Hypoxic Burden Is an Important Determinant of Height in Nonobese Children With Sleep-Disordered Breathing

The relationship between linear growth and obstructive sleep-disordered breathing (SDB) has not been extensively studied. Hypoxic burden (HB) is a new metric that may better capture end-organ damage in paediatric SDB compared to the traditional apnea-hypopnea index (AHI). This observational cross-sectional study examined the association between HB and linear growth in nonobese children aged 3-9 years with SDB. HB was assessed as the area under the peripheral oxygen desaturation curve, alongside standard polysomnography indices. A cohort of 164 children without comorbidities except for asthma was evaluated for suspected SDB, with demographic and anthropometric data collected. The mean ± standard deviation height z score was -0.05 ± 1.09, and the median [25th; 75th percentile] HB was 1.4 [0.4; 3.5] %min/h. Forty children (24%) had an obstructive AHI greater than 5/h. HB and frequent snoring (≥ 3 nights/week) were significantly and negatively associated with height z score (standardized β = -0.21, p = 0.036 and -0.37, p = 0.043, respectively), whereas AHI did not predict linear growth outcomes. In multivariate analyses, HB remained independently associated with lower height z score and accounted for 7.5% of its variance, compared with 12.7% for ethnicity and 6.4% for body mass index z score. The oxygen desaturation index was also a significant predictor, but it explained less variance in height z score than HB. These findings suggest that intermittent hypoxia may contribute to impaired linear growth in children with SDB, although its contribution is modest and other determinants of growth remain important.