CEPHALOMETRIC AND DEMOGRAPHIC CHARACTERISTICS OF OBSTRUCTIVE SLEEP-APNEA - AN EVALUATION WITH PARTIAL LEAST-SQUARES ANALYSIS

Obstructive sleep apnea (OSA) is caused by repeated obstruction of the upper airway during sleep. The purpose of this study was to test the relative contributions of specific demographic and cephalometric measu rements to OSA severity. Demographic, cephalometric, and overnight pol ysomnographic records of 291 male OSA patients and 49 male nonapneic s norers were evaluated. A partial least squares (PLS) analysis was used for statistical evaluation. The results revealed that the predictive powers of obesity and neck size variables for OSA severity were higher than the cephalometric variables used in this study. Compared with ot her cephalometric characteristics, an extended and forward natural hea d posture, lower hyoid bone position, increased soft palate and tongue dimensions, and decreased nasopharyngeal and velopharyngeal airway di mensions had relatively higher associations with OSA severity. The res piratory disturbance index (RDI) was the OSA outcome variable that was best explained by the demographic and cephalometric predictor variabl es. We conclude that the PLS analysis can successfully summarize the c orrelations between a large number of variables, and that obesity, nec k size, and certain cephalometric measurements may be used together to evaluate OSA severity.