A comparison of target height estimated and final height attained between Swedish and Hong Kong Chinese children

Abstract

Target height, the genetic potential in stature, is commonly estimated by the corrected midparental height (CMH) method. A new model for estimating target height has recently been introduced based on a large, Swedish, population-based study. The aim of this study was to compare the validity of the two methods for estimating target height in Hong Kong Chinese children. The Hong Kong Chinese were more than 10 cm shorter than the Swedes in stature. The secular increase in height over the two generations, however, was 4.2-4.8 cm for the Hong Kong Chinese, much larger than that of the Swedes (0.7-1.0 cm). The two populations are thus at different stages in the secular trend. The new model derived from Swedish population for estimating target height was shown to be applicable to Hong Kong Chinese children; the mean of residual final height values was close to zero (-0.15 cm, p=0.74). However, the mean of residual final height was significantly above the expected value of zero (4.5 cm, p < 0.0001) when the CMH method was applied to the data, which implies an underestimation bias of 4.5 cm. Consequently, if the CMH method is used to estimate target height and evaluate growth hormone treatment responses in short children, it may inflate the treatment response by 4.5 cm. In conclusion, the recently proposed model for target height estimation offers a better alternative for estimating target height in Hong Kong Chinese children and for assessing growth-promoting treatments.