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Objectives: The purpose of this study is to evaluate the efficacy of oral appliance (OA) treatment for subjects with severe obstructive sleep apnea (OSA) and to determine the dental parameters associated with treatment outcomes. Study design: This study uses a prospective longitudinal design. Methods: Consecutive Chinese subjects with severe OSA who refused continuous positive airway pressure treatment were recruited. Their dental measurements were taken from lateral cephalometric radiographs. Polysomnograms with OA were repeated at 3 months and 1 year. Blood pressure was taken in the morning after sleep studies. Results: Thirty-four subjects were evaluated at 3 months and 1 year according to the principle of intention-to-treat analysis. OA reduced AHI significantly in subjects with favorable responses, from 49.3 (37.4-67) to 12.5 (6.1-15.7), p < 0.001 at 3 months and from 47.5 (41.1-72.9) to 13.1 (6.0-14.0), p < 0.001 at 1 year. These OSA subjects had an increased overjet at baseline compared to those with unfavorable responses ( p ≤ 0.05). Systolic blood pressure was significantly reduced in those hypertensive OSA subjects after 3 months and 1 year of treatment. Conclusions: OA reduces the severity of sleep apnea, and the effect is maintained at 1 year in subjects with retrognathism. OA appears to reduce systolic blood pressure in hypertensive OSA subjects at 3 months and 1 year. [ABSTRACT FROM AUTHOR]

Background and objective: This study was conducted to define normal reference values and lower limits of normal (LLN) for single-breath carbon monoxide diffusing capacity (DLco) and DLco per unit of alveolar volume (Kco) for Chinese adults in Hong Kong. Methods: Healthy non-smoking men and women aged 18–80 years were recruited by random digit dialling. DLco and Kco were measured according to American Thoracic Society standards. Reference equations were obtained by multiple linear regression; LLN were derived by distribution-free method for estimation of age-related centiles. Results: Tests from 568 subjects (259 men, 309 women) were analysed. DLco declined with age in both genders, and increased with height and the interaction term of height and age in men and women, respectively. Considering Hb values did not improve the reference equations. Kco declined with age and increased with weight in both genders, while height and its interaction term with age were additional determinants in women. The reference DLco was lower than some Caucasian values, and was only explained partially by a smaller body size and alveolar volume in Chinese. The distribution-free method yielded better overall approximation to the fifth percentile compared with the traditional method of determining LLN. Conclusions: The equations for reference values and LLN of diffusing capacity derived in this study are of clinical relevance to Chinese subjects. [ABSTRACT FROM AUTHOR]

Objectives: The self-efficacy measure for sleep apnea (SEMSA) questionnaire was shown to be an effective tool to assess adherence-related cognitions on continuous positive airway pressure (CPAP) therapy in obstructive sleep apnea (OSA) subjects. SEMSA helps to solicit fundamental information for formulating strategies to promote CPAP adherence for better treatment outcomes. The objective of our study was to perform a linguistic and psychometric evaluation of a Chinese version of the SEMSA (SEMSA-C)., Methods: Data were obtained from 100 subjects in a randomized controlled trial (RCT) on CPAP education. Subjects were newly diagnosed of OSA and naïve to CPAP therapy., Results: A 26-item SEMSA-C was obtained by a rigorous linguistic validation process. Internal consistency was high with Cronbach α>0.88. One-week test-retest intraclass correlation coefficient (ICC) ranged from 0.70 to 0.82. Principal component factor analysis identified three of the same hypothesized factors (perceived risks, outcome expectancies, and treatment self-efficacy) as in the original version. CPAP adherence was associated with outcome expectancies and treatment self-efficacy at 3-month assessment. Further, SEMSA-C demonstrated an improvement in self-efficacy after CPAP use., Conclusions: SEMSA-C shows similar psychometric properties as the original English version. It is a reliable and responsive instrument to measure perceived risks, outcome expectancies, and treatment self-efficacy in Chinese subjects with OSA., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: Patients with diabetes mellitus are known to have increased serum levels of advanced glycation end-products (AGEs), and this is also associated with insulin resistance. This study aimed to investigate the relationship between serum AGEs and insulin sensitivity in non-diabetic subjects with obstructive sleep apnoea (OSA)., Methods: Adult males with no known comorbidities were recruited from the sleep clinic of a university teaching hospital. They underwent overnight in-laboratory polysomnography. Fasting blood was taken to measure serum AGE and plasma glucose levels. Insulin sensitivity was estimated using the short insulin tolerance test., Results: In total, 105 subjects with a mean age of 43.5 (standard deviation [SD] 9.2)years, mean body mass index of 27.1 (SD 4.0)kg/m(2), and median apnoea-hypopnoea index (AHI) of 17 (interquartile range 5-46) were analysed. Serum AGE levels were significantly higher in subjects with OSA (AHI ≥5), compared with those without OSA (AHI <5) (3.9 [SD 1.2] vs. 3.2 [SD 0.8]μg/ml, respectively; P=0.037) after adjusting for confounders. AGE levels were positively correlated with AHI (r=0.318, P=0.001), but not with insulin sensitivity. AGE levels decreased in subjects with moderate-to-severe OSA who received continuous positive airway pressure (CPAP) treatment for three months (n=18, P=0.017)., Conclusions: Serum AGE levels correlate with AHI in non-diabetic adult males. This relationship cannot be explained by insulin sensitivity. Supporting the hypothesis of a direct relationship between AHI and AGEs, AGE levels were found to decline with CPAP therapy., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Background: The prognosis of early stage lung cancer was superior to that of late stages. We hypothesize that by using sputum cytology as the first screening method followed by autofluorescence bronchoscopy could detect early stage lung cancer in the central airway., Methods: During 18-month recruitment period, subjects at high risk for lung cancer (ever smoker accumulated more than 20 pack-year and above 40 years) followed up at Chest Clinics were invited to submit sputum for cytological examination. Subjects with sputum atypia were invited to have bronchoscopy, and CT thorax. After a mean follow-up of 39+/-14 months, the characteristics of lung cancers detected in the group with sputum atypia and the group with normal sputum at baseline were assessed., Results: 181 subjects submitted sputum and primary lung cancer were diagnosed in 13. 46.2% of the lung cancers were in early stages. Bronchoscopy were performed in 85, and seven were confirmed to have lung cancer (six were in early stages). 81 had CT done and 92.6% had radiological abnormalities, though three lung cancers (all stage 0) were missed by CT. Five more primary lung cancers were diagnosed during the follow-up period: one in sputum atypia group and the other four (three were advanced adenocarcinoma) in normal sputum group. The overall sensitivity of sputum cytology in detecting lung cancer was 71.4% for all histology and 100% for squamous cell lung cancer., Conclusions: Sputum cytology examination followed by bronchoscopy was a practical way of detecting early stage lung cancer in central airway.