Craniofacial differences according to the body mass index of patients with obstructive sleep apnoea syndrome: cephalometric study in 85 patients.

We examined the craniofacial characteristics of patients with obstructive sleep apnoea syndrome (OSAS) and correlated them with the body mass index (BMI (weight (kg) x height (m2)). Eighty-five men with OSAS diagnosed by conventional polysomonography were divided into two groups according to their BMI (< 30 and > or = 30). Cephalometry was analysed by using 31 measurements of the size of the bone structures, their relationships and the size of the airways. The groups were comparable for age and the apnoea-hypopnoea index (mean 49, standard deviation (SD) 23). Patient with a BMI < 30 had a shorter anterior floor of cranial base, a smaller mandible and retroposition of the mandible compared with severly obese patients. These skeletal differences were associated with narrower velopharyngeal and linguopharyngeal spaces. This study sh ows that there is a craniofacial difference between two populations, divided according to their BMI.