Article Text

Download PDFPDF

P90 Socio-economic variation in child bmi trajectory from infancy to adolescence in three contemporary european child cohorts
  1. C McCrory1,
  2. S Leahy1,
  3. A.I. Ribeiro2,
  4. S Fraga2,
  5. H Barros2,
  6. R Layte3
  1. 1The Irish Longitudinal Study on Ageing (TILDA), Trinity College Dublin, Dublin, Ireland
  2. 2EPIUNIT, Institute of Public Health University of Porto, Porto, Portugal
  3. 3Department of Sociology, Trinity College Dublin, Dublin, Ireland


Background Rates of overweight and obesity have been shown to vary across socio-economic groups (SEG) from at least the age of three years but little is known about whether SEG differentials vary after adipose rebound and into adolescence and whether these trajectories differ by national context. This study examines socio-economic differentials in children’s body mass trajectories in infancy and extending across childhood into early adolescence in three contemporary child cohort studies.

Methods Data on body mass index (BMI) measured on at least three occasions between birth and adolescence was obtained from four prospective cohort studies – Generation 21 (G21–Portugal), Growing Up in Ireland (GUI–Ireland) (infant and child cohorts), and the Millennium Cohort Study (MCS–UK) – involving a total sample of 44 136 children. SEG differentials in children’s BMI trajectories was modelled by maternal educational level (primary, secondary, tertiary) using hierarchical models with fixed and random components for each cohort study.

Results Child BMI growth trajectory was greater for children of lower educated mothers but only from three years of age. In G21, the educational differential emerged by 4 years of age and increased from 0.25boys [CI95=0.14, 0.38] and 0.44girls [CI95=0.30, 0.58] to 0.45boys [CI95=0.25, 0.64] and 0.70girls [CI95=0.48, 0.92] by 7 years of age. In GUI, the mean difference in BMI between polarised educational groups increased from 0.21boys [CI95=0.08, 0.35] and 0.35girls at 3 years of age [CI95=0.21, 0.49] to 0.92boys [CI95=0.63, 1.21] and 1.40girls [CI95=1.09, 1.71] by 13 years of age. In MCS, the educational differential was first observed at 5 years of age and increased from 0.14boys [CI95=0.06, 0.23] and 0.19girls [CI95=0.10, 0.28] to 0.66boys [CI95=0.49, 0.83] and 0.61girls [CI95=0.42, 0.79] by 11 years of age.

Conclusion Socio-economic factors are strongly implicated in the aetiology of childhood obesity. This study shows that the socio-economic differentials emerge in early childhood and widen over time providing important policy evidence about the timing of potential policy interventions designed to eliminate the adverse life course health effects associated with early emerging adiposity.

  • health inequalities
  • body mass index
  • growth curves

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.