Hypobaric and intermittent hypoxia in pediatric OSA: Associations with cardiac stress.

OBJECTIVE: To examine whether obstructive sleep apnea (OSA) is associated with pro-B-type natriuretic peptide and its N-terminal fragment (proBNP/NT-proBNP), a blood marker of myocardial wall stress, and with echocardiographic measures of cardiac size and function in children living at high altitude. METHODS: 274 children aged 5-16 years living in Bogotá, Colombia (2660 m) underwent overnight polysomnography, from which OSA and hypoxic-burden measures (oxygen desaturation index, percentage of sleep time with oxygen saturation below 90%) were derived. Serum proBNP/NT-proBNP and interleukin-10 (IL-10, an anti-inflammatory cytokine) were measured by enzyme-linked immunosorbent assay, and pediatric cardiologists performed echocardiography. STATISTICAL ANALYSIS: proBNP/NT-proBNP was analysed with median regression adjusted for sex and body mass index z-score; six echocardiographic outcomes were tested with Holm correction; hypoxic-burden and IL-10 analyses were exploratory. RESULTS: 187 (68%) children had OSA. Median proBNP/NT-proBNP was higher with OSA (adjusted ratio of medians 1.56, 95% confidence interval 1.02-2.39). No echocardiographic outcome differed after correction (all Holm-adjusted p ≥ 0.14). In exploratory analyses, a higher oxygen desaturation index was associated with higher proBNP/NT-proBNP (p = 0.014), but this did not remain after false-discovery-rate correction (q = 0.22). IL-10 analyses were exploratory. CONCLUSIONS: In children living at 2660 m, OSA was associated with higher proBNP/NT-proBNP but not with echocardiographic differences. Longitudinal, multi-altitude studies are needed.