This study tested the hypothesis that obese children are at greater risk of sleep disordered breathing (SDB) than children of normal weight, and that the risk is potentiated by pharyngeal tissue enlargement. 46 obese children (mean (SD) age 10.8 (2.3) years; BMI 27.4 (5.1) kg/m²) and 44 sex and age matched children of normal weight (BMI 18 (1.8) kg/m²) were recruited to a case-control study. Children with known clinical conditions other than obesity were excluded. Two consecutive overnight polysomnographic studies were followed by a daytime multiple sleep latency test, and the size of the upper airway tissues was graded from 0 to 4 by an ENT surgeon. Obstructive apnoea (OA) was defined as the absence of airflow with persistent respiratory effort lasting longer than two baseline breaths (irrespective of Sao₂ changes), and the obstructive apnoea index (OAI) was defined as the number of OA per hour of sleep. Using an OAI of >1 to define SDB, 12 obese children (26.1%) and only one of the normal weight controls (2.3%) had SDB (p = 0.002). SDB was related to a tonsillar size of >2.

The study concluded that the presence of enlarged pharyngeal lymphoid tissue in an obese child should raise the suspicion of SDB, and goes on to suggest an aggressive approach using surgical intervention. Interestingly, the sleep fragmentation and oxygen desaturation seen with SDB were not sufficient to cause an increase in daytime sleepiness and, since only six obese children had tonsils graded >2, further interventional studies would be needed before surgery could be confidently recommended.