Objective: To determine whether familial factors affect development of the sleep apnea–hypopnea syndrome and upper airway caliber.
Design: A case–control study.
Setting: Tertiary, referral clinical sleep laboratory.
Participants: 51 first-degree relatives of patients with the sleep apnea–hypopnea syndrome and 51 controls matched for age, sex, height, and weight who were drawn at random from a family practice register. To avoid studying the familial nature of obesity, only relatives of index patients with body mass indices less than 30.0 kg/m2 were recruited.
Measurements: Assessment of sleep-related symptoms; breathing, sleep, and oxygenation patterns on overnight polysomnograms; upper airway dimensions by acoustic reflection; and facial structure by lateral cephalometry.
Results: More relatives of patients with the sleep apnea–hypopnea syndrome reported snoring (24 relatives compared with 7 controls; P < 0.001) and daytime sleepiness (28 relatives compared with 16 controls; P = 0.01). Relatives had more apneas and hypopneas per hour (median of 13/h [95% CI, 3 to 82/h] for relatives compared with median of 4/h [CI, 0 to 53/h] for controls; P < 0.001), more arousals from sleep (30/h [CI, 11 to 87/h] for relatives compared with 17/h [CI, 4 to 59/h] for controls; P <0.001), poorer sleep quality, and more oxygen desaturations. Relatives also had narrower upper airways with retroposed maxillae and mandibles and longer soft palates with wider uvulae.
Conclusion: The sleep apnea–hypopnea syndrome has a strong familial component. The familial tendency may be caused by differences in facial structure.