Exposure to nitrogen dioxide and respiratory health at 2 years in the INMA-Valencia cohort

Objective: To analyze the association between exposure to nitrogen dioxide (NO2) during pregnancy and the postnatal period up to the age of 2 years old and the incidence of respiratory problems in children from the INMA-Valencia cohort. Methods: The study population included 624 children from the INMA-Valencia cohort. Individual exposure to NO2 was estimated in different environments outside the home during pregnancy and up to the age of 2 using empirical measurement and data from geo-statistical methods. Respiratory symptoms were obtained from a questionnaire applied at the age of two. The association between NO2 exposure and respiratory symptoms was performed using multivariate logistic regression. Results: The cumulative incidence was 16.3% for persistent cough, 34.9% for wheezing and 27.6% for lower respiratory tract infections. No association was found between respiratory symptoms and exposure to NO2 in any of the children. However an association between NO2 exposure and persistent cough was found at two years of life in the children with a parental history of allergy. Conclusion: NO2 exposure would lead to persistent cough in children with a parental history of allergies. (C) 2017 SESPAS. Published by Elsevier Espana, S.L.U.