Effect of neonatal intensive care unit hospitalization on incidence of attention deficit hyperactivity disorder in preschool children

Background: The exact etiology of attention deficit hyperactivity disorder (ADHD) has not yet been understood. Objectives: The aim of the current study was to investigate the effects of hospitalization at the neonatal intensive care unit (NICU) independent of other variables such as preterm birth and low birth weight on the incidence of ADHD. Materials and Method: This retrospective cohort study was done on an Exposed group of 100 preschool children with a history of NICU hospitalization at Amirkola children’s hospital, and an unexposed group of 100 children without such a history. Standard checklist of Diagnostic and statistic manual of mental disorders fourth edition (DSM-IV) was used to diagnose ADHD. Information on gender, current weight, birth weight, gestational age at birth, and type of parturition was also collected and obtained data were statistically analyzed by the SPSS software and unconditional logistic regression analysis. Results: Among the total number of 200 children, 20.5% of children were diagnosed to have ADHD. The incidence of the disorder was more in children with a history of hospitalization in neonatal intensive care unit than children without such a history (27% and 14%, respectively). Low birth weight and preterm birth were associated with the incidence of ADHD (P value = 0.001 and 0.005, respectively). Logistic regression showed that each day of NICU hospitalization was associated with 1.16 times greater risk of developing ADHD in the future when compared to children without a history of hospitalization (P value = 0.006). Conclusions: The risk of ADHD is independently increased with hospitalization at the NICU.