Associations between low birth weight, childhood adversity, and natural disaster with delay discounting among children

According to the Developmental Origins of Health and Disease (DOHaD) hypothesis, low-birthweight (LBW) infants are programmed to seek additional resources as compensation for early deprivation. However, no study has yet explored this in the context of delay discounting (DD), which refers to the tendency to prefer smaller, immediate rewards over larger, delayed ones. Both prenatal factors, such as LBW, and postnatal factors, including adverse childhood experiences (ACEs) and exposure to natural disasters, may influence DD. To investigate whether LBW children seek larger future rewards, we analyzed LBW's effect on DD, accounting for ACEs and natural disaster exposure. This prospective cohort study involved 167 children from areas affected by the Great East Japan Earthquake (GEJE), with a mean age of 8.3 years at the time of the DD experiment. LBW was assessed in the 2012 baseline questionnaire using the Mother-Child Handbook, along with ACEs prior to the GEJE and traumatic earthquake experiences. In 2014, DD was assessed through a token-based experiment where children allocated tokens for either immediate rewards (one candy per token for "now") or delayed rewards (two candies per token for "one month later"). Our results showed that children with LBW and three or more ACEs exhibited lower DD, while traumatic earthquake experiences were not associated with DD. These findings suggest that children with LBW and multiple ACEs may develop adaptive strategies to seek more resources, indicating a responsive reward system to childhood adversity, even after exposure to a severe natural disaster.