Long-term effects of L-thyroxine therapy for congenital hypothyroidism☆,☆☆,★,★★
Section snippets
Sample
Subjects were 65 female and 29 male children born between 1976 and 1985 with CH detected by one of two screening programs.14, 15 These children represented more than 90% of a larger cohort that was participating in a long-term prospective study to evaluate outcome after screening, most since the age of 1 year.16 Nonparticipants included 5 children who moved, 2 with transient hypothyroidism, and 4 dropouts; one child with an IQ less than 60, unrelated to his thyroid hormone deficiency, was
RESULTS
The results were initially analyzed to compare the effects of low and very low starting doses of L-thyroxine given to the first patients in the study. A comparison of children started with an L-thyroxine dose of 5.0 μg/kg or less and with 5.1 to 7.7 μg/kg indicated no differences. Similarly, comparisons between the HDG and all children receiving the lower dose versus only those receiving a moderate dose (i.e., "knocking out" the lowest doses) also indicated no differential effects. Therefore
DISCUSSION
These findings indicate that, in the treatment of CH, better intellectual outcome is associated with a higher starting dose of L-thyroxine. Particularly affected are verbal and memory competencies, as well as reading comprehension; perceptual skills are generally less affected. The relationships are not linear, but a threshold effect is indicated: children at the lowest dose levels (<5.0 μg/kg) did not differ from those with moderately low levels, whereas those at the highest dose levels (>10.0
References (37)
- et al.
Longitudinal assessment of L-thyroxine therapy for congenital hypothyroidism
J PEDIATR
(1990) - et al.
Reassessment of the daily dose of oral thyroxine for replacement therapy in hypothyroid children
J PEDIATR
(1977) - et al.
Intellectual outcome in children with fetal hypothyroidism
J PEDIATR
(1987) - et al.
Relationship of c-erbA mRNA content to tissue triiodothyronine nuclear binding capacity and function in developing and adult rats
J Biol Chem
(1990) - et al.
Effects of thyroid state on serotonin, 5-hyroxyindolacetic acid and substance P contents in discrete brain nuclei of adult rats
Neuroscience
(1983) Effects of dysthyroidism on central catecholaminergic neurons
Neurochem Int
(1985)- et al.
Bone mass in children with congenital hypothyroidism (CHT) [Abstract]
Pediatr Res
(1994) - et al.
Traitement des hypothyroidies congenitales par la L-thyroxine en solution
Arch Fr Pediatr
(1983) - et al.
Outcome following lower L-thyroxine dose for treatment of congenital hypothyroidism
Pediatr Res
(1994) - et al.
Should all patients with congenital hypothyroidism (CH) be treated with 10-15 μg/kg · day of levothyroxine(T4)
Pediatr Res
(1994)
Newborn screening for congenital hypothyroidism: recommended guidelines
Pediatrics
Newborn screening for congenital hypothyroidism: recommended guidelines
Pediatrics
Guidelines for neonatal screening programmes for congenital hypothyroidism
Eur J Pediatr
Evaluation of sodium L-thyroxine (T4) requirements in replacement therapy of hypothyroidism
J PEDIATR
Correlation of cognitive test scores and adequacy of treatment in adolescents with congenital hypothyroidism
J PEDIATR
The effect of thyroid hormone on temperament in infants with congenital hypothyroidism detected by newborn screening
J PEDIATR
Long-term neurodevelopmental correlates of treatment adequacy in screened hypothyroid children
Pediatr Res
The best way to screen for neonatal hypothyroidism
Diagn Med
Cited by (0)
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From the Department of Pediatrics (Endocrinology Division) and the Department of Psychology, University of Toronto and Hospital for Sick Children, Toronto, Canada
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Supported in part by research grants to Drs. Rovet and Ehrlich from the Ontario Mental Health Foundation and the Ontario Ministry of Health.
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Reprint requests: Joanne F. Rovet, PhD, Department of Psychology, Hospital for Sick Children, 555 University Ave., Toronto, Ontario M5G 1X8, Canada.
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0022-3476/95/$3.00 + 0 9/20/61659