Disease and child growth in industrialising Japan: assessing instantaneous changes in growth and changes in the growth pattern, 1911-39

This paper assesses how the disease environment in interwar Japan influenced children’s growth and health. The data is drawn from government records from 1929 to 1939 which report the average heights of boys and girls in school at each age (6-21) for each of Japan’s 47 prefectures. We test the influence of disease in two ways. First, we test the influence of the disease environment at birth, proxied by the infant mortality rate, on the cohort growth pattern of children using the SITAR model to parameterise the growth pattern. In addition, we use a bilateral-specific fixed effects model to understand how disease instantaneously influenced growth controlling for prefecture-birth cohort effects. Our results suggest that health conditions in early life did not have a strong influence on the growth pattern of children in Japan. However, we do find a significant and economically meaningful instantaneous effect of the infant mortality rate on child height at ages 6-11 for both boys and girls. This suggests that child morbidity was very important to the increase in stature during interwar Japan, but it also suggests that the emphasis placed on preventing child stunting in the first thousand days in the modern development literature may be misplaced. The secular increase in height in interwar Japan was more strongly influenced by cumulative responses to the health environment across child development rather than being simply the outcome of improving cohort health.