Riikonen R, Korppi M, Törmänen S, et al. - Because there is growing evidence that environmental factors in childhood play a role in the development of irreversible airway obstruction, researchers sought to assess early-life and preschool-age risk factors for irreversible airway obstruction in adolescence after bronchiolitis in infancy. Data on risk factors were collected during hospitalisation and on follow-up visits at the ages of 5–7 and 10–13. Lung function was measured in 103 participants aged 5–7 years using impulse oscillometry and 89 participants aged 10–13 years using flow-volume spirometry. Asthma diagnosis during the first year of life, as well as poor lung function in preschool, increased the risk of irreversible airway obstruction after bronchiolitis at 10–13 years of age. TLR4 rs4986790 polymorphism may be protective against the development of irreversible airway obstruction following bronchiolitis.