title: Risk Factors for Hospitalization for Respiratory Syncytial Virus Infection: A Population-based Cohort Study of Danish Children.
abstract: BACKGROUND
  The aim of this study is to identify the risk factors for hospitalization for respiratory syncytial virus (RSV) infection in Danish children.
  
  
  METHODS
  This is a population-based cohort study with follow-up till 24 months of age. A total of 421,943 Danish children were divided into 5 groups based on gestational age (23-32, 33-35, 36, 37-41 and 42-45 weeks).
  
  
  RESULTS
  In adjusted Cox regression models, chronic disease, asthma hospitalization before the RSV infection and siblings were associated with an increased risk of hospitalization for RSV infection in all children independent of gestational age. Plurality was associated with a decreased risk in children born between 23 and 36 weeks of gestation, whereas young maternal age, maternal asthma, single parenthood, maternal smoking, being born small for gestational age, Caesarian section, male gender and day care were associated with an increased risk of hospitalization for RSV infection in term children. In postterm children, young maternal age, male sex, being born small for gestational age and maternal smoking were associated with an increased risk of hospitalization for RSV. Asthma hospitalization before the RSV infection and siblings were associated with the highest measures of increased risk of hospitalization for RSV infection independent of gestational age.
  
  
  CONCLUSIONS
  By 5 groups of gestational age, we provide estimates of the effects of 12 different factors, which can be regarded as add-on risk factors to those already known to increase the risk of hospitalization for RSV infection. Our study may help clinicians to precisely assess the risk profile in the individual child.
authors.affiliation: From the *The Child and Adolescent Clinic 4072, Copenhagen University Hospital Rigshospitalet; †Research Unit, Women's and Children's Health, The Juliane Marie Centre for Women, Children and Reproduction, Copenhagen University Hospital Rigshospitalet, Copenhagen; ‡Pediatric Department, University Hospital Naestved, Naestved; §Department of Public Health, University of Copenhagen; and ¶Coraxo Consulting, Copenhagen, Denmark.
authors.forename: Ann
authors.initials: A
authors.lastname: Haerskjold
authors.forename: Kim
authors.initials: K
authors.lastname: Kristensen
authors.forename: Mads
authors.initials: M
authors.lastname: Kamper-Jørgensen
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Nybo Andersen
authors.forename: Henrik
authors.initials: H
authors.lastname: Ravn
authors.forename: Lone
authors.initials: L
authors.lastname: Graff Stensballe
mesh_terms: D002675:Child, Preschool; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005865:Gestational Age; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D063868:Patient Outcome Assessment; D011159:Population Surveillance; D012042:Registries; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology* / Q000821:virology*; D018113:Respiratory Syncytial Virus, Human; D012307:Risk Factors