Adolescent height growth of girls in Tokyo

Abstract

This is the first study of longitudinal growth of Japanese subjects carried out by applying the Preece-Baines model 1 (PB1) function. Ninety-three sets of longitudinally-followed height data from a series of girls in Tokyo were analyzed by fitting the PB1 model. We first compared the PB1 results with those previously obtained from the cubic spline function. We then examined correlation among biological variables within this Japanese group, and then compared the PB1-derived biological variables among populations. The biological variables, except for age at peak velocity and peak height velocity, were confirmed to be distributed normally. In comparison with previous results obtained by the cubic spline function for the same subjects, the PB1-derived velocity curve was found to be more emphasized. Ages at take-off and at peak were 0.2 years younger and older, respectively, and height was 1 cm less at take-off and 1.3 cm greater at peak. Within the Tokyo girls, many variables were significantly correlated. However, the number of variable pairs that showed a significant correlation was considerably fewer in the among-population comparisons than in the within-group analysis of the Tokyo girls. Comparisons of the Tokyo series with those from seven other populations revealed that groups whose adult height was greater already had greater heights at take-off and at peak.