Developmental pathways leading to obesity in childhood

Researchers have yet to provide a comprehensive explanation of the variability in the development of childhood obesity, owing in part to the dearth of longitudinal studies. Such an understanding would contribute to the improvement of approaches for the primary and secondary prevention of childhood obesity. This study identifies, in a representative sample of Canadian children, age-related patterns of overweight and obesity between toddlerhood and childhood.

The data are from cycles 2 through 5 (1996/1997 to 2002/2003) of the National Longitudinal Survey of Children and Youth. The sample comprised children aged 24 to 35 months at baseline, who were followed biennially over six years. Group-based mixture modelling analyses (using SAS PROC TRAJ) were conducted to identify the sex-specific developmental trajectories of body mass index (BMI).

Group-based modelling identified four BMI trajectories for the girls (stable normal BMI, early declining BMI, late declining BMI, and an accelerating rise to obesity) and three for the boys (stable normal BMI, transient high BMI, and a J-curve rise to obesity).

Identifying distinct, sex-specific BMI trajectories is valuable in understanding pathways through which a child may develop obesity. These findings have implications for further research and practice, in particular, that no single approach can be used to prevent or reduce levels of obesity.