Invisible threat, tangible harm: Radiation anxiety and birth outcomes after Fukushima
Journal of Health Economics · 2026 · Rong Fu、Yunkyu Sohn、Yichen Shen、Haruko Noguchi
中文摘要
识别产前心理压力对出生结局的因果效应颇具挑战，因为应激事件通常将心理压力与物质生活冲击捆绑在一起。2011年福岛核事故为克服这一挑战提供了独特的情境：物理辐射暴露在地理上范围有限且被充分记录，而对辐射的恐惧却蔓延至全国。我们利用这一地理上的分离来考察母亲焦虑如何独立影响胎儿发育。我们使用与人口普查数据相链接的日本全民出生记录，并结合一种基于谷歌趋势的新颖辐射特异性焦虑衡量指标，采用三种互补的识别策略：在子宫内暴露与未暴露队列的人群层面比较、控制不随时间变化的家庭特征的家庭内同胞分析，以及利用焦虑强度地理差异的剂量—反应估计。在孕期经历该事故使早产增加17%，并使出生体重降低22—26克。出生结局与焦虑强度呈现清晰的剂量—反应关系，其中辐射特异性焦虑可解释总体早产效应的72—79%以及总体出生体重效应的28—37%。效应集中于社会经济弱势母亲以及孕早期暴露，且对原本就脆弱、处于极低和超低出生体重类别的婴儿影响最为严重。我们的发现表明，看不见的威胁通过心理压力路径产生可测量的代际健康影响，这对从大流行病到气候变化等当代危机中的灾害准备和风险沟通具有启示意义。
Abstract
Identifying causal effects of prenatal psychological stress on birth outcomes is challenging because stressful events typically bundle psychological stress with material disruptions. The 2011 Fukushima nuclear accident provides a unique setting to overcome this challenge: while physical radiation exposure was geographically limited and well-documented, fear of radiation spread nationwide. We exploit this geographic separation to examine how maternal anxiety independently affects fetal development. Using universal Japanese birth records linked to census data, combined with a novel Google Trends-based measure of radiation-specific anxiety, we employ three complementary identification strategies: population-level comparisons of in-utero exposed versus unexposed cohorts, within-family sibling analysis controlling for time-invariant family characteristics, and dose-response estimation exploiting geographic variation in anxiety intensity. Experiencing the accident during pregnancy increased preterm births by 17% and reduced birth weights by 22-26 grams. Birth outcomes exhibit a clear dose-response relationship with anxiety intensity, with radiation-specific anxiety accounting for 72-79% of the overall preterm birth effects and 28-37% of the overall birth weight effects. Effects are concentrated among socioeconomically disadvantaged mothers and during first-trimester exposure, with the most severe impacts on already-vulnerable infants in the very low and extremely low birth weight categories. Our findings indicate that invisible threats generate measurable intergenerational health impacts through psychological stress pathways, with implications for disaster preparedness and risk communication during contemporary crises from pandemics to climate change.