The effect of thyroxine treatment during the first two years of life in children with Down syndrome on development and growth at the age of 10.7 years

Abstract

s ingediend voor het Amsterdam Kindersymposium 2013 83 The effect of thyroxine treatment during the first two years of life in children with Down syndrome on development and growth at the age of 10.7 years JP Marchal (1), F Klouwer (1), E Witteveen (1), NA Ikelaar (1), K Verhorstert (1), BA Houtzager (2), MA Grootenhuis (3), ASP van Trotsenburg (1) (1) Department of Endocrinology, Emma Children’s Hospital, AMC (2) Deventer Hospital (3) Psychosocial Department, Emma Children’s Hospital, AMC INTRODUCTION A high percentage of young infants with Down syndrome (DS) have subclinical hypothyroidism, which may contribute to their suboptimal brain development and growth. Thyroxine (T4) treatment during their fi rst two years resulted in small improvements in motor development and growth, and a tendency towards improvement in mental development at the age of two years. The aim of our study was to examine whether this T4 treatment of infants with DS during their fi rst two years of life leads to better motor development, mental development or growth at the age of 10.7 years. METHODS We invited children who completed the previous trial (n=186) for a single follow-up visit at the age of 10.7 years. A blinded psychologist assessed motor and mental development using validated developmental tests. Growth and puberty were assessed by trained and blinded medical students, supervised by a pediatric endocrinologist. RESULTS We included 123 children (follow-up rate 68%), 52% of whom were in the T4-group and 52% were male. We found no diff erence in motor development (p=.90), motor coordination (p=.52) or mental development (p=.73). T4-treated children had a 0.6 cm larger head circumference (p=.04) and tended to be 2.1 cm taller than placebo-treated children (p=.06). Mean weight did not diff er between groups (p=.43). CONCLUSION Our results suggest that T4 treatment in children with DS during the fi rst two years of life does not lead to better motor or mental development at the age of 10.7 years. T4 treated children still tended to be slightly taller than placebo treated children.