Aims: We examined the natural history of mild childhood obstructive sleep apnoea (OSA) and identified factors that were associated with disease progression.
Methods: Subjects were recruited from an epidemiological study which examined the prevalence of OSA in Chinese children aged 6 to 13-year-old. The first 56 consecutive children identified to have mild OSA (apnoea-hypopnoea index, OAHI, 1-5) were invited for repeat assessment 2 years after the diagnosis.
Results: Forty-five children participated in this follow-up study, of whom 13 subjects (29%) were identified to have worsened OSA. When compared to those without worsening of OSA, the worsened OSA group had a greater increase in waist circumference, a higher prevalence of large tonsils (occupied ≥50% of the airway) at both baseline and follow-up, and a higher prevalence of habitual snoring at both baseline and follow-up. The presence of large tonsils had a positive predictive value of 53% and a negative predictive value of 83% for worsening OSA over a 2-year period. Multivariate linear regression analysis showed that the change in OAHI was associated with age at baseline [β(SE)=-0.92(0.34), p=0.009], gender (male=1; female=0) [β(SE)=4.69(1.29), p<0.001], presence of large tonsils at baseline [β(SE)=4.36(1.24), p=0.001], change in waist circumference [β(SE)=0.30(0.09), p=0.002] and persistently large tonsils [β(SE)=5.69(1.36), p<0.001] over the 2-year period.
Conclusions: Mild OSA in majority of children did not resolve spontaneously. Cases with tonsillar hypertrophy, especially for boys, should be closely monitored to allow early detection of OSA worsening. Weight control should be stressed in the management of childhood OSA.