Risk factors and natural history of habitual snoring.

STUDY OBJECTIVE It has been suggested that habitual snoring (HS) has adverse health outcomes in children. We aimed to identify risk factors for HS and determine its natural history in primary school children. DESIGN Cross-sectional, population-based cohort study. SETTING Twenty-seven primary schools located within the city limits of Hannover, Germany. PARTICIPANTS Third-grade primary school children. MEASUREMENTS AND RESULTS Snoring frequency and potential risk factors were investigated using parental questionnaires. Unadjusted and adjusted odds ratios (ORs) for HS and their 95% confidence intervals (CIs) were calculated. One year after the initial contact, snoring status was re-evaluated in habitual snorers. In total, 1,760 children were contacted, and 1,144 parents and their children (49% were girls) agreed to participate and returned a completed questionnaire. A body mass index >/= 90th percentile (OR, 3.5; 95% CI, 1.8 to 7.1), low maternal education (OR, 2.3; 95% CI, 1.1 to 4.7), regular daytime mouth breathing (OR, 7.4; 95% CI, 3.5 to 15.6), and a higher frequency of sore throats (OR, 17.6; 95% CI, 6.4 to 48.8) were independent risk factors for HS. Parental smoking and frequent infections were significantly but not independently associated with HS. The association of low maternal education and HS was higher in boys (OR, 4.4; 95% CI, 1.5 to 13.6; vs OR, 1.2; 95% CI, 0.4 to 3.6), while that of sore throats and HS was higher in girls (OR, 52.7; 95% CI, 6.0 to 460.2; vs OR, 13.3; 95% CI, 3.0 to 58.5). At follow-up, 39 of 80 eligible habitual snorers (48.8%) still snored regularly. Children who continued to snore differed significantly in maternal education, household smoking, snoring loudness, and prior ear, nose, throat surgery from those who had ceased to snore habitually. CONCLUSIONS Socioeconomic status, obesity, signs of nasal obstruction, and pharyngeal problems were independent risk factors for HS in these primary school children. The expression of HS varied considerably over time.