Progression from childhood overweight to adolescent obesity in a large contemporary cohort

The overweight - as distinct from obese - child is a potential target for obesity prevention interventions, on the assumption that overweight often progresses to obesity. However, there is limited empirical evidence on the probability that overweight progresses to obesity in contemporary children. To quantify progression from overweight to obesity in a large contemporary cohort of children. Changes in weight status were studied longitudinally in 7-year-olds (n=5 175) participating in the Avon Longitudinal Study of Parents and Children (ALSPAC), over a 6-year period. Obesity was defined as BMI z-score ≥1.64 and overweight defined as BMI z-score ≥1.04 but <1.64. Adjusted odds ratio for progression to obesity at age 13 for overweight at age 7 was 18.1 (95% CI 12.8-25.6), and 34% of overweight children at age 7 became obese by age 13 years. The present study could inform judgements as to the value of monitoring changes in weight status in overweight children, and the extent to which the overweight state might be a useful target of future obesity prevention interventions.