MANDIBLE ENCLOSURE OF UPPER AIRWAY AND WEIGHT IN OBSTRUCTIVE SLEEP-APNEA

Although anatomic lesions and obesity can produce obstructive sleep ap nea (OSA), most subjects with OSA have no recognizable anatomic lesion . We hypothesized that the occurrence of OSA is related to the size of the region enclosed by the mandible and the degree of obesity. We stu died 30 subjects with a range of OSA and obesity with magnetic resonan ce imaging (MRI). MRI was performed with T-1 weighted sequences. Noctu rnal polysomnography was performed in all subjects. Univariate regress ion analysis indicated there was a significant correlation between the number of apneas and hypopneas per hour of sleep (AH/h) and (1) the a rea enclosed by the mandible ramus (AMR1) (r = 0.48, p < 0.01) and (2) the distance from the teeth to the posterior mandible ramus (r = 0.39 , p < 0.05). Stepwise multiple regression analysis indicated that weig ht, AMR1, and height explained 69% of the variance of AH/h (r2 = 0.69) . We conclude that the occurrence of OSA in these subjects is related to the size of the region enclosed by the mandible as well as to their weight.