BMI at 13 years as a function of BMI at 7 years by sex and birth cohort^a.

Abbreviations: CI, confidence interval. aChildren with a BMI at age 7 years <10.5 (n = 38) were not included. bThe estimate for the increase in BMI units at 13 years (kg/m2) per BMI unit increase at 7 years (kg/m2) is derived from a model including the main effect of BMI at 7 years, sex, cohort, age at 7 years in months and two- and three-way interactions between sex, birth cohort and BMI at 7 years.