RESUMO
BACKGROUND: Up to 50% of overweight/obese children have obstructive sleep apnea (OSA) compared to up to 6% of normal weight children. We compared cardiovascular variables between normal weight and overweight/obese children with and without OSA, and controls. METHODS: Seventy-four referred children and 24 normal weight non-snoring controls (8-18 years) were recruited. Referred 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 normal weight (BMI z-score <1.04) or overweight/obese (BMI z-score ≥ 1.04). Wake blood pressure (BP), heart rate (HR), and pulse transit time (PTT, an inverse continuous surrogate measure of blood pressure) during sleep were recorded. RESULTS: Wake BP was higher in the overweight/obese OSA group than in the control, normal weight PS, and overweight/obese PS groups (p < 0.05 for all). During sleep, BP, and HR were elevated in the overweight/obese OSA group compared to those in non-snoring controls (p < 0.05). More children who were overweight/obese had reduced BP and HR dipping from wake to sleep than normal weight children. The BMI z-score predicted HR and PTT when asleep and both age and BMI z-score predicted BP when awake. CONCLUSION: This study showed that BMI has both combined and independent effects on BP and HR in children with OSA. We have previously shown that treatment of OSA reduces BP and suggest that treatment of OSA in the growing number of overweight/obese children may improve cardiovascular outcomes.