Weight and height growth rate and the timing of adiposity rebound.

OBJECTIVE: Adiposity rebound occurs when the ratio of the velocities of log(weight) to log(height) changes from <2 to >2. This study examined the timing of adiposity rebound in the context of the velocities of weight and height in early childhood because it is not known whether faster weight gain or slower gain in stature is the more important determinant. RESEARCH METHODS AND PROCEDURES: This was a longitudinal study of 406 boys and 397 girls born in Dunedin, New Zealand, in 1972 and 1973. Each child's height and weight were measured at 3 years of age and at least twice more as part of their two yearly assessments until 11 years of age.
RESULTS: The mean age of adiposity rebound was 6.6+/-1.10 years (SD) for boys and 6.0+/-1.21 years for girls. After adjusting for sex, the correlations between the timing of rebound and z-scores for BMI, weight, and height at rebound were -0.35, -0.30, and -0.14, respectively. Correlations between the timing of rebound and estimated values of weight and height velocities at 3 years were -0.48 and -0.00. The correlations with BMI and waist girth at 26 years were -0.39 and -0.35. DISCUSSION: Children with an earlier adiposity rebound were heavier and had above average BMIs. Early rebound is the result of higher rates of weight gain, measured in percentage terms, rather than slower than average accrual of stature. This suggests that restraining weight gain could delay adiposity rebound and prevent obesity in early adulthood.