Tracking Preschoolers' Lifestyle Behaviors and Testing Maternal Sociodemographics and BMI in Predicting Child Obesity Risk.

Background: Longitudinal data investigating tracking of children's lifestyle behaviors and predictors of childhood obesity are limited.

Objectives: We examined changes in children's lifestyle behaviors (dietary, physical activity, and screen time) from ages 2-5 y to determine if maternal sociodemographic factors and BMI predict child obesity at 3.5 y and 5 y.

Methods: Data were obtained from 667 first-time mothers who were recruited into the Healthy Beginnings Trial at 24-34 weeks of gestation in Sydney, Australia. Child lifestyle behaviors were assessed using face-to-face questionnaire interviews with mothers. To measure child and maternal anthropometry, BMI (in kg/m2) was calculated using measured height and weight. Children were categorized as overweight or obese based on the International Obesity Task Force criteria. We used 1-factor repeated-measures ANOVA to track preschoolers' lifestyle behaviors and multiple logistic regression to determine obesity predictors.

Results: In children aged 2-5 y, consumption of vegetables (ηp2 = 0.06; P < 0.005) and milk (ηp2 = 0.02; P < 0.001) decreased, whereas physical activity (ηp2 = 0.07; P < 0.001) increased. Discretionary foods (sweet snacks, fast foods, salty snacks, processed meats, confectionary) (ηp2 = 0.03-0.25; P ≤ 0.01) and screen time (ηp2 = 0.39; P < 0.001) increased. Maternal BMI (in kg/m2) (Exp β: 1.06; 95% CI:1.01, 1.12 ; P=0.02), marital status (married/de facto compared with single) (Exp β: 0.06; 95% CI:0.01, 0.26; P < 0.001), and child BMI at 2 y (Exp β: 1.82; 95% CI: 1.46, 2.27; P < 0.001) predicted overweight/obesity at 3.5 y. Child BMI at 3.5 y (Exp β: 3.51; 95% CI: 2.50, 4.93; P < 0.001) predicted obesity at 5 y.

Conclusions: Poor dietary and lifestyle behaviours track in early childhood, with maternal single-parent status and high maternal and child BMI at 2 y predicting earlier obesity onset.