Stability and change in dietary scores and patterns across six waves of the Longitudinal Study of Australian Children

Child development
Friday 27 July, 1115 – 1135


Constantine Gasser
Australian Institute of Family Studies

This study aimed to derive and compare longitudinal trajectories of dietary scores and patterns from 2–3 to 10–11 years and from 4–5 to 14–15 years of age. In Waves 2 to 6 of the B Cohort and 1 to 6 of the K Cohort of the Longitudinal Study of Australian Children, parents or children reported biennially on the study child’s consumption of 12–16 healthy and less healthy food or drink items for the previous 24 hours. For each wave, we derived a dietary score from 0 to 14, based on the 2013 Australian Dietary Guidelines (higher scores indicating healthier diet).

We then used factor analyses to empirically derive dietary patterns for separate waves. Using group-based trajectory modelling, we generated trajectories of dietary scores and empirical patterns in 4,504 B and 4,640 K Cohort children.

Four similar trajectories of dietary scores emerged for the B and K Cohorts, containing comparable proportions of children in each cohort: “never healthy” (8.8% and 11.9% respectively), “moderately healthy” (24.0% and 20.7%), “becoming less healthy” (16.6% and 27.3%) and “always healthy” (50.7% and 40.2%). Deriving trajectories based on dietary patterns, rather than dietary scores, produced similar findings.

For “becoming less healthy” trajectories, dietary quality appeared to worsen from 7 years of age in both cohorts. In conclusion, a brief dietary measure administered repeatedly across childhood generated robust, nuanced dietary trajectories that were replicable across two cohorts and two methodologies. These trajectories appear ideal for future research into dietary determinants and health outcomes.