Related Experiment Video
Updated: Mar 24, 2026
Assessment of Child Anthropometry in a Large Epidemiologic Study
Published on: February 2, 2017
Early-childhood BMI trajectories: evidence from a prospective, nationally representative British cohort study
1Senior Research Fellow, Primary Care and Population Sciences, Faculty of Medicine, University of Southampton, Aldermoor Health Centre, Aldermoor Close, Southampton, UK.
Insights
Childhood body mass index (BMI) trajectories are established early, with obesity linked to socio-economic factors and early life mechanisms like smoking during pregnancy. Early intervention is key to addressing childhood obesity and lifelong health outcomes.
Area of Science:
- Pediatric obesity research
- Developmental trajectories
- Socio-economic determinants of health
Background:
- Childhood overweight and obesity rates are rising, particularly in the UK, with 20% of children affected by age 5.
- Socio-economic inequalities significantly influence childhood and adult obesity.
- Early childhood is a critical period for establishing lifelong body mass index (BMI) trajectories.
Purpose of the Study:
- To identify distinct latent trajectories of body mass index (BMI) from ages 3 to 11 years in British children.
- To examine the socio-economic characteristics and underlying mechanisms during pregnancy and infancy associated with these BMI trajectories.
- To understand the early-life origins of childhood obesity and overweight.
Main Methods:
- Utilized a nationally representative prospective cohort study of 9,699 UK children born between 2000-2002.
- Collected interviewer-measured height and weight data at ages 3, 5, 7, and 11 years.
- Employed latent growth mixture models to calculate BMI trajectories and multinomial models to analyze socio-economic factors.
Main Results:
- Identified four BMI trajectories: normal weight (85%), overweight (14.4%), and obese (3.1%).
- The obese trajectory was distinct by age 3, while the overweight trajectory diverged around age 5.
- Significant socio-economic inequalities were observed, with early mechanisms like pregnancy smoking and not breastfeeding mediating disadvantage for the obese group.
Conclusions:
- Childhood BMI trajectories, particularly for obesity, are established very early in life.
- Strong socio-economic patterns suggest early life roots for growing health inequalities.
- Pregnancy and infancy mechanisms are crucial for the obese trajectory; further research on age 5 mechanisms is needed for the overweight trajectory.
Background And Objectives:
By age 5, 20% of British children are classed as overweight or obese, suggesting that early childhood is crucial for lifelong body mass index (BMI) trajectories. In this paper, we identify latent trajectories of early-childhood BMI from ages 3 to 11 years. Given the current context of growing socio-economic inequalities in childhood and adult overweight and obesity, we examine the socio-economic characteristics and mechanisms during pregnancy and infancy which underscore these trajectories.
Subject And Methods:
We use a nationally representative, prospective cohort study of 9699 children born in 2000-2002, living in the United Kingdom shortly after birth, with complete information on height and weight (measured by an interviewer) at ages 3, 5, 7 and 11. Trajectories of BMI are calculated using latent growth mixture models. Multinomial models characterize these trajectories by their socio-economic profiles and mechanisms during pregnancy and infancy.
Results:
Four trajectories were identified: two separate trajectories where BMI remains within a normal range (85% of the sample), an overweight trajectory (14.4%), and an obese trajectory (3.1%). No 'declining BMI' or late-onset groups were found. The obese group is already distinct from the other trajectories by age 3. The overweight group diverges from the normal groups around age 5. Strong socio-economic inequalities emerged; for the obese group, part of this disadvantage is mediated through early mechanisms such as pregnancy smoke and not initiating breastfeeding.
Conclusions:
This study provides strong evidence for the idea that childhood BMI trajectories develop early, especially for children who will follow an obese trajectory. Strong socio-economic patterns in these trajectories suggest that the observed trend in growing inequalities may be rooted in early life. Mediating mechanisms for the obese appear to be in the pregnancy and infant period, further research should explore mechanisms occurring around age 5 when the overweight trajectory diverges.
Related Concept Videos
01:52Regression Toward the Mean
01:26Longitudinal Studies
01:29Bias in Epidemiological Studies
01:30Socioemotional Development during Infancy
Primary Temperament Types
01:24Obesity
01:30Development of Human Microbiota