Respiratory infections in schoolchildren: co-morbidity and risk factors.

AIMS To assess co-morbidity and risk factors for otitis media, tonsillopharyngitis, and lower respiratory infections in school children. METHODS Logistic regression analysis of co-morbidity and risk factors for airway infections in a population based sample of 10 year old children living in Oslo, Norway. MAIN OUTCOME MEASURES otitis media, tonsillopharyngitis, and lower respiratory infections in past 12 months. RESULTS Airway infections in 10 year old children were common, and significant co-morbidity was found between the various airway infections. Home dampness was a risk factor for all infections, adjusted odds ratios ranging from 1.2 (95% CI 1.0 to 1.5) to 1.4 (95% CI 1.1 to 1.6) for otitis media and tonsillopharyngitis respectively. Atopic disease was a constitutional risk factor, particularly strong for lower airway infections (adjusted odds ratio 2.4, 95% CI 1.8 to 3.1). African or Asian ethnicities were associated with the airway infections, adjusted odds ratios ranging from 1.2 (95% CI 0.9 to 1.7) to 1.7 (95% CI 1.2 to 2.3). CONCLUSIONS Respiratory tract infections were common in 10 year old children. There was substantial co-morbidity between upper and lower airway infections. Environmental and constitutional factors were identified and positively associated with the infections. Results support the hypothesis of 1957 that the whole respiratory tract is one unit.