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.