and 24-h mean arterial blood pressure (MAP) were assessed using multivariate regression models, controlling for a priori baseline covariates of age, sex, BMI, race, site, smoking status, physical activity, anti-hypertensive medications, AHI, and daily hours of CPAP use. Results: Among 140 adults (83% men), mean (± SD) body mass index (BMI) was 31.5 ± 4.2 kg/m2, and apnea-hyopnea index (AHI) was 36.8 ± 15.3 events/h. Sleepiness measures, although not ICAM-1 or ABPM measures, improved significantly following CPAP treatment. We observed no statistically significant associations between the change in ICAM-1 and changes in sleepiness, MAP, or other ABPM measures. Conclusion: Changes in ICAM-1 levels were not related to changes in sleepiness or ABPM following CPAP treatment of adults with OSA. Future work should explore whether or not other biomarkers may have a role in mediating these treatment outcomes in adults with OSA. Keywords: Ambulatory blood pressure monitoring; Continuous positive airway pressure; Intercellular adhesion molecule-1; Obstructive sleep apnea; Sleepiness.
The design of RIP belts impacts the reliability and quality of the measured respiratory signals.Purpose: Evaluate the effect of respiratory inductance plethysmography (RIP) belt design on the reliability and quality of respiratory signals. A comparison of cannula flow to disposable cut-to-fit, semi-disposable folding and disposable RIP belts was performed in clinical home sleep apnea testing (HSAT) studies. Methods: This was a retrospective study using clinical HSAT studies. The signal reliability of cannula, thorax, and abdomen RIP belts was determined by automatically identifying periods during which the signals did not represent respiratory airflow and breathing movements. Results were verified by manual scoring. RIP flow quality was determined by examining the correlation between the RIP flow and cannula flow when both signals were considered reliable. Results: Of 767 clinical HSAT studies, mean signal reliability of the cut-to-fit, semi-disposable, and disposable thorax RIP belts was 83.0 ± 26.2%, 76.1 ± 24.4%, and 98.5 ± 9.3%, respectively. The signal reliability of the cannula was 92.5 ± 16.1%, 87.0 ± 23.3%, and 85.5 ± 24.5%, respectively. The automatic assessment of signal reliability for the RIP belts and cannula flow had a sensitivity of 50% and a specificity of 99% compared with manual assessment. The mean correlation of cannula flow to RIP flow from the cut-to-fit, semi-disposable, and disposable RIP belts was 0.79 ± 0.24, 0.52 ± 0.20, and 0.86 ± 0.18, respectively. Conclusion: The design of RIP belts affects the reliability and quality of respiratory signals. The disposable RIP belts that had integrated contacts and did not fold on top of themselves performed the best. The cut-to-fit RIP belts were most likely to be unreliable, and the semi-disposable folding belts produced the lowest-quality RIP flow signals compared to the cannula flow signal. Keywords: Obstructive sleep apnea (OSA); Respiratory airflow; Respiratory inductance plethysmography (RIP) belts; Signal quality; Signal reliability.
Nasal symptoms increase the risk of snoring and snoring increases the risk of nasal symptoms. A longitudinal population study.Purpose: Humans have a preference for nasal breathing during sleep. This 10-year prospective study aimed to determine if nasal symptoms can predict snoring and also if snoring can predict development of nasal symptoms. The hypothesis proposed is that nasal symptoms affect the risk of snoring 10 years later, whereas snoring does not increase the risk of developing nasal symptoms. Methods: In the cohort study, Respiratory Health in Northern Europe (RHINE), a random population from Denmark, Estonia, Iceland, Norway, and Sweden, born between 1945 and 1973, was investigated by postal questionnaires in 1999-2001 (RHINE II, baseline) and in 2010-2012 (RHINE III, follow-up). The study population consisted of the participants who had answered questions on nasal symptoms such as nasal obstruction, discharge, and sneezing, and also snoring both at baseline and at follow-up (n = 10,112). Results: Nasal symptoms were frequent, reported by 48% of the entire population at baseline, with snoring reported by 24%. Nasal symptoms at baseline increased the risk of snoring at follow-up (adj. OR 1.38; 95% CI 1.22-1.58) after adjusting for age, sex, BMI change between baseline and follow-up, and smoking status. Snoring at baseline was associated with an increased risk of developing nasal symptoms at follow-up (adj. OR 1.22; 95% CI 1.02-1.47). Conclusion: Nasal symptoms are independent risk factors for development of snoring 10 years later, and surprisingly, snoring is a risk factor for the development of nasal symptoms. Keywords: Epidemiology; Nasal obstruction; Sleep; Snoring.