title: The role of prenatal, perinatal and postnatal factors in the explanation of socioeconomic inequalities in preschool asthma symptoms: the Generation R Study.
abstract: BACKGROUND
  The authors assessed whether socioeconomic inequalities in asthma symptoms were already present in preschool children and to what extent prenatal, perinatal and postnatal risk factors for asthma symptoms mediate the effect of socioeconomic status (SES).
  
  
  METHODS
  The study included 3136 Dutch children participating in the Generation R Study, a prospective cohort study. Adjusted ORs of asthma symptoms for low and middle SES (household income and maternal education) compared to high SES were calculated after adjustment for potential confounders and also adjusted for prenatal, perinatal and postnatal mediators at preschool age.
  
  
  RESULTS
  At age 1 year, low-SES children had a 40% lower risk of asthma symptoms compared to high-SES children (p<0.01). However, the risk of asthma symptoms in 3- and 4-year-old low-SES children was 1.5 times higher compared to their high-SES age mates (p<0.05). The positive associations at age 1 year were particularly modified by postnatal factors (up to 38%). In toddlers, prenatal factors explained up to 58% of the negative associations between SES and asthma symptoms.
  
  
  CONCLUSIONS
  SES indirectly affects asthma symptoms at preschool age. The inverse association between SES and asthma symptoms emerges at age 3 years. This is particularly due to a high level of adverse prenatal circumstances in low-SES toddlers. Future research should evaluate public health programs (during pregnancy) to reduce socioeconomic inequalities in childhood asthma.
authors.affiliation: The Generation R Study Group, Erasmus MC, Rotterdam, The Netherlands. e.hafkamp@erasmusmc.nl
authors.forename: Esther
authors.initials: E
authors.lastname: Hafkamp-de Groen
authors.forename: Lenie
authors.initials: L
authors.lastname: van Rossem
authors.forename: Johan C
authors.initials: JC
authors.lastname: de Jongste
authors.forename: Ashna D
authors.initials: AD
authors.lastname: Mohangoo
authors.forename: Henriëtte A
authors.initials: HA
authors.lastname: Moll
authors.forename: Vincent W V
authors.initials: VW
authors.lastname: Jaddoe
authors.forename: Albert
authors.initials: A
authors.lastname: Hofman
authors.forename: Johan P
authors.initials: JP
authors.lastname: Mackenbach
authors.forename: Hein
authors.initials: H
authors.lastname: Raat
mesh_terms: D000328:Adult; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology; D002675:Child, Preschool; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D016017:Odds Ratio; D018743:Perinatal Care; D011181:Postnatal Care; D011247:Pregnancy; D011295:Prenatal Care; D011297:Prenatal Exposure Delayed Effects; D015995:Prevalence; D011446:Prospective Studies; D012135:Respiratory Sounds / Q000209:etiology*; D012307:Risk Factors; D012931:Social Environment; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires