Abstract â–¡ 3

During a ten year period, three hundred and forty-eight infants aged three weeks to three months were referred to Stanford Sleep Clinic for "apparent life threatening events" or suspicion of sleep disordered breathing. These infants had clinical and polygraphic information systematically collected, with researchers following a pre-established clinical protocol. We recruited 48 infants of the same age group from the same community who did not have any positive history of sleep-related breathing disorders to serve as controls for research purposes. The control infants were submitted to the same clinical evaluation before entering the research protocol.

We conducted a systematic investigation of relatives (parents, siblings, and grandparents) of the infants. The investigation involved a clinical evaluation, with a physical, investigation of medical and medication-intake history, cranio-facial investigation using simple clinical scales, and completion of an extensive (189 questions) validated sleep/wake questionnaire. When first-degree relatives could not come to the clinic, the questionnaire was the sole source of information.

The referred infants were 79% Caucasian, 12% African-American, 8% Hispanic, and 0.6% Asian. A total of 96.7% of parents, 71% of grandparents, and 97.8% of siblings were examined, and questionnaires alone were obtained from an additional 14% of grandparents.

At the conclusion of the clinical work-up, it was determined that 148 referred infants (42.5%) had no sleep disordered breathing (Group A). There was an overwhelming presence of relatives of infants with sleep disordered breathing (Group B) who also had symptoms and signs of sleep disordered breathing. This high dominance was also obvious when frequency of treatment for sleep disordered breathing (usage of nasal CPAP, surgical and dental appliance treatments) was compared (43.3% versus 7.1% of Group A relatives). Clinical investigation indicated the presence of small upper airways in the families of index cases where sleep disordered breathing was seen during early infancy. There were also about twice as many relatives who reported presence of asthma in Group B as compared to Group A.