title: Do early-life exposures explain why more advantaged children get eczema? Findings from the U.K. Millennium Cohort Study.
abstract: BACKGROUND
  Atopic dermatitis (eczema) in childhood is socially patterned, with higher incidence in more advantaged populations. However, it is unclear what factors explain the social differences.
  
  
  OBJECTIVE
  To identify early-life risk factors for eczema, and to explore how early-life risk factors explain any differences in eczema.
  
  
  METHODS
  We estimated odds ratios (ORs) for ever having had eczema by age 5 years in 14 499 children from the U.K. Millennium Cohort Study (MCS), with a focus on maternal, antenatal and early-life risk factors and socioeconomic circumstances (SECs). Risk factors were explored to assess whether they attenuated associations between SECs and eczema.
  
  
  RESULTS
  Overall 35·1% of children had ever had eczema by age 5 years. Children of mothers with degree-level qualifications vs. no educational qualifications were more likely to have eczema (OR 1·52, 95% confidence interval 1·31-1·76), and there was a gradient across the socioeconomic spectrum. Maternal atopy, breastfeeding (1-6 weeks and ≥ 6 months), introduction of solids under 4 months or cow's milk under 9 months, antibiotic exposure in the first year of life and grime exposure were associated with an increased odds of having eczema. Female sex, Pakistani and Bangladeshi ethnicity, smoking during pregnancy, exposure to environmental tobacco smoke and having more siblings were associated with reduced odds for eczema. Controlling for maternal, antenatal and early-life characteristics (particularly maternal smoking during pregnancy, breastfeeding and number of siblings) reduced the OR for eczema to 1·26 (95% confidence interval 1·03-1·50) in the group with the highest educational qualifications compared with the least.
  
  
  CONCLUSIONS
  In a representative U.K. child cohort, eczema was more common in more advantaged children. This was explained partially by early-life factors including not smoking during pregnancy, breastfeeding and having fewer siblings.
authors.affiliation: Department of Public Health and Policy, Whelan Building, University of Liverpool, Liverpool, L69 3GB, U.K.|UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, U.K.
authors.forename: D C
authors.initials: DC
authors.lastname: Taylor-Robinson
authors.affiliation: Centre of Evidence Based Dermatology, University of Nottingham, Nottingham, U.K.
authors.forename: H
authors.initials: H
authors.lastname: Williams
authors.affiliation: UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, U.K.
authors.forename: A
authors.initials: A
authors.lastname: Pearce
authors.affiliation: UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, U.K.
authors.forename: C
authors.initials: C
authors.lastname: Law
authors.affiliation: UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, U.K.
authors.forename: S
authors.initials: S
authors.lastname: Hope
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D002675:Child, Preschool; D004485:Eczema / Q000453:epidemiology*; D004522:Educational Status; D004781:Environmental Exposure / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008423:Maternal Age; D009035:Mothers / Q000706:statistics & numerical data; D015995:Prevalence; D012307:Risk Factors; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult