The influence of home and out-of-school factors on respiratory symptoms among schoolchildren in Ho Chi Minh City, Vietnam.

This cross-sectional study examined the one-year prevalence of respiratory symptoms (RS) and the influence of home and out-of-school factors among 1,033 schoolchildren (aged 9-12) in Ho Chi Minh City (HCMC), Vietnam. PM2.5 levels were also monitored in schools near major roads and residential areas. Near major roads and in residential areas the prevalence of wheezing was 20.6% and 16.9% and that of rhinitis 55.7% and 61.5%, respectively. Neither differed significantly between areas. PM2.5 concentrations were monitored hourly using air quality monitors utilizing light-scattering technology. The geometric means of daily mean PM2.5 concentration in schools adjacent to a major road and schools within the residential area were 61.2 μg/m3 and 31.0 μg/m3, respectively (p < 0.001). After adjustment for confounding, positive associations (aOR [95% CI]) of wheezing and rhinitis, respectively, were seen with exposure to secondhand smoke (1.70 [1.21-2.39] and 1.67 [1.27-2.19]), frequent truck traffic (1.97 [1.22-3.17] and 1.61 [1.13-2.28]), daily traffic congestion (1.57 [1.10-2.22] and 1.33 [1.03-1.73]) and participation in extra classes (1.71 [1.24-2.35] and 1.37 [1.07-1.76]). Wheezing alone was associated with nightly air conditioning use (2.27 [1.47-3.49]) and residential proximity to factories (1.72 [1.10-2.71]). Targeted interventions are needed to improve air quality in both school and home environments in HCMC.