Prevalence and persistence of sleep disordered breathing symptoms in young children: a 6-year population-based cohort study

Study objectives: To describe the prevalence, persistence, and characteristics associated with sleep disordered breathing (SDB) symptoms in a population-based cohort followed from 6 months to 6.75 years.

Design: Avon Longitudinal Study of Parents and Children (ALSPAC).

Setting: England, 1991-1999.

Participants: 12,447 children in ALSPAC with parental report of apnea, snoring, or mouth-breathing frequency on any one of 7 questionnaires.

Measurements: Symptom prevalence rates-assessed as "Always" and "Habitually"-are reported at 0.5, 1.5, 2.5, 3.5, 4.75, 5.75, and 6.75 years of age. The proportion of children in whom symptoms develop, persist or abate between observation points is reported. Exploratory multivariate analyses identified SDB risk factors at 1.5, 4.75, and 6.75 years.

Results: The prevalence of apnea ("Always") is 1%-2% at all ages assessed. In contrast, snoring "Always" ranges from 3.6% to 7.7%, and snoring "Habitually" ranges from 9.6% to 21.2%, with a notable increase from 1.5- 2.5 years. At 6 years old, 25% are habitual mouth-breathers. The "Always" and "Habitual" incidence of each symptom between time points is 1%-5% and 5%-10%, respectively. In multivariate analyses of combined symptoms, socioeconomic factors have stronger, more persistent effects upon increased SDB risk than gestational age, gender, or race (aside from 1.5 years); adenoidectomy decreases risk by 40%-50%.

Conclusions: This is the first natural history study of the primary symptoms of SDB across a key 6-year period in the development of SDB symptoms. Snoring rates are higher and spike earlier than previously reported. Symptoms are dynamic, suggesting the need for early and continued vigilance in early childhood.