SUMMARY
The last few decades have seen a dramatic rise in the prevalence of obesity in children and adolescents. Being overweight or obese as a child poses considerable long-term risks, particularly for cardiovascular health. Historically, obesity was a disease of affluence. Today, both adults and children from lower socioeconomic backgrounds tend to be more overweight in high-income settings. In this essay, we present analysis of three research questions using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), a cohort of children born in the south west of the UK in 1991/2. Firstly, we review previously published results examining the age at which socioeconomic inequalities in adiposity emerge. Secondly, we discuss previously published evidence of socioeconomic inequalities in cardiovascular risk factors when the participants were age 10 years. And finally, we present new findings on the tracking of overweight/obesity across childhood and adolescence, and whether this differs across socioeconomic groups. Our findings show that socioeconomic differences in adiposity and cardiovascular risk factors emerge at a much earlier age than in older generations. If children are overweight/obese at age 7, there is a very low probability that they will return to a healthy weight by age 15 – although this is similar across socioeconomic groups. Together, these findings suggest an urgent need to prevent obesity at an early age, particularly amongst disadvantaged groups, in order to prevent wide socioeconomic differences in cardiovascular health in later life.