Craniofacial Phenotyping in Obstructive Sleep Apnea - A Novel Quantitative Photographic Approach

Study Objectives: To compare the craniofacial morphological phenotype of subjects with and without obstructive sleep apnea (OSA) using a quantitative photographic analysis technique. Design: Case-control study; subgroup matched for body mass index (BMI) and sex. Setting: Sleep investigation unit in a university teaching hospital. Patients: 114 subjects (93% Caucasian) with OSA (apnea-hypopnea index [AHI] >= 10/h) and 66 controls (AHI < 10/h). Interventions: Standardized frontal-profile craniofacial photographic imaging performed prior to polysomnography. Photographs were analyzed for the computation of linear, angular, area and polyhedral volume measurements representing dimensions and relationships of the various craniofacial regions. Measurements and Results: Photographic craniofacial phenotypic differences were demonstrated between OSA and control subjects, including a range of measurements of the face, mandible, maxilla, eyes, nose, head and neck. After 1-for-1 subgroup matching for BMI and sex (51 subjects in each group), mandibular length 1 (6.21 +/- 0.08 [mean +/- SEM] vs 6.58 0.08 cm, P = 0.006), mandibular-nasion angle 1 (35.0 +/- 0.48 vs 36.7 +/- 0.37 degrees, P = 0.006) and anterior neck space area (10.2 +/- 0.53 vs 12.2 +/- 0.52 cm(2), P = 0.01) remained smaller in the OSA group. Mandibular width-length angle (88.0 +/- 0.75 vs 85.3 +/- 0.54 degrees, P = 0.005) and face width-midface depth angle (72.3 +/- 0.44 vs 70.7 +/- 0.39 degrees, P = 0.01) remained larger in the OSA group, whereas mandibular triangular area (39.2 +/- 0.63 vs 41.7 +/- 0.74 cm(2), P = 0.01) was smaller. Conclusions: Craniofacial phenotypic differences in OSA in Caucasian subjects can be demonstrated using a photographic analysis technique.