Objectives: A high proportion of children with Down syndrome (DS) have the obstructive sleep apnea syndrome (OSAS). Although adults with DS have many predisposing factors for OSAS, this population has not been well studied. We hypothesized that OSAS is common in adults with DS, and that the severity of OSAS is worse in DS adults who are more obese.
Design: Cohort study.
Setting: Sleep laboratory.
Participants: 16 adults with DS underwent evaluation for sleep disordered breathing.
Interventions: Polysomnographic results were compared to a retrospective sample of adult patients referred for clinically suspected OSAS.
Measurements and results: Polysomnograms were abnormal in 94% of DS subjects. The median apnea hypopnea index (AHI) was 37/h (range 0-118). The median arterial oxygen saturation nadir was 75% (23% to 95%), and the median peak end-tidal CO2 was 58 (47-66) mm Hg. There was a significant correlation between body mass index and AHI (r = 0.53, p < 0.05). Sixty-three percent had an Epworth score > 10. The AHI and saturation nadir were significantly worse in DS than non-DS patients.
Conclusions: Adults with DS frequently have OSAS, with obstructive apnea, hypoxemia, hypoventilation, and sleep fragmentation. The severity of OSAS correlated with obesity. We speculate that the complications of untreated OSAS (cardiovascular disease, increased mortality, and neurobehavioral morbidities including daytime sleepiness and impaired cognitive function) commonly overlap with the manifestations of DS and therefore may not elicit a prompt investigation in these patients. We speculate that OSAS is an important, but potentially treatable, cause of morbidity in adults with DS.