Chernobyl sick child syndrome persisting through life: testing the infancy inflammation hypothesis conditioned by socio-economic origin

Abstract: Previous research has shown that irradiation in-utero or during early childhood may cause longlasting damage. Studies on the Chernobyl accident have found that all birth groups which received high doses of radiation in early life may have severe persisting disadvantage in health. However, we do not know which of the groups irradiated in early life was the most vulnerable. We also do not know whether the accident directly left permanent scars on the health of those who were irradiated with low doses. Most importantly, we do not know whether radiation affected the health of these individuals indirectly, through the socio-economic conditions in early life. The recent wave of the Ukrainian Longitudinal Monitoring Survey of 2007 with individual-level data, and regional-level data on radiation doses from the National report of Ukraine on the Chernobyl accident of 2006 contain all the information needed to establish mechanisms between early-life irradiation and health status in adulthood. The study design distinguishes between different birth groups with varying exposure, such as exposed in-utero, exposed during infancy, exposed between the ages one and five, and conceived after the end of exposure period. The study covers two exposure periods, which lasted three months and eight months after the accident. Parental educational status is used as a socio-economic variable. Important controls include migration and place of birth. We find no direct effect from irradiation at low doses in early life on self-perceived health in young adulthood. However, we find that radiation strongly affected adult health through the socio-economic conditions in early life, especially for those who were exposed during infancy. This negative effect is found to be ameliorated to almost negligible levels by family resources. Individuals irradiated during infancy have the probability of 0.5 to have bad health in young adulthood if they had lived in poor families, and of 0.1 if they had lived in wealthy families. Much lower vulnerability and its amelioration is indicated for the group exposed while in-utero and between the ages one and five. However, only the effect for those irradiated during infancy is robust to different specifications. This effect is found also for those who received low doses of radiation.