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Research

Development of adiposity in adolescence: five year longitudinal study of an ethnically and socioeconomically diverse sample of young people in Britain

BMJ 2006; 332 doi: https://doi.org/10.1136/bmj.38807.594792.AE (Published 11 May 2006) Cite this as: BMJ 2006;332:1130
  1. Jane Wardle, professor of clinical psychology (j.wardle{at}ucl.ac.uk)1,
  2. Naomi Henning Brodersen, research fellow1,
  3. Tim J Cole, professor of medical statistics2,
  4. Martin J Jarvis, emeritus professor of health psychology1,
  5. David R Boniface, statistician1
  1. 1 Cancer Research UK Health Behaviour Unit, Department of Epidemiology and Public Health, University College London, London WC1E 6BT
  2. 2 Department of Epidemiology and Public Health, Institute of Child Health, London WC1N 1EH
  1. Correspondence to: J Wardle
  • Accepted 7 March 2006

Abstract

Objective To examine the developmental trajectory of obesity in adolescence in relation to sex, ethnicity, and socioeconomic status.

Design Five year longitudinal cohort study of a socioeconomically and ethnically diverse sample of school students aged 11-12 years at baseline.

Setting 36 London schools recruited to the study in 1999 by a stratified random sampling procedure.

Participants 5863 students participated in one or more years.

Main outcome measures Weight, height, and waist circumference measured annually by trained researchers; overweight and obesity defined according to International Obesity Task Force criteria; adiposity and central adiposity indexed by body mass index (BMI) and waist standard deviation scores relative to 1990 British reference values.

Results In school year 7 (age 11-12), the prevalence of overweight and obesity combined was almost 25%, with higher rates in girls (29%) and students from lower socioeconomic backgrounds (31%) and the highest rates in black girls (38%). Prevalence of obesity increased over the five years of the study at the expense of overweight, but no reduction occurred in the proportion of students with BMIs in the healthy range. Waist circumferences were high compared with 1990 norms at age 11 (by 0.79 SD in boys and by 1.15 SD in girls) and increased further over time. Both BMI and waist circumference tracked strongly over the five years.

Conclusions Prevalence of overweight and obesity was high in London school students, with significant socioeconomic and ethnic inequalities. Little evidence was found of new cases of overweight or obesity emerging over adolescence, but few obese or overweight adolescents reduced to a healthy weight. The results indicate that persistent obesity is established before age 11 and highlight the need to target efforts to prevent obesity in the early years.

Footnotes

  • Embedded Image An extra table is on bmj.com

    We gratefully acknowledge the participation of the 36 schools and 5863 students and the work of all those involved in collecting the data.

  • Contributors All authors participated in the conception, analysis, and interpretation of the study. JW and NHB wrote the manuscript, and JW, DRB, TJC, and MJJ were involved in revising the original manuscript. JW is the guarantor.

  • Funding This research was supported by Cancer Research UK, which had no involvement in the study itself or its interpretation.

  • Competing interests None declared.

  • Ethical approval University College London/University College London Hospital medical ethics committee.

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