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 25s 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.