ABSTRACT
Objective: To evaluate the success rate of the Nationalnewborn screening program in maintenance of intelligent quotient(IQ) of children with congenital hypothyroidism in Iran.Design: Retrospective cohort study.Methods: The IQ scores, in three subsets of verbal, non verbal(Performance) and full scale IQ, of 240 children diagnosed withTransient congenital hypothyroidism (TCH) and Permanentcongenital hypothyroidism (PCH), from 5 provinces in 5 differentgeographical areas of Iran, were measured at the age of 6 yearsusing revised Wechsler pre school and primary scale ofintelligence and compared with 240 healthy children. We usedindependent sample t test and two-way ANOVA for data analysis. Results: Mean of verbal, performance, and full scale IQ scoreswere lower in the CH cases (permanent and transient) than thecontrol group. Most of the IQ differences in two studied groupsrelated to the PCH cases (P=0.005). Mean difference of IQsbetween children in the two groups in Yazd province (center ofIran) was higher than other provinces, and they also hadsignificantly lower IQ than their control (healthy) children(P=0.001). No treated child had IQ<70.Conclusion: Although mean IQs of CH children was lower thantheir controls, IQ of all treated CH cases were close to the healthychildren