Predictors of children's body mass index: a longitudinal study of diet and growth in children aged 2-8y

OBJECTIVE: To identify longitudinal variables related to children's body mass index (BMI) (kg/m(2)) at age 8 y. DESIGN: A longitudinal design, with nine interviews per child from ages 2 to 8 y. SUBJECTS: In all, 70 white children ( 37 males, 33 females) who were continuous participants since infancy in the longitudinal study. Families were primarily middle and upper socioeconomic status. MEASUREMENTS: At each interview, children's height and weight were measured, and mothers provided 3 days of the child's intake data ( a 24-h recall and 2 days of food records). ANALYSES: Analyses used were means +/- s.d., correlations, repeated measures analysis of variance, and forward stepwise regression. BMI at each interview was calculated and age of adiposity rebound was determined. RESULTS: Children's BMI at 8 y was negatively predicted by age of adiposity rebound and positively predicted by their BMI at 2 y. Additionally, each model included one longitudinal dietary variable; mean protein and fat intakes recorded between 2 and 8 y were positive predictors of BMI at 8 y; mean carbohydrate intake over the same time period was negatively related to BMI at 8y. R-2 values indicated that these three-variable models predicted 41 - 43% of the variability in BMI among children. BMI of 23% of the children exceeded the 85th CDC percentile. CONCLUSIONS: The results of this study show that factors in early life are associated with children's BMI at age 8 y.