Multitrajectories of Macronutrient Intake and Their Determinants Among Young Australian Children: Results From the...

Changes in macronutrient intakes, their determinants, and associations with body weight outcomes in early childhood remain unclear.

To describe longitudinal changes (ie, trajectories) of macronutrient intakes, identify associated factors, and determine concurrent associations with trajectories of body mass index (BMI) z score in early childhood.

Secondary analysis of longitudinal data from the Melbourne Infant Feeding, Activity and Nutrition Trial Program, conducted from 2008 to 2013.

Australian children (N = 432) with 2 or more days of dietary intake data and BMI z score measurements were included.

Macronutrient intake (% energy intake) and BMI z scores were measured at ages 9 months, 18 months, 3.5 years, and 5 years.

Multitrajectory modeling identified groups of children following similar trajectories of protein, fat, and carbohydrate intakes. Multivariable logistic regression examined factors associated with macronutrient intake multitrajectories and associations with BMI z score trajectories.

Children followed 3 macronutrient, multitrajectory groups. Two groups exhibited consistently high carbohydrate or protein intakes and were referred to as "consistent high carbohydrate" and "consistent high protein," respectively. The third group showed variable macronutrient intake trajectories and was named "variable macronutrient." BMI z scores trajectories were categorized as low-BMIz, mid-BMIz, and high-BMIz. Higher maternal age was associated with a lower relative risk of children following a consistent high carbohydrate trajectory compared with a variable macronutrient trajectory (relative risk ratio [RRR] = 0.93; 95% CI, 0.87 to 0.99). Children of mothers born outside Australia had a lower relative risk of following a consistent high protein trajectory compared with a consistent high carbohydrate trajectory (RRR = 0.49; 95% CI, 0.27 to 0.92). Children who were breastfed for <6 months had a higher relative risk of following the consistent high protein trajectory compared with the consistent high carbohydrate group (RRR = 1.72; 95% CI, 1.03 to 2.86). No significant association was observed between trajectories of macronutrient intake and BMI z score trajectories.

Distinct macronutrient intake and BMI z score trajectories were observed in early childhood, and maternal age, country of birth, and breastfeeding duration were identified as determinants. No longitudinal associations were observed between macronutrient intakes and BMI z score trajectories.