A longitudinal study of obesity in Japan: relationship of body habitus between at birth and at age 17.

To clarify the relationship between body habitus from birth to adolescence, changes in weight and height of 309 boys and 335 girls were observed at birth, 3, 6, 11, 14 and 17 years old. Body mass index (BMI = W/H2) was calculated to estimate their habitus at birth, 3 and 17 years, and Rohrer index (W/H3) was used for 6, 11 and 14 years habitus. We define the children in the top decile as obese and those in the bottom decile as lean. Among girls obesity at 17 years old is already related to habitus at birth, while among boys it is related to habitus at 3 years old. Based on these results, we tentatively recommend that prevention of obesity should start as early as possible, at the least from 3 years old.