Obstructive sleep apnoea: multiple comparisons of cephalometric variables of obese and non-obese patients

Pathogenesis of obstructive sleep apnoea (OSA) is complex and not yet fully understood. Several factors contribute to OSA severity. Obesity is believed to play an important role. Nevertheless, not all OSA patients are obese. Therefore, the different features that cause nocturnal upper airway obstruction in obese and non-obese OSA patients could be expected.

To investigate the different components of cervico-craniofacial skeletal and upper airway soft tissue morphology among obese OSA, non-obese OSA patients and the controls.

One hundred male OSA patients were classified into two groups on the basis of body mass index (BMI) as obese (BMI > or = 30 kg/m2) and non-obese (BMI < 30 kg/m2). Consequently, 57 obese and 43 non-obese OSA patients were examined and compared with a control group of 36 healthy males.

A comprehensive cephalometric analysis of cervico-craniofacial skeletal and upper airway soft tissue morphology was performed. Sixty-eight cephalometric variables were compared among the three groups by one way analysis of variance with Bonferroni's test.

Both OSA groups had aberrations of cervico-craniofacial skeletal as well as upper airway soft tissue morphology when compared with the controls. These anatomic deviations were confined to cervico-craniofacial skeletal structures in the non-obese OSA patients, whereas the obese OSA patients had more abnormalities in the upper airway soft tissue morphology, head posture and position of the hyoid bone.

The findings imply that there should be different treatment regimens for the two subgroups of OSA patients. Cephalometric analysis together with various considerations of BMI is highly recommended as one of the most important tools in diagnosis and treatment planning for OSA patients.