Objective: To identify risk factors which may lead to the occurrence of recurrent wheezing in children under five years of age.

Material and Method: A cross-sectional study was conducted in children under 5 years old at the Out Patient Department at Naresuan University Hospital, from October 2013 to October 2014. Fifty-five children who had signs and symptoms of recurrent wheezing were assigned to the study group, whereas another fifty-five children matching on age and sex with the case who had no symptoms of recurrent wheezing were assigned to the control group. All of the parents completed the given questionnaires. Descriptive data analysis were statistically conducted to understand the characteristics of the study groups. The risk factors were analysed using both bivariate and multivariate statistical analyses which included all the important predictors with a statistically significant level of p<0.05.

Results: Mean age in the study group was 36.1 months and in the control group 25.0 months. The mean weights and heights showed no difference between the case and control groups. Bivariate analysis showed that upper respiratory tract infection [odds ratio (OR) 7.273; 95% confidence interval (CI) 2.277-23.232)], lower respiratory tract infection (OR 5.332; 95% CI 2.326-12.225), passive smoking (OR 2.368; 95% CI 1.094-5.129), and day care center attendance (OR 2.590; 95% CI 1.168-5.745) were the risk factors of recurrent wheezing. Multivariate logistic regression analysis indicate that lower respiratory tract infection [adjusted odds ratios (aOR) 0.241; 95% CI 0.088-0.659] was the most important risk factor leading to recurrent wheezing.

Conclusion: Lower respiratory tract infection, upper respiratory tract infection, passive smoking and day care center attendance were found to be risk factors of recurrent wheezing in children under five years of age, with lower respiratory tract infection being the most risk. Targeted surveillance of these risk factors should reduce the incidence of recurrent wheezing. This is especially important for high risk patients such as asthma patients.

Keywords: Recurrent wheezing, risk factors, asthma, lower respiratory tract infection, respiratory tract infection