Pulmonary function and sleep-related breathing disorders in severely obese children

Background & aims To evaluate the frequency of pulmonary function and sleep-breathing disorders in severely obese children and to search for their association with obesity phenotypes. Methods Sleep studies and spirometry were performed for 54 severely obese children. Results Upper airway resistances (RAWs) were increased with RAW>200% and forced 25 s expiratory volume<80% in 83% and 60% of individuals, respectively. A decrease in functional residual capacity (FRC)<80% was found in 43%. Fifty-two percent of the children had a desaturation index>10 during sleep, and 41% of children presented at least one of three severity criteria (snoring index>300 per hour, respiratory events index (REI)>10 and arousal index>10). Univariate analyses showed a positive correlation between snoring index and BMI Z-score and neck/height ratio (P=0.01 and 0.04, respectively) as between REI and the same parameters (P=0.01 and 0.03, respectively). In a multivariate model with BMI Z-score, NHR still correlated with the snoring index (P=0.02) and REI (P=0.01). Conclusions In our cohort, obese children showed frequent pulmonary function and sleep-breathing disorders. The later were associated with impaired upper airway respiratory conductance.