Objective.

To determine the effects of timing of onset of overweight (OW) on childhood anthropometric adiposity levels using long-term serial data from the Fels Longitudinal Study.

Classification.

OW was defined as body mass index (BMI; kg/m2) >25, and the age at first measurement of BMI >25 was the age of onset of OW. Early onset of OW (early-OW) and late onset of OW (late-OW) were defined as having onset of OW before and after 25 years of age, respectively, whereas never OW (never-OW) was defined as never having a BMI >25.

Subjects.

Subjects consisted of 67 males and 47 females in early-OW groups, 62 males and 48 females in late-OW groups, and 80 males and 114 females in never-OW groups.

Results.

Levels of weight and BMI in early-OW males and females were significantly greater than those in never-OW and late-OW males and females beginning at the time of adiposity rebound, which generally occurs between 4 and 8 years of age. Median BMI and weight patterns between never-OW and late-OW males were similar throughout childhood. However, significant differences in median levels of BMI for never-OW and late-OW females began at 11 years of age, although onset of OW was not until >25 years of age in the latter group.

Conclusions.

For both males and females, adiposity rebound is likely an effective time in a child's development to detect and initiate prevention for childhood and early adulthood onset of OW. Although later-onset OW needs additional study, puberty seems to be a critical phase in the development of later adult onset of OW in females.