This article uses the health shock on Japanese civilians of the Second World War to understand the effects of health shocks at different developmental stages on children's long-run growth pattern and to test whether recovery is possible after an early-life health shock. We construct a prefecture-level dataset of mean heights of boys and girls aged 6–19 from 1929 to 2015. Linking the heights recorded at different ages for the same birth cohort, we measure a counterfactual causal effect of the health shocks during the Second World War on the cohort growth pattern of children. We find that the war effect was greatest for cohorts exposed to the war in late childhood and adolescence: these cohorts were 1.7–3.0 cm shorter at adulthood and had delayed pubertal growth and slower maturation than they would have had if the war had never occurred. However, there were no persistent health penalties for children exposed to the war in early life, suggesting that catch-up growth was possible as health conditions improved after the war. These findings challenge the thousand-days consensus that children cannot recover from nutritional shocks in early life and indicate that adolescence is a sensitive period for health shocks.

中文翻译：

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健康冲击、恢复和最初的一千天：第二次世界大战对日本儿童身高增长的影响

本文利用二战对日本平民的健康冲击来了解不同发育阶段的健康冲击对儿童长期生长模式的影响，并测试早期健康冲击后是否有可能恢复。我们构建了 1929 年至 2015 年 6-19 岁男孩和女孩平均身高的地级市级数据集。将同一出生队列在不同年龄记录的身高联系起来，我们测量了第二次世界大战期间健康冲击的反事实因果效应对儿童群体成长模式的战争。我们发现，在童年晚期和青春期暴露于战争的群体中，战争效应最大：这些群体在成年期矮了 1.7-3.0 厘米，并且与从未发生过战争时相比，青春期生长延迟和成熟更慢。然而，对于早年暴露于战争的儿童并没有持续的健康处罚，这表明随着战后健康状况的改善，追赶增长是可能的。这些发现挑战了儿童无法从早年营养冲击中恢复的千日共识，并表明青春期是健康冲击的敏感时期。