title: Fit to WHO weight standard of European infants over time.
abstract: OBJECTIVE
  The 2006 WHO growth charts were created to provide an international standard for optimal growth, based on healthy, breastfed populations, but it has been suggested that Northern European children fit them poorly. This study uses infant weight data spanning 50 years to determine how well-nourished preschool children from different eras fit the WHO standard, and discuss the implications of deviations.
  
  
  METHODS
  Four longitudinal datasets from the UK and one from Finland were used comprising over 8000 children born between 1959 and 2003. Weights from birth to 2 years were converted to age-sex-adjusted Z scores using the WHO standard and summarised using Generalized Additive Models for Location, Scale and Shape.
  
  
  RESULTS
  Weights showed a variable fit to the WHO standard. Mean weights for all cohorts were above the WHO median at birth, but dipped by up to 0.5 SD to a nadir at 8 weeks before rising again. Birth weights increased in successive cohorts and the initial dip became slightly shallower. By age 1 year, cohorts were up to 0.75 SD above the WHO median, but there was no consistent pattern by era.
  
  
  CONCLUSIONS
  The WHO standard shows an acceptable, but variable fit for Northern European infants. While birth weights increased over time, there was, unexpectedly, no consistent variation by cohort beyond this initial period. Discrepancies in weight from the standard may reflect differences in measurement protocol and trends in infant feeding practice.
authors.affiliation: School of Mathematics and Statistics, University of Glasgow, Glasgow, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Levin
authors.affiliation: School of Mathematics and Statistics, University of Glasgow, Glasgow, UK.
authors.forename: Louise
authors.initials: L
authors.lastname: Marryat
authors.affiliation: Population, Policy and Practice Programme, UCL Institute of Child Health, London, UK.
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Cole
authors.affiliation: School of Mathematics and Statistics, University of Glasgow, Glasgow, UK.
authors.forename: John
authors.initials: J
authors.lastname: McColl
authors.affiliation: Department for International Health, University of Tampere School of Medicine, Tampere, Finland Department of Paediatrics, Tampere University Hospital, Tampere, Finland.
authors.forename: Ulla
authors.initials: U
authors.lastname: Harjunmaa
authors.affiliation: Department for International Health, University of Tampere School of Medicine, Tampere, Finland Department of Paediatrics, Tampere University Hospital, Tampere, Finland.
authors.forename: Per
authors.initials: P
authors.lastname: Ashorn
authors.affiliation: Department of Child Health, University of Glasgow, Queen Elizabeth University Hospital, Glasgow, UK.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Wright
mesh_terms: D001835:Body Weight / Q000208:ethnology*; D002675:Child, Preschool; D005006:Ethnicity; D005260:Female; D005387:Finland; D057238:Growth Charts; D006801:Humans; D007223:Infant; D008297:Male; D006113:United Kingdom; D015430:Weight Gain / Q000208:ethnology*; D044465:White People; D014944:World Health Organization
keywords: Epidemiology; General Paediatrics; Growth; Nutrition; Obesity