Peak flow rate and its association with asthma, respiratory symptoms and weekly ambient air pollutants among 14 years old schoolchildren in Malaysia

Abstract

Introduction: This cross sectional study aims to investigate the associations between peak flow rate and demographic factors, respiratory symptoms and weekly ambient air pollutants among schoolchildren (n=487) in Malaysia. Methods: Information on health were collected using the ISAAC related-questionnaire, and peak flow rate among the 14 year old schoolchildren were taken using the Sibelmed’s peak flow meter from Spain. Bivariate and multivariate analyses were done to identify the associations and risk factors for peak flow rate. Results: Overall peak expiratory rate of the schoolchildren were 329 L/min +-SD 55 L/min (minimum 180 L/min and maximum 560 L/min). Schoolchildren’s demographic data showed that gender (p<0.000), school’s exposure (p=0.001) and smoking status (p<0.000) were associated with peak flow rate. However, respiratory symptoms (wheezing and whistling, ever had asthma, doctor-diagnosed asthma, daytime and nocturnal breathlessness, current asthma and current airway infection) were not associated with peak flow rate. Peak flow rate was significantly correlated with weekly mean ambient air pollutants, CO (r=-0.134, p=0.003), O3 (r=-0.157, p=0.001), NO2 (r=0.145, p=0.001) and temperature (r=0.127, p=0.005). Multivariate regression analysis, shows that gender (R2=0.175) (beta=0.399,p <0.000), weekly mean O3 (R2=0.200) (beta=-0.189, p<0.000), weekly mean SO2 (R2=0.217) (beta=-0.128, p=0.002), and smoking status (R2=0.227) (beta=0.106, p=0.012) were predictors in peak flow rate after adjusting for other confounders. Conclusion: Schoolchildren’s lung function is linked with their demographic factors and weekly air pollutants but not respiratory symptoms. Peak flow rate could be considered a useful tool in lung function studies among Malaysian schoolchildren who are exposed to air pollutants. However, the duration of exposure to ambient air pollutants among the schoolchildren should be further analyzed.