ESPE Abstracts

Introduction: Obstructive sleep apnea (OSA) affects up to 40% of children and adolescents with obesity and the risk for OSA is directly correlated with obesity severity. Several studies have pointed out that OSA per se might lead to metabolic derangement including worsening of insulin resistance, hyperglycemia, and hepatic steatosis. However, the pathophysiologic mechanisms underpinning these associations remain unclear, especially in pediatric groups. The main purpose of the study is to assess the association between OSA and insulin clearance in children and adolescents with obesity.

Methods: We retrospectively enrolled children and adolescents who attended our pediatric clinic because of obesity and suspected OSA. Glucose homeostasis was assessed through a 3-hour oral glucose tolerance test (OGTT). Nocturnal cardio-respiratory polygraphy was performed for OSA diagnosis. Insulin secretion rate (ISR) was estimated by C-peptide deconvolution. Endogenous insulin clearance was calculated as the ratio between fasting ISR and plasma insulin levels (ISR_fast/I_fast) and as the ratio of their areas under the curve (AUC) over the duration of the OGTT (ISR_AUC/ I_AUC). Whole-body Insulin sensitivity was assessed according to the Matsuda Index (WBISI). The hepatic insulin resistance index (HIRI) was calculated as the product of the AUCs of plasma glucose and plasma insulin during the first 30 minutes of the OGTT (Glucose AUC_0–30 × Insulin AUC_0–30).

Results: Seventy-one children were included in the study. Based on OSA severity, the cohort was divided into two groups (39 mild and 32 moderate-severe OSA). The two groups did not differ in age, gender, and BMI z-score distribution (all P >0.05). The group with moderate-severe OSA showed higher HIRI (P = 0.02) and lower insulin clearance after oral glucose (P = 0.02). No differences were observed for basal insulin clearance (P = 0.66), insulin secretion (P = 0.34), insulin sensitivity (P = 0.69), and glucose sensitivity (P = 0.34). OSA severity was positively correlated with HIRI (r =0.25, P = 0.03) and there was a trend for a correlation between OSA and insulin clearance during OGTT (r = -0.20, P = 0.09).

Conclusion: These findings suggest that OSA impairs hepatic insulin sensitivity and clearance in children and adolescents with obesity. The interrelation between sleep apnea and liver damage should be more deeply investigated to better clarify the underlying mechanisms.