Risk Factors for Severe Obstructive Sleep Apnea Including Sleeping Position and its Gender Difference : A Retrospective Single-institute Study in Japan

• Published in: THE SHINSHU MEDICAL JOURNAL Vol. 69; no. 6; pp. 363 - 371
• Main Authors: NOZAWA, Shuhei, URUSHIHATA, Kazuhisa, MACHIDA, Ryosuke, HANAOKA, Masayuki
• Format: Journal Article
• Language: English; Japanese
• Published: The Shinshu Medical Society 10.12.2021
• Subjects: cephalometry; gender difference; obstructive sleep apnea; risk factor; sleeping position
• ISSN: 0037-3826; 1884-6580
• DOI: 10.11441/shinshumedj.69.363

Purpose : Obstructive sleep apnea (OSA) is a disease characterized by sleep-disordered breathing (SDB) due to upper airway obstruction. Age, body mass index (BMI) and abnormal facial morphology which is evaluated by cephalometry have been reported as risk factors for severe OSA. In addition, the supine sleeping position worsens SDB because it narrows the upper airway. We thought that the percentage of supine position during sleep might be a risk factor for worsening apnea-hypopnea index (AHI) levels but it has not been verified. Therefore, we analyzed that and its gender difference. Methods : Between May 2008 and May 2020, 228 patients with OSA who underwent full-night polysomnography (PSG) and cephalometry at our hospital were registered retrospectively. We conducted logistic regression analysis using their clinical background, findings on cephalometry and the percentage of supine position during sleep recorded on full-night PSG to identify risk factors for severe AHI levels (≥30 events/h). Subsequently, subanalyses which classified them by gender were performed. Results : The logistic regression analysis indicated that the percentage of supine position during sleep was a significant risk factor in addition to BMI and the distance from the mandibular plane to the hyoid (MP-H) on cephalometry. A sub-analysis for male patients produced the same results. However, in a sub-analysis for female patients, the risk factors were age and BMI, but not the percentage of supine position during sleep. Conclusions : The percentage of supine position during sleep is one of the risk factors for severe OSA, but only applies to male patients.