A cephalometric comparison of patients with the sleep apnea/hypopnea syndrome and their siblings.

STUDY OBJECTIVES To define differences in the skeletal components of facial structure predisposing to the obstructive sleep apnea/hypopnea syndrome (OSAHS) by a comparison of the craniofacial complex between people with OSAHS and their siblings without OSAHS. DESIGN Case-control study using sibling pairs. SETTING Scottish Sleep Centre. PARTICIPANTS 104 patients with OSAHS living in Scotland and 107 of their siblings. INTERVENTIONS All subjects had sleep studies, clinical review, and cephalometry performed. All measurements were scored blind to index or control status. MEASUREMENTS AND RESULTS 207 cephalograms were available for analysis, of which 145 were for dentate subjects (90 with definite OSAHS; 55 without). In the dentate subjects, regression analysis (correcting for body mass index and age) showed OSAHS was associated with a significantly longer distance from the hyoid bone to the mandibular plane in men (P = .02) and in women (P = .036). Regression analysis in 22 pairs of dentate brothers, discordant for the diagnosis of OSAHS (controlling for age and body mass index), showed a shorter mandibular corpus (P = .013) and lower hyoid in relation to the mandibular plane (P = .006) to be significantly associated with a diagnosis of OSAHS. CONCLUSIONS Men and women with OSAHS have a lower-set hyoid bone than do those without OSAHS. This occurs independently of obesity and remains even when intersubject variance is minimized by performing pairwise comparison of the craniofacial complex between siblings with and without OSAHS.