Prevalence and risk factors of chronic cough in Swiss schoolchildren

Abstract

Introduction: Population-based studies on chronic cough in children are scarce. Little is known on how chronic cough varies by sex, age and presence or absence of wheeze, and its risk factors are unclear. Methods: In 2013-16, we conducted a field study on respiratory health among schoolchildren in the canton of Zurich, Switzerland (“Luftibus in the school”). Parents and children completed a questionnaire, and lung function tests were done in a mobile lab. In the questionnaire chronic cough was defined as cough lasting more than 3 weeks. We performed a multivariable logistic regression to identify factors associated with chronic cough. Results: We analysed data from 3395 children (age range 6-17 years, 50% girls), of which 319 (9%) reported chronic cough. The prevalence was 10% in girls, 8% in boys, 12% in 6-9 years old and 8% in older children. 73 (23%) of those with chronic cough reported also wheeze. Factors associated with chronic cough in the multivariable regression were: female sex (OR 1.5, 95%CI 1.1-2.0), younger age (OR:1.1, 95%CI 1.0-1.2), overweight (OR 1.5, 95%CI 1.1-2.1), active smoking (≥1/week) (OR 4.1, 95%CI 1.7-10.0), asthma (OR 2.6, 95%CI 1.8-3.9), rhinitis (OR 1.8, 95%CI 1.3-2.5) and otitis media (OR 1.9, 95%CI 1.3-2.7). We found no association with number of siblings, parental smoking, living on a farm, pets, hay fever and snoring. Conclusion: Chronic cough is frequent among schoolchildren in Switzerland, especially girls and younger children and associated with asthma and upper respiratory disease. Overweight and smoking are modifiable risk factors which could be addressed to reduce the burden of chronic cough. Funding: Lunge Zurich, SNF:32003B_162820