title: [Relationship between lower respiratory tract infections in the first year of life and the development of asthma and wheezing in children].
abstract: BACKGROUND
  There is limited knowledge on the relationship between lower respiratory tract infections (LRTI) and asthma and wheezing during infancy, as there are few studies with prospective design, birth cohort and in non selected population. The objectives of the present study were to determine the prevalence of asthma and recurrent wheezing in childhood and to analyse the relationship between LTRI during the first year of life and the development of asthma and/or wheezing in childhood.
  
  
  METHODS
  Prospective birth cohort study conducted in the Hospital del Mar (Barcelona). We recruited 487 children, followed up from the pregnancy to the 6th year of life. As outcomes we studied: the presence of asthma and wheezing. As independent variables we studied: LTRI occurring during the first year of life, and some covariables including, among others: prematurity, birth weight, maternal history of asthma and atopy, breastfeeding, prenatal exposure to tobacco.
  
  
  RESULTS
  The asthma prevalence at 6 year of age was 9.3%. The variables associated with the development of asthma were LTRI, prematurity, atopic mother and formula breastfeeding. LTRI during the first year of life were also related with early recurrent wheezing and persistent wheezing.
  
  
  CONCLUSIONS
  Our results confirm that LTRI during the first year of life are related to the diagnosis of asthma and with the clinical phenotypes of early wheezing and persistent wheezing. These results are in accordance with the concept that LTRI occurring during a critical period of development, as are the first years of life, have an important role on in the later development of asthma and recurrent wheezing.
authors.affiliation: IMIM-Hospital del Mar, Barcelona, España.
authors.forename: Carme
authors.initials: C
authors.lastname: Puig
authors.forename: Bibiana
authors.initials: B
authors.lastname: Fríguls
authors.forename: Mario
authors.initials: M
authors.lastname: Gómez
authors.forename: Oscar
authors.initials: O
authors.lastname: García-Algar
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
authors.forename: Oriol
authors.initials: O
authors.lastname: Vall
mesh_terms: D001249:Asthma / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D015995:Prevalence; D011446:Prospective Studies; D012135:Respiratory Sounds / Q000209:etiology*; D012141:Respiratory Tract Infections / Q000150:complications*