Leukocyte telomere length and plasma catestatin and myeloid-related protein 8/14 concentrations in children with obstructive sleep apnea

Background: Obstructive sleep apnea (OSA) is common in children and leads to multiple end-organ morbidities induced by the cumulative burden of oxidative stress and inflammation. Leukocyte telomere length (LTL) reflects not only chronologic age but also the burden of disease. We hypothesized that LTL would be decreased in children with OSA. Methods: Two hundred thirteen children (mean age, 7.7±1.4 years) were included after a sleep study and a morning blood sample. LTL was examined by quantitative polymerase chain reaction in a case-control setting involving 111 OSA cases and 102 controls. Myeloid-related protein (MRP) 8/14 and catestatin plasma levels also were assayed using enzyme-linked immunosorbent assay. Results: Log LTL was significantly increased and OSA severity dependently increased in children (P = .012), was positively associated with apnea-hypopnea index (AHI)(r = 0.236; P < .01), and was inversely correlated with age(r = -0.145; P < .05). In a multivariate regression model, LTL was independently associated with AHI (β = 0.28; P = .002) after adjusting for age, sex, BMI z score, and race. Children with OSA exhibited higher BP(P < .05), lower plasma catestatin (P = .009), and higher MRP 8/14 levels(P < .001) than controls. Of note, children with the lowest plasma catestatin levels (<1.39 ng/mL) had 5.2-fold increased odds of moderate-to-severe OSA (95% CI, 1.19-23.4 ng/mL; P < .05) after adjusting for confounding variables. Conclusions: In pediatric OSA, LTL is longer rather than shorter. Children with OSA have reduced plasma catestatin levels and increased BP along with increased MRP 8/14 levels that exhibit AHI dependencies. Thus, catestatin and MRP 8/14 levels may serve as biomarkers for cardiovascular risk in the context of pediatric OSA. However, the implications of increased LTL in children with OSA remain to be defined.