0870 ARE THE CARDIOVASCULAR CONSEQUENCES OF OBSTRUCTIVE SLEEP APNOEA COMPOUNDED BY OBESITY IN CHILDREN?

Abstract

Up to 50% of overweight/obese children have obstructive sleep apnea (OSA) compared to up to 6% of normal weight children. Both obesity and OSA have independent adverse cardiovascular effects, yet, there is limited research into their combined effects in children. This study aimed to compare sleep quality and architecture as well as cardiovascular variables (blood pressure, heart rate, nocturnal dipping) between normal weight and overweight/obese children with and without OSA, and controls. Seventy-four children (8–18 years) referred to the Melbourne Children’s Sleep Centre, and 24 healthy weight non-snoring community controls were recruited. Children were grouped according to their obstructive apnea hypopnea index (OAHI): OSA (>1 event /h) or primary snoring (PS ≤1 event/h) and whether they were healthy weight or overweight/obese (BMI z-score ≥ 1.04): (1) non-snoring healthy weight control group; (2) healthy weight PS group; (3) healthy weight OSA group; (4) overweight/ obese PS group and (5) overweight/obese OSA group. Office blood pressure was recorded whilst awake and heart rate and pulse transit time (PTT) as an inverse surrogate measure of continuous blood pressure recorded continuously during sleep. Sleep quality and architecture were similar between groups. Wake systolic blood pressure was significantly higher in the overweight/obese OSA group compared to the control, healthy weight PS and overweight/obese PS groups (P<0.05 for all). During sleep, blood pressure and heart rate were elevated in the overweight/obese OSA group compared to non-snoring controls (p<0.05). More children who were overweight/obese had reduced dipping of blood pressure and heart rate when asleep compared to healthy weight children. BMI z-score predicted heart rate and PTT when asleep and both age and BMI z-score predicted blood pressure when awake. This study showed that being overweight/obese has independent effects on blood pressure and heart rate in children with OSA. We have previously shown that treatment of OSA reduces blood pressure and suggest that treatment of all severities of OSA in the growing number of overweight/obese children may improve cardiovascular outcomes. The Heart Foundation of Australia (G12M6564), Monash University Strategic Fund and The Victorian Government’s Research Infrastructure Support Program.