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. PM_2.5 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. PM_2.5 concentrations were monitored hourly using air quality monitors utilizing light-scattering technology. The geometric means of daily mean PM_2.5 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.