Childhood thyrotoxicosis is an uncommon condition. To investigate the effect of thyrotoxicosis on the growth of children and to detect possible influence of the disease on their final height, 105 Chinese children (90 girls; 15 boys) with thyrotoxicosis were studied longitudinally from diagnosis. At presentation their mean age was 11. 57 years. Their height and weight measurements were converted to standard deviation scores (SDS) using normal height and weight-for-height reference standards for Chinese children established in Hong Kong. Their mean height SDS at diagnosis was +0. 73. Bone age assessment at diagnosis was done in 48 girls and 8 boys and their mean +/- S.D. bone development quotient was 1.16 +/- 0.11. A total of 53 girls have reached adult height and their mean height was 161.3 cm, corresponding to a SDS of +0.63. Their final heights significantly exceeded their target heights.
Conclusion: This study demonstrates that children with thyrotoxicosis were tall for age and their bone ages were advanced at presentation. They continued to be tall for age after starting treatment and they achieved final heights exceeding their target height.