Lead researcher
Prof Rosemary Horne
Main finding
Being overweight or obese in childhood has significant effects on health. This is of concern as rates of childhood obesity are rising worldwide, with nearly a quarter of Australian children falling into this category. Up to half of all overweight children also snore when they are asleep. Both being overweight and snoring, which is the cardinal symptom of obstructive sleep apnoea, have adverse effects on the heart and blood pressure. Children with obstructive sleep apnoea have more than one pause in breathing or apnoea per hour of sleep and often many pauses in breathing during the night, whereas those with snoring have less than one apnoea per hour. We found that those children who were both overweight and had obstructive sleep apnoea had higher blood pressure when they were awake and also when they were asleep. In addition, fewer overweight children with obstructive sleep apnoea had the normal fall in heart rate and blood pressure which occurs when you go to sleep. This is important as this lower blood pressure and heart rate when you are asleep allows your cardiovascular system to 'rest'.
Centre
The Ritchie Centre
Research group
Paediatric Sleep
Journal and article title
Most surprising
This was the first study to separately examine the effects of being overweight and having obstructive sleep apnoea. We studied five groups of children: normal weight children who didn't snore; normal weight children who snored but didn't have obstructive sleep apnoea; normal weight children who had obstructive sleep aonoea; overweight/obese children who just snored and overweight/obese children who had obstructive sleep apnoea. We found that weight predicted blood pressure when both awake and asleep and that the effects of being overweight and having obstructive sleep apnoea were additive on blood pressure when both awake and asleep.
Future implications
We have shown that treatment of obstructive sleep apnoea lowers blood pressure. In those children with severe disease, surgery is recommended to remove enlarged tonsils and adenoids which can block the airway when asleep, while in those with milder disease anti-inflammatory medications are often recommended. It is important to treat children with snoring and obstructive sleep apnoea, particularly those who are overweight, as both high blood pressure and obesity track into adulthood and can lead to more serious cardiovascular complications.
Disease/health impact
obesity, obstructive sleep apnoea
