Nocturnal arterial oxygen saturation and academic performance in a community sample of children

Objective. Hypoxemia, often assessed via pulse oximetry, is associated with neurocognitive deficits in children. The best way to qualify hypoxemia, or which level of hypoxemia already affects cognition, is unknown. Methods. We assessed the association of pulse oximetry - derived variables that qualify hypoxemia with impaired academic performance in mathematics in a population-based cross-section of 995 primary school children who underwent overnight home recordings of motion-resistant new-generation pulse oximeter saturation (SpO(2)). Impaired academic performance in mathematics was based on the last school report and defined as grade 4 to 6 on a 6-point scale (ie, approximately the lowest quintile grades). Results. Of 10 variables under study, only the nadir of the SpO(2) values was significantly associated with impaired performance. Categories of this variable representing mild (ie, 91% - 93% SpO(2); odds ratio: 1.65; 95% confidence interval: 1.06 - 2.56) and moderate hypoxemia (ie, less than or equal to 90% SpO(2); odds ratio: 2.28; 95% confidence interval: 1.30 - 4.01) both were associated with impaired performance in mathematics. Conclusions. We suggest using the nadir of the SpO(2) values in an overnight study to qualify hypoxemia in future studies. This variable may predict neurocognitive deficits in school children. Mild hypoxemia, as yet widely considered benign, may already affect cognition in childhood.