Weight and height growth velocities of Japanese boys and girls between age 7 and 14 years: a critical window for early adolescent overweight risk.

Childhood overweight is an important worldwide problem of public health concern, with metabolic, physical and psychosocial complications. More and more evidence is accumulating that children who gain weight rapidly earlier in life are at higher risk of becoming overweight later in adulthood life. Therefore, in a seven-year longitudinal study, we studied mid-childhood and early adolescence weight and height growth velocities among 5,024 Japanese 2(nd) grade primary school boys and girls along with its effect on the likelihood of being overweight adolescents by the age of 14 y. Our findings showed that weight growth velocity of both sexes was associated with being overweight at the end of longitudinal study. Boys' risk of accelerated weight growth velocity and becoming overweight adolescents was almost doubled during ages 7 approximately 11 y and become reduced afterward. Otherwise, odds ratios of girls' weight growth velocity peaks were found only at ages from 9 approximately 10 and 10 approximately 11 y. Thus, we suggest a critical window of mid-childhood period associated with adolescence risk of overweight, and we recommend that studying weight growth determinants during 7 approximately 11 y of boys and 9 approximately 11 y of girls may help in developing and applying proper programs for prevention and intervention of overweight problem.