Ambient temperature, air pollution and childhood bronchiolitis

Acute bronchiolitis is one of the main causes of lower respiratory infection-related hospitalisations among young children and is often attributed to infection with respiratory syncytial virus (RSV). Seasonality of RSV infection has been reported in different climatic regions, with a higher incidence in winter in temperate regions and in the rainy season in areas closer to the equator.1 Ambient exposures, such as meteorological factors and air pollutants, that affect host susceptibility, survival of pathogen and transmission may partly drive the seasonality of acute bronchiolitis, but these have been less widely investigated when compared with other common childhood respiratory conditions such as asthma. In subtropical regions, seasonality in acute childhood bronchiolitis has been reported by a number of studies, but few investigated this in relation to environmental exposures. The report in this issue by Leung et al makes a start in filling in some of these knowledge gaps.2 In a well-conducted time series regression study, they investigated the association of meteorological factors and air pollutants on daily childhood (≤2 years old) acute bronchiolitis hospitalisations over a 10-year period in the subtropical metropolitan setting of Hong Kong. The study analysed data from 12 …