FAMILIAL AGGREGATES IN OBSTRUCTIVE SLEEP-APNEA SYNDROME

Obstructive sleep apnea syndrome (OSAS) was diagnosed in 157 subjects based on clinical symptoms, physical evaluation, cephalometric x-ray f ilms, and polysomnography. These index cases identified 844 living fir st-degree relatives. Mailings were sent to 792 (94%). The mailing cons isted of two identical questionnaires, one for the family member of th e index case and one to be given to a friend (not a relative) of appro ximately the same age. In response, we received 531 (63%) questionnair es from relatives and 198 (25%) questionnaires from age-matched nonrel ated friends, which were used as a control group. A more extensive inv estigation was performed on first-degree relatives of the index group living in the San Francisco Bay Area or vicinity. Two hundred seventy- nine relatives (100%) were identified. One hundred sixty-six subjects (59%) as well as 69 age-matched friends (ie, 41% of the 166 relatives and 25% of the potential total group) agreed to participate in further studies. These subjects had interviews, clinical investigations, and nonattended ambulatory monitoring. Cephalometric x-ray films could be obtained on only 22 of 166 participating relatives and 6 of 69 friends . Body mass index was not a differentiating measure between relatives and friends. Odds ratios (ORs) were calculated from the questionnaire data. The report of tiredness, fatigue, and sleepiness did not disting uish family members from friends. The OR, however, progressively incre ases when there is a positive history of near nightly loud snoring (OR =1.78; 95% confidence interval [CI] 1.25-2.54) or a positive history o f daytime sleepiness in conjunction with near nightly loud snoring (OR =3.11; 95% CI=1.94-4.99). The investigation in the Bay Area indicated that, when first-degree relatives were compared with friends, the comp laint of daytime tiredness, sleepiness, or both with the presence of a high and narrow (ogival) hard palate sharply differentiated between f riends and relatives (OR=10.9, 95%, CI=5.31-22.5). An Epworth Sleepine ss Scale score of 9 or greater with the presence of another symptom as sociated with OSAS, and a respiratory disturbance index greater than 5 (number of apneas and hypopneas per hour of sleep >5) gave an OR of 4 5.6 (95% CI=18.8-11.0). Disproportionate craniofacial anatomy was comm on in familial groups with OSAS. Craniofacial familial features can be a strong indicator of risk for the development of OSAS.