Reference charts of body proportion for Japanese girls and boys

Data from previous studies provided the mean values of body proportions for each age group of healthy Japanese children, but not the standard curves describing the distribution.

The aim of the study was to construct a chart of body proportion of girls and boys in Japan.

About 4% of the nationwide student population in Japan, more than 20,000 children per group of both boys and girls of all ages, was included randomly. The upper/lower ratio (ULR) was calculated from correlation tables containing stature and sitting height data reported in the Statistical Report on School Health and Hygiene. The subischial leg length was calculated by subtracting sitting height from stature.

The present study showed that Japanese boys (13.5-17.5 years old) were taller and had relatively longer legs than Japanese girls in the same age group, and that the median ULRs of Japanese girls and boys (5.5-17.5 years old) were larger than the average of Caucasian girls and boys reported previously. In boys, the percentile values reached the lowest at 13.5 years, then increased slightly. On the other hand, in girls, the percentile values remained constant after 11.5 years, which is different in boys in the present study and in other Caucasian populations obtained from several studies.

The new chart provides useful information in the assessment of the body proportions of Japanese children.