Sleep-disordered breathing and pulmonary function in obese children and adolescents

Obese children have an increased risk of developing obstructive sleep apnea syndrome (OSAS) compared to normal-weight children. In obese children, OSAS is more frequently associated with oxygen desaturations, which might be caused by pulmonary function abnormalities. Our goal was to investigate the association between OSAS and pulmonary function in obese children and adolescents.

There were 185 children included and distributed in groups based on their obstructive apnea-hypopnea index (151 controls, 20 mild OSAS, and 14 moderate-to-severe OSAS). All subjects underwent polysomnography and pulmonary function testing.

Several differences in pulmonary function were observed between groups. Vital capacity (VC) and forced expired volume in 1s (FEV1) were significantly decreased in patients with moderate-to-severe OSAS, as were expiratory reserve volume (ERV), total lung capacity, and functional residual capacity (FRC). Correlations between FEV1, FRC, and ERV with OSAS severity remained significant independent of the degree of adiposity. Correlations between FEV1/VC and sleep-related respiratory parameters did not persist after correction for adiposity.

An association between awake pulmonary function and sleep-related respiratory parameters could be observed in our population of obese children. These results suggest that OSAS severity is correlated with a diminished lung function. However, the level of obesity remains an important confounding factor in both OSAS severity and pulmonary function.