The specific aims were: 1) to quantify upper airway craniofacial structure, soft tissues and regional fat deposition using three dimensional magnetic resonance imaging in order to determine the intermediate traits associated with obstructive sleep apnea utilizing a case control design in normals and apneics; and 2) to determine the upper airway structural risk factors for sleep apnea that demonstrated family aggregation and were most likely to have a genetic component by comparing probands, siblings of probands, neighborhood controls and siblings of neighborhood controls. The resources included an extensive clinical sleep practice, sophisticated NM imaging techniques, novel volumetric computer graphics image analysis and expertise in molecular epidemiology, craniofacial structure, and the genetics of obesity.