Risk factors for sleep-disordered breathing: the role of craniofacial structure

To evaluate possible differences in craniofacial structure between overweight patients and normal-weight patients with mild sleep-disordered breathing (SDB).

Subjects were recruited from patients referred to Kuopio University Hospital due to suspicion of SDB. They were divided into two groups based on their body mass index (BMI). The overweight group (BMI > 27 kg/m(2)) consisted of 58 males and 19 females and the normal weight group (BMI ≤ 27 kg/m(2)) of 33 males and 15 females. The mean age of the subjects was 51.4 years. All subjects underwent an overnight cardiorespiratory recording. The mean apnea-hypopnea index (AHI) was 9.3 events/h for the entire study population. Occlusion and craniofacial morphology were examined by an experienced orthodontist.

Significant differences in craniofacial morphology and occlusion were found between the groups: the craniofacial profile in normal-weight patients was more convex (P < 0.000) and the mandible more retrusive (P = 0.004) than in overweight subjects. In addition, distal molar occlusion (P = 0.005) was more prevalent in normal-weight subjects, and their overjet and overbite were increased as compared to overweight patients (P = 0.009 and 0.006, respectively). Similarly, cross bite was detected significantly more often in normal-weight subjects (P = 0.052).

These results reveal that deviations in craniofacial morphology and occlusion are more frequent in normal subjects than in overweight subjects with mild SDB; this may well have implications in the pathophysiology of SDB.