(P17-072-25) Longitudinal Association Between Trajectories of Macronutrient Intake and Body Mass Index Among Young Australian Children

Objectives: This study examined changes in energy and macronutrient intakes (i.e. trajectories), associated factors, and concurrent associations with trajectories of body mass index (BMI) z-scores from 9 months to 5 years of age.

Methods: Data of 432 children from the Melbourne InFANT Program were used. Macronutrient intake (% energy intake) and BMI z-scores were assessed at ages 9 months, 18 months, 3.5 years, and 5 years. Multi-trajectory modelling identified groups of children following distinct intake trajectories of protein, fat, carbohydrate (CHO). Group-based trajectory modelling identified trajectories of total energy intake and BMI z-score. Multivariable logistic regression assessed factors associated with macronutrient intake multi-trajectories and concurrent associations with BMI z-score trajectories.

Results: Two energy intake trajectories were identified: “Low” (65.7%) and “High” (34.3%). We found three distinct macronutrient multi-trajectory groups: “Moderate Protein, Low CHO, High Fat” (25.0%); “Moderate Protein, High CHO, Low Fat” (50.5%); or “High Protein, Low CHO, Moderate Fat” (24.5%), and referred as “High Fat”, “High CHO”, or “High Protein”, respectively by the macronutrient contributing the highest proportion of energy. Three BMI z-scores trajectories of “Low” (22.7%), “Mid” (58.7%), and “High” (18.6%) were identified. Higher maternal age (years) was associated with lower odds of children following the “High CHO” trajectory compared to the “High Fat” trajectory (OR 0.93; 95% CI: 0.87–0.99). Children of mothers born outside Australia had higher odds of following the “High CHO” trajectory compared to the “High Protein” trajectory (OR 2.04; 95% CI: 1.01–4.13). No evidence of association was found between trajectories of energy or macronutrient and BMI z-score.

Conclusions: Distinct trajectories of energy, macronutrient intakes, and BMI z-score were observed in early childhood and maternal age and country of birth were identified as determinants. No longitudinal associations were observed between energy or macronutrient intakes and body weight outcomes in early childhood.

Funding Sources: The Melbourne INFANT Program, and the follow-ups were funded by the National Health and Medical Research Council Project Grant. M.Z. is supported by the Australian Research Council Discovery Early Career Researcher Award Fellowship.