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S Heyerdahl

Publications and source records attributed to S Heyerdahl.

11 recordsLinked to original sources
PubMed1997

Linear growth in early treated children with congenital hypothyroidism.

Length/height was studied from birth to 6 years of age in 103 children with congenital hypothyroidism identified by the Norwegian or Swedish screening programs. We used the "infancy-childhood-puberty (ICP) growth model". This model describes normal linear growth during the first 3 years of life by an infancy component with the addition of a childhood component, the latter acting from the second half of the first year. In comparison with reference children, children with hypothyroidism had reduced growth from 6 to 12 months, and increased growth after 12 months of age. Mean onset of the childhood component of growth was delayed from 8.1 months (SD 1.9) to 10.4 months (SD 2.2) in girls, and from 8.9 months (SD 2.0) to 11.0 months (SD 2.1) in boys. Age at onset of the childhood component was correlated with age at start of treatment (r = 0.24), and in children with more severe hypothyroidism (pretreatment serum thyroxine < 40 nmol/l) inversely correlated with the L-thyroxine dose at start of treatment (r = -0.40). Change in height standard deviation score from 1 to 3 years of age was correlated with the serum thyroxine concentration at age 1 year (r = 0.30). The delay in the onset of the childhood component of growth and the association with age at start of treatment and initial L-thyroxine dose indicate that thyroid hormones during the first months of life are essential for normal onset of the childhood component of growth, which otherwise is assumed to be growth hormone-dependent.

Age Factors↗
PubMed1996

Treatment variables as predictors of intellectual outcome in children with congenital hypothyroidism.

UNLABELLED: The purpose of this study was to assess how much of the variance in intellectual outcome at 2 and 6 years of age could be attributed to treatment variables in children with congenital hypothyroidism, and which of the parameters used for monitoring treatment predicted later development. Forty-five children, early treated according to general recommendations, were studied. Linear multiple regression analysis was used, controlling for socio-economic status and the pretreatment serum thyroxine concentration. At 2 years of age, 19% of the variance in Mental Development Index (Bayley Scales of Infant Development) was attributed to treatment variables: combinations of serum thyroxine and serum TSH during the 1st year and bone age at mean age 1.5 years (mean z-scores). At 6 years of age, 35% of the variance in Verbal IQ (Wechsler Preschool and Primary Scale of Intelligence) was attributed to treatment variables: 13% to the mean serum thyroxine concentration during the 1st year, 12% to the initial L-thyroxine dose per kilogram body weight per day, and 10% to a combined measure for serum thyroxine and serum TSH during the 2nd year (mean z-score). CONCLUSION: Both the initial L-thyroxine dosage and treatment variables during the 1st and the 2nd year (serum thyroxine, serum TSH and bone age) predicted later intellectual outcome in children with congenital hypothyroidism.

Child↗
PubMed1995

[Screening of newborn infants in Norway for severe metabolic disease].

The objective of neonatal screening for phenylketonuria and congenital hypothyroidism is early diagnosis and initiation of treatment to prevent brain damage and mental retardation. We present the results of the Norwegian national neonatal screening programme for phenylketonuria and congenital hypothyroidism. Screening for phenylketonuria based on serum phenylalanine determinations started in 1967 and covered the whole country in 1978. National screening for congenital hypothyroidism started in 1979. One hundred children with phenylketonuria and 280 children with a strong indication of congenital hypothyroidism have been detected up to 1 October 1994. Screening-related challenges and principles of treatment are discussed.

Congenital Hypothyroidism↗
PubMed1995

Significance of elevated serum thyrotropin during treatment of congenital hypothyroidism.

Serum thyrotropin concentrations are frequently elevated during treatment of children with congenital hypothyroidism. It is unclear if elevated thyrotropin during early treatment indicates non-optimal treatment. In a cohort of 49 children with congenital hypothyroidism, we studied the decline in serum thyrotropin concentration after initiating L-thyroxine treatment, the relationship between elevated thyrotropin and treatment variables, and non-compliance with the treatment as a possible cause of elevated thyrotropin. The initial mean dose of thyroxine was 8.5 (SD 3.3) micrograms/kg body weight/day: 71% of the serum samples obtained 15-21 days after the start of treatment had serum thyrotropin concentrations < 10 mU/l. Six children had no samples with serum thyrotropin < 10 mU/l during the first 3 months of treatment. These children had a lower thyroxine dose prescribed, and serum thyrotropin was normalized when the dose was sufficiently increased. During treatment, from 6 weeks of age, serum thyrotropin > 10 mU/l was related to a lower dose of thyroxine and lower serum thyroxine, and was not due to non-compliance with treatment.

Cohort Studies↗
PubMed1994

Skeletal maturation during thyroxine treatment in children with congenital hypothyroidism.

The aim of this investigation was to study if bone age development (assessed by the Greulich & Pyle atlas) was related to L-thyroxine treatment in 47 children with congenital hypothyroidism, treated early and according to general recommendations. In spite of frequent delay in skeletal maturation at diagnosis, the delay in mean bone age at a mean chronological age of 1.5 years was slight (0.5 months), and 30% of the variation in bone age SD score (SDS) at 1.5 years was accounted for by the dose of L-thyroxine and serum thyroxine during the first year. The children with a bone age within +/- 1 SDS had a prescribed mean dose of L-thyroxine per kg body weight from 3 to 12 months of age of 5.4 +/- 1.7 micrograms/kg/day, and their mean serum thyroxine concentration during the first year was 175 +/- 29 nmol/l. We conclude that bone age at 1.5 years of age was positively correlated with the dose of L-thyroxine and the serum thyroxine concentrations during the first year. This supports the general use of bone age assessments as a complement to other treatment variables in the follow-up of children with congenital hypothyroidism.

Age Determination by Skeleton↗
PubMed1991

Intellectual development in children with congenital hypothyroidism in relation to recommended thyroxine treatment.

The relationship between the treatment serum thyroxine level and intellectual development at 2 and 6 years was investigated in 46 Norwegian children with congenital hypothyroidism identified by neonatal screening. The level of serum thyroxine during the first 2 years was positively correlated with the Mental Development Index at 2 years of age (Bayley Scales of Infant Development) and the Verbal IQ at 6 years of age (Wechsler Preschool and Primary Scale of Intelligence). Children with a mean serum thyroxine level greater than 180 nmol/L (14 micrograms/dl) during the first year had a significantly higher Mental Development Index at 2 years and Verbal IQ at 6 years than children with serum thyroxine values less than 129 nmol/L (10 micrograms/dl). Boys had a lower Mental Development Index at 2 years of age than girls (86.9 vs 105.1; p less than 0.001) and a higher frequency of elevated serum levels of thyroid-stimulating hormone during the first year (p = 0.001). No signs of toxic effects of a high hormone level at the time of IQ assessment were detected. However, high serum levels of thyroxine at ages 2 to 4 years in girls were related to lower Performance IQ at age 6 years. The results demonstrate that the serum level of thyroxine is of importance in relation to intellectual development. Thyroxine levels above the upper reference range during the first 2 years were related to best intellectual development at 2 and 6 years.

Analysis of Variance↗
PubMed1989

[Children with phenylketonuria (Fölling's disease). Intellectual functions and psychological adaptation].

Untreated phenylketonuria (PKU) leads to serious mental retardation. The prognosis of PKU has been dramatically improved by neonatal screening and dietary treatment. This study evaluates 25 children, ages 10 to 16 years. Children who receive early and adequate treatment have a mean IQ slightly below normal, and few psychological problems. The disease causes considerable strain on the families, however, because of the very strict diet. Recent evidence suggests that children with PKU can only rarely terminate the diet, although in many cases the diet can be relaxed. It is essential to teach the children the diet and promote autonomy in relation to phenylketonuria.

Adaptation, Psychological↗