PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-3 (3)
 

Clipboard (0)
None
Journals
Authors
more »
Year of Publication
Document Types
1.  Pediatric reference intervals for thyroid hormone levels from birth to adulthood: a retrospective study 
Background
Age- and sex-specific reference intervals are an important prerequisite for interpreting thyroid hormone measurements in children. However, only few studies have reported age- and sex-specific pediatric reference values for TSHbasal (TSH), free T3 (fT3), and free T4 (fT4) so far. Reference intervals are known to be method- and population-dependent. The aim of our study was to establish reference intervals for serum TSH, fT3, and fT4 from birth to 18 years and to assess sex differences.
Methods
2,194 thyroid hormone tests obtained from a hospital-based pediatric population were included into our retrospective analysis. Individuals with diagnoses or medications likely to affect thyroid function were primarily excluded, as well as the diagnostic groups, if different from the purely healthy subgroup (n = 414). Age groups were ranging from 1 day to 1 month, 1 – 12 months, and 1 – 5, 6 – 10, 11 – 14, and 15 – 18 years, respectively. Levels of fT3, fT4 and TSH were measured on Advia® Centaur™ automated immunoassay system.
Results
The final sample size for reference data creation was 1,209 for TSH, 1,395 for fT3, and 1,229 for fT4. Median and 2.5/10/25/75/90/97.5 percentiles were calculated for each age group. Males had greater mean fT3 concentrations than females (p < 0.001). No sex-differences were found for TSH and fT4 between age-matched serum samples. Median concentrations of fT3, fT4 and TSH were greatest during the first month of life, followed by a continuous decline with age.
Conclusion
Our results corroborate those of previous studies showing that thyroid hormone levels change markedly during childhood, and that adult reference intervals are not universally applicable to children. Moreover, differences of our reference intervals compared to previous studies were observed, likely caused by different antibody characteristics of various analytical methods, different populations or undefined geographic covariates, e.g. iodine and selenium status.
doi:10.1186/1472-6823-8-15
PMCID: PMC2645400  PMID: 19036169
2.  The role of selenium, vitamin C, and zinc in benign thyroid diseases and of selenium in malignant thyroid diseases: Low selenium levels are found in subacute and silent thyroiditis and in papillary and follicular carcinoma 
Background
Thyroid physiology is closely related to oxidative changes. The aim of this controlled study was to evaluate the levels of nutritional anti-oxidants such as vitamin C, zinc (Zn) and selenium (Se), and to investigate any association of them with parameters of thyroid function and pathology including benign and malignant thyroid diseases.
Methods
This controlled evaluation of Se included a total of 1401 subjects (1186 adults and 215 children) distributed as follows: control group (n = 687), benign thyroid disease (85 children and 465 adults); malignant thyroid disease (2 children and 79 adults). Clinical evaluation of patients with benign thyroid disease included sonography, scintigraphy, as well as the determination of fT3, fT4, TSH, thyroid antibodies levels, Se, Zn, and vitamin C. Besides the routine oncological parameters (TG, TSH, fT4, ultrasound) Se was also determined in the cases of malignant disease. The local control groups for the evaluation of Se levels were taken from a general practice (WOMED) as well as from healthy active athletes. Blood samples were collected between 8:00 and 10:30 a.m. All patients lived in Innsbruck. Statistical analysis was done using SPSS 14.0. The Ho stated that there should be no differences in the levels of antioxidants between controls and thyroid disease patients.
Results
Among the thyroid disease patients neither vitamin C, nor Zn nor Se correlated with any of the following parameters: age, sex, BMI, body weight, thyroid scintigraphy, ultrasound pattern, thyroid function, or thyroid antibodies. The proportion of patients with benign thyroid diseases having analyte concentrations below external reference cut off levels were 8.7% of cases for vitamin C; 7.8% for Zn, and 20.3% for Se. Low Se levels in the control group were found in 12%. Se levels were significantly decreased in cases of sub-acute and silent thyroiditis (66.4 ± 23.1 μg/l and 59.3 ± 20.1 μg/l, respectively) as well as in follicular and papillary thyroid carcinoma. The mean Se level in the control group was 90.5 ± 20.8 μg/l.
Conclusion
The H0 can be accepted for vitamin C and zinc levels whereas it has to be rejected for Se. Patients with benign or malignant thyroid diseases can present low Se levels as compared to controls. Low levels of vitamin C were found in all subgroups of patients.
doi:10.1186/1472-6823-8-2
PMCID: PMC2266752  PMID: 18221503
3.  Diagnostic accuracy of basal TSH determinations based on the intravenous TRH stimulation test: An evaluation of 2570 tests and comparison with the literature 
Background
Basal TSH levels reflect the metabolic status of thyroid function, however the definition and interpretation of the basal levels of TSH is a matter of controversial debate. The aim of this study was to evaluate basal TSH levels in relation to the physiological response to i.v. TRH stimulation.
Methods
A series of 2570 women attending a specialized endocrine unit were evaluated. A standardized i.v. TRH stimulation test was carried out by applying 200 μg of TRH. TSH levels were measured both in the basal and the 30 minute blood sample. The normal response to TRH stimulation had been previously determined to be an absolute value lying between 2.5 and 20 mIU/l. Both TSH values were analyzed by cross tabulation. In addition the results were compared to reference values taken from the literature.
Results
Basal TSH values were within the normal range (0.3 to 3.5 mIU/l) in 91,5% of cases, diminished in 3,8% and elevated in 4.7%. Based on the response to TRH, 82.4% were considered euthyroid, 3.3% were latent hyperthyroid, and 14.3% were latent hypothyroid. Combining the data on basal and stimulated TSH levels, latent hypothyroidism was found in the following proportions for different TSH levels: 5.4% for TSH < 2.0 mIU/l, 30.2% for TSH between 2.0 and 3.0 mIU/l, 65,5% for TSH between 3.0 and 3.50 mIU/l, 87.5% for TSH between 3.5 and 4.0 mIU/l, and 88.2% for TSH between 4 and 5 mIU/l. The use of an upper normal range for TSH of 2.5 mIU/l, as recommended in the literature, misclassified 7.7% of euthyroid cases.
Conclusion
Our analysis strategy allows us to delineate the predictive value of basal TSH levels in relation to latent hypothyroidism. A grey area can be identified for values between 3.0 and 3.5 mIU/l.
doi:10.1186/1472-6823-7-5
PMCID: PMC1950865  PMID: 17678551

Results 1-3 (3)