The Relationship Between Physical Development and Economic Growth in Japan: From the Perspective of Regional Differences in Biological Parameters

Following the Second World War, there was a rapid increase in body size in Japan as a result of qualitative changes in the human environment from marked economic growth and the stable supply of nutrition. A phenomenon that facilitated this physical growth may be seen in the larger body sizes and earlier maturation combined with the secular trends in GDP resulting from high economic growth. However, this high economic growth did not occur uniformly nationwide. Similarly in physical growth, the trend for earlier maturation was not seen uniformly nationwide. This study applied the wavelet interpolation method to identify the age at maximum peak velocity (MPV) in pubertal growth (a biological parameter) from the growth velocity curves for height described for the 47 prefectures of Japan from 1955 to 2015. A secular trend model of this biological parameter was then constructed. This parameter as seen particularly in urban and rural areas was then applied to the secular trend model and, based on a composition that eliminates regional differences, the possibilities as a barometer of economic growth based on the biological parameter of early maturation were then explored. The results showed a trend for earlier maturation in all prefectures for both boys and girls. The multi-year span evaluation chart in this study showed a trend for earlier maturation from 1955 to 1970 in Tokyo and other large cities, after which there was a transition to average maturation. In Aomori, Oita and other rural areas, there was a trend for late maturation from 1955 to 1970, followed by a transition to earlier maturation. From these trends, there may be said to be a close relationship between physical growth and socioeconomic status. However, since the late 1990s the difference in maturation rate in urban and rural regions has disappeared. This may be from the effect of high economic growth coming to an end.