Cognitive Outcomes in Congenital Hypothyroidism: Impact of Socioeconomic Status - A Case-Control Study

Chile is one of the few high-income countries in Latin America, being a pioneer in implementing a national newborn screening (NBS) program in 1992. Currently, it covers 98% of the population, but no long-term outcomes have been described so far. The aim of this study was to report the neurocognitive outcomes of children with congenital hypothyroidism (CH) diagnosed by the NBS program in Chile between 2005 and 2012 and to identify variables associated with the outcomes.

We performed a case-control study in children with CH born in the two largest regions of the country. The Leiter-R and TEVI-R tests were administered at home to 69 children with CH and 68 matched control subjects. Other variables affecting cognition were obtained. Multivariate logistic regression analyses were performed for Leiter-R and TEVI-R tests, using a model for cases alone and another model for cases and controls.

No differences in Leiter-R and TEVI-R results were observed between children with CH and the control group. Children who performed better, regardless of whether they had CH, had a higher family income and more assets.

These results suggest that the Chilean NBS program strategy results in children with normal language, attention, and memory development. Socioeconomic disadvantage represents a significant detriment in cognitive function.