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

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 8 y. 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.