Plasma IGF-1 levels and cognitive dysfunction in children with obstructive sleep apnea

Background: Pediatric OSA is associated with substantial morbidity in cognitive function. However, for any given OSA severity level, altered cognitive performance may or may not be present. Since IGF-1 is neuroprotective, we hypothesized that higher systemic IGF-1 levels may identify children at lower susceptibility for cognitive morbidity. Methods: Consecutive habitually snoring and non-snoring children ages 5-7 years were recruited from the community, and underwent overnight polysomnography, and neurocognitive testing and a blood draw the next morning. Snoring children were divided into OSA or no OSA, and OSA children were further subdivided into those with ≥2 abnormal cognitive subtests and into those with normal cognitive scores. Plasma levels of IGF-1 were also measured using ELISA. Results: Among snoring children without OSA, circulating IGF-1 was 910 ± 110 pg/mL compared with 1070 ± 240 pg/mL in those with OSA (p < 0.01). However, IGF-1 was 540 ± 70 pg/mL in children with OSA and cognitive deficits, compared to 1370 ± 170 μg/L in children with OSA and normal cognitive scores (p < 0.001). Conclusions: IGF-1 levels are higher in children with OSA, particularly in those who do not manifest neurocognitive deficits, suggesting that the magnitude of the IGF-1 response elicited by OSA may play a significant protective role against the neurocognitive dysfunction associated with OSA.