Standardized Map of Iodine Status in Europe.

Background: Knowledge about the population's iodine status is important, because it allows adjustment of iodine supply and prevention of iodine deficiency. The validity and comparability of iodine-related population studies can be improved by standardization, which was one of the goals of the EUthyroid project. The aim of this study was to establish the first standardized map of iodine status in Europe by using standardized urinary iodine concentration (UIC) data. Materials and Methods: We established a gold-standard laboratory in Helsinki measuring UIC by inductively coupled plasma mass spectrometry. A total of 40 studies from 23 European countries provided 75 urine samples covering the whole range of concentrations. Conversion formulas for UIC derived from the gold-standard values were established by linear regression models and were used to postharmonize the studies by standardizing the UIC data of the individual studies. Results: In comparison with the EUthyroid gold-standard, mean UIC measurements were higher in 11 laboratories and lower in 10 laboratories. The mean differences ranged from -36.6% to 49.5%. Of the 40 postharmonized studies providing data for the standardization, 16 were conducted in schoolchildren, 13 in adults, and 11 in pregnant women. Median standardized UIC was <100 µg/L in 1 out of 16 (6.3%) studies in schoolchildren, while in adults 7 out of 13 (53.8%) studies had a median standardized UIC <100 µg/L. Seven out of 11 (63.6%) studies in pregnant women revealed a median UIC <150 µg/L. Conclusions: We demonstrate that iodine deficiency is still present in Europe, using standardized data from a large number of studies. Adults and pregnant women, particularly, are at risk for iodine deficiency, which calls for action. For instance, a more uniform European legislation on iodine fortification is warranted to ensure that noniodized salt is replaced by iodized salt more often. In addition, further efforts should be put on harmonizing iodine-related studies and iodine measurements to improve the validity and comparability of results.

Chromogranin A in the Laboratory Diagnosis of Pheochromocytoma and Paraganglioma.

This work discusses the clinical performance of chromogranin A (CGA), a commonly measured marker in neuroendocrine neoplasms, for the diagnosis of pheochromocytoma/paraganglioma (PPGL). Plasma CGA (cut-off value 150 µg/L) was determined by an immunoradiometric assay. Free metanephrine (cut-off value 100 ng/L) and normetanephrine (cut-off value 170 ng/L) were determined by radioimmunoassay. Blood samples were collected from PPGL patients preoperatively, one week, six months, one year and two years after adrenal gland surgery. The control patients not diagnosed with PPGL suffered from adrenal problems or from MEN2 and thyroid carcinoma. The clinical sensitivity in the PPGL group of patients (n = 71) based on CGA is 90% and is below the clinical sensitivity determined by metanephrines (97%). The clinical specificity based on all plasma CGA values after surgery (n = 98) is 99% and is the same for metanephrines assays. The clinical specificity of CGA in the control group (n = 85) was 92% or 99% using metanephrines tests. We can conclude that plasma CGA can serve as an appropriate complement to metanephrines assays in laboratory diagnosis of PPGL patients. CGA is elevated in PPGLs, as well as in other neuroendocrine or non-neuroendocrine neoplasia and under clinical conditions increasing adrenergic activity.

[Thyroid disease in the Czech Republic: the EUthyroid project and the evaluation of the General Health Insurance Company epidemiological data for the period of 2012-2015]. / Onemocnení stítné zlázy v Ceské republice: projekt EUthyroid a vyhodnocení epidemiologických dat VZP za období let 2012-2015.

Institute of Endocrinology participates in the grant of European Commission EUthyroid (Towards the elimination of iodine deficiency and preventable thyroid-related diseases in Europe), together with other 28 European countries. The role of Institute of Endocrinology in EUthyroid is among other things to ensure access to national registers relating to thyroid diseases. The results presented here correspond to the years 2012-2015 and are based on data from the General Health Insurance Company Czech Republic (VZP CR), which has 6 million insured persons (ratio male : female = 1 : 1). The set is sufficiently representative to be related to the whole of the Czech Republic. According to VZP data, the prevalence of thyreopathies is constantly increasing, for example according to the code of diagnoses E00-E07 and the unique birth number, the prevalence of thyreopathies increased from 6.8 % in 2012 to 7.5 % in 2015. The increase of the prevalence is mainly concentrated to clinical manifestation of hypothyroidism (code E03, an increase from 2.8 % in 2012 to 3.2 % in 2015); the second is nontoxic struma (code E04), which had a constant prevalence of 2.5 % in the given period. On the other hand, thyroiditis (code E06), the third in the order of occurrence, increased from 1.8 % in 2012 to 2 % in 2015. The decrease in prevalence only occurred in hyperthyroidism (E05) from 0.7 % in 2012 to 0.6 % in 2015. Other thyreopathies had a prevalence of less than 1 %, and was constant between 2012 and 2015 (other thyroid disorders E07 0.8 %, thyroid disorders associated with iodine deficiency E01 0.2 %, E02 0.07 %, E00 0.01 %, thyroid carcinoma C73 0.13 %).Key words: EUthyroid - General Health Insurance Company- occurrence of thyreopathies - thyroid disease in the Czech Republic.

Urinary iodine concentrations in mothers and their term newborns in country with sufficient iodine supply.

OBJECTIVE: The main aim of the study was to evaluate maternal and newborn urinary iodine concentrations according to the usage of iodine supplementation during pregnancy. METHODS: Thirty-seven women with singleton uncomplicated pregnancies and their newborns were included in this study. Maternal urine samples were obtained at the time of delivery and on the third day after delivery. Newborn urine samples were obtained on the third day after delivery. Urinary iodine concentrations were determined by the alkaline ashing of urine specimens followed by the Sandell-Kolthoff reaction using brucine as a colorimetric marker. RESULT: The overall rate of the usage of iodine supplementation during pregnancy was 54% (20/37). Women who used the iodine supplementation during the pregnancy did not have different urinary iodine concentrations neither at the time of delivery (p = 0.23), nor on the third day after delivery (p = 0.65) in comparison to women without extra iodine supplementation. Newborns from pregnancies with regular iodine supplementation had higher urine iodine concentrations on the third day after delivery (p = 0.02). When women were split into several subgroups based on the daily dosage of iodine supplementation (200, 150, and 50 µg daily and without iodine supplementation), no differences were found in maternal urine iodine concentrations at the time of delivery (p = 0.51) and on the third day after delivery (p = 0.63). Different levels were found in newborn urine iodine concentrations among the subgroups of newborns from pregnancies with different daily doses of iodine supplementation and from pregnancies without iodine supplementation during pregnancy (p = 0.05). CONCLUSIONS: Iodine supplementation during pregnancy affects newborn urine concentrations but not maternal urine concentrations.

[Iodine supply of pregnant women in the Czech Republic]. / Zásobení jodem u tehotných zen v Ceské republice.

INTRODUCTION: Iodine deficiency is a global public health problem which is particularly noticeable in pregnant or breastfeeding women and their children. Even mild iodine deficiency during pregnancy can lead to damage to the developing brain and thus affecting the fetus intelligence, his cognitive and neurological function, embryogenesis and growth. PATIENTS: In the period 2010-2015 was determined by spectrophotometry at the Institute of Endocrinology the basal urinary iodine in 532 pregnant women at the age of 32 ± 5 (18-44) years, which came from Prague, Hradec Kralove and Mlada Boleslav. It was located 349 women in the first trimester, 112 in the second trimester, and 71 women in the third trimester. In the monitoring of pregnant women in the first trimester 218 basal urine samples of women were determined by mass spectrometry with inductively coupled plasma (ICP MS) in The National Institute of Public Health (NIPH). Women came from the 6 areas in the Czech Republic. Development of urinary iodine in the general population in the period 1994-2015 was observed in patients who underwent Institute of Endocrinology and from population studies conducted in 7 regions of the Czech Republic. It performed 52 648 spectrophotometric analysis of urinary iodine in the general population. METHODS: Urinary iodine was determined by alkali melting of urine samples, followed by spectrophotometric determination of iodine in the form of iodide using the Sandell-Kolthoff reaction in the Institute of Endocrinology or determination was performed by ICP-MS in the laboratory of NIPH. RESULTS: On average, only 21.8 % of pregnant women had urinary iodine values determined by spectrophotometry higher than 150 µg/L. The results of iodine nutrition of pregnant women in the first trimester analyzed using ICP-MS are better, but even so, only 50.5 % of pregnant women have urinary iodine higher than 150 µg/L. CONCLUSION: The results of iodine nutrition of pregnant women are alarming, on average, only 30 % of the total of 750 examined women have urinary iodine values greater than 150 µg/L and therefore meet the requirements of the WHO for pregnant women. Our results, however, show that iodine deficiency is not major public health problem in the general population.Key words: ICP-MS - pregnant women - Sandell-Kolthoff reaction - urinary iodine.

The significance of plasma adrenomedullin and calcitonin gene-related peptide concentration in patients with Type 2 diabetes mellitus who are treated for cardiovascular risk factors.

OBJECTIVES: To evaluate the significance of plasma adrenomedullin and calcitonin gene-related peptide (CGRP) concentration in patients with Type 2 diabetes mellitus who are treated for hypertension and dyslipidemia. METHOD: Plasma adrenomedullin and CGRP concentration, transthoracal echocardiography and ABPM were evaluated in 82 patients with Type 2 diabetes mellitus and 41 control subjects with no previous cardiovascular disease. All the subjects had casual blood pressure ≤140/90 mmHg or received antihypertensive medication, were treated by statin if LDL cholesterol was≥3mmol/L, by fibrates if triacylglyceroles≥2 mmol/L. RESULTS: The mean age was 61±6 in patients with diabetes mellitus and 61±5 years in control subjects (p=0.9). Plasma CGRP was 3.0±1.8 in patients with diabetes mellitus and 2.3±1.0 ng/ml in control subjects (p=0.09). Plasma adrenomedullin was 2.2±0.9 in patients with diabetes mellitus and 2.8±1.1 ng/ml in control subjects (p=0.01). In patients with diabetes mellitus mass index of the left ventricle was significantly higher and the parameters of diastolic function were more deteriorated. Plasma adrenomedullin and CGRP correlated significantly negatively with serum creatinine and positively with mean 24 hours arterial blood pressure in patients with diabetes mellitus but not in control subjects. Plasma adrenomedullin concentration in patients with diabetes mellitus treated for hypertension was significantly reduced. CONCLUSION: Despite concentration plasma adrenomedullin and CGRP modulation by cardioprotective treatment both neuropeptides remained involved in regulation of hemodynamic and metabolic parameters in patients with Type 2 diabetes mellitus. The low plasma of adrenomedullin in patients with Type 2 diabetic may be marker of the efficient intervention on cardiovascular risk factors.

Mild iodine deficiency in women after spontaneous abortions living in an iodine-sufficient area of Czech Republic: prevalence and impact on reproductive health.

OBJECTIVE: Iodine deficiency is associated with thyroid dysfunction and adverse pregnancy outcomes. The aim of our study was to investigate the status of iodine saturation in women after spontaneous abortion (SpA) residing in an iodine-sufficient area and to evaluate their subsequent reproductive health. DESIGN: Nonrandomized prospective follow-up study. PATIENTS AND METHODS: We compared urinary iodine concentration (UIC) in 171 women 2-8 weeks (median 4) after an early SpA with age-matched controls. Women with known thyroid diseases were excluded. We also analysed a relationship of UIC to serum thyroid-stimulating hormone, free thyroxine, antibodies against thyroid peroxidase and thyroid ultrasound. Afterwards, we followed the women for a median of 38 months (range 12-47). We used a multivariate regression analysis to assess the influence of iodine status and other thyroid biochemical and ultrasound parameters on their subsequent reproductive health. RESULTS: Women after SpA were almost twice as likely to suffer from mild iodine deficiency and had lower median UIC as compared to age-matched controls [rate 105/181 (58·0%) vs 57/181 (31·5%), P < 0·001, medians UIC 92·00 vs 117·80 mcg/l, P < 0·001]. UIC was not influenced by the use of iodine supplements in the previous pregnancy. We did not find any association neither between UIC and thyroid dysfunction and/or thyroid antibodies, nor between UIC and rates of subsequent successful pregnancies or obstetric complications. CONCLUSIONS: More than half of women after SpA residing in an iodine-sufficient area are suffering from mild iodine deficiency. However, it does not seem to have a negative impact on their subsequent reproductive health.

Dysthyronemia in normal concentrations of thyrotropin--analytical and clinical consequences.

This article discusses the conditions that may lead to a phenomenon called dysthyronemia. Here, the thyroid gland has concentration of thyrotropin in circulation within the reference range, but the concentrations of free or total fractions of thyroid hormones are outside the reference range. Normal values of thyrotropin (TSH) and increased values of THs are referred to as hyperthyroxinemia, while normal values of thyrotropin and decreased values of thyroid hormone are hypothyroxinemia. As shown by our observations, it is a relatively frequent situation in the parallel determinations of TSH and free thyroxine, when results verging on hyperthyroxinemia were found in 7% of cases (6.74%, n=259,590), and also in the parallel sets of TSH and total triiodothyronine when hypotriiodothyroninemia reached 8.5% (8.48%, n=73,143). We are assuming that the main cause of hyperthyroxinemia in the free thyroxine and TSH system is the presence of autoantibodies against thyroxine in patients with autoimmune thyroid disease. The reason of hypotriiodothyroninemia in the system of triiodothyronine and TSH is a decreased concentration of thyroid binding globulin in postmenopausal women. Manufacturers of immunoanalytical kits should take into account the potential adverse effects of autoantibodies against thyroid hormones when measuring the results of immunoassay determination of the free fraction of these hormones.

Evaluation of dysthyronemia in endocrinological patients.

BACKGROUND: Dysthyronemia is the state of the thyroid gland in which the concentration of thyrotropin (TSH) in circulation is within the reference range, but the concentrations of free or total fractions of thyroid hormones (TH) are outside the reference range. Normal values of TSH and increased values of TH are referred to as hyperthyroxinemia or hypertriiodothyroninemia, while normal values of TSH and decreased values of TH are called hypothyroxinemia or hypotriiodothyroninemia. METHODS: Thyroid diagnostic tests were carried out at the Institute of Endocrinology, Prague, Czech Republic, in 1999-2009 using the immunoanalytical systems of Roche Diagnostics GmbH, Germany (Elecsys 2010, Modular E170). RESULTS: Hyperthyroxinemia was found in 6.74% of all parallel sets of TSH and free thyroxine (FT4, n=259,590) values. Hypotriiodothyroninemia was observed in 8.48% of all parallel sets of TSH and total triiodothyronine (TT3, n=73,143). The occurrence of hyperthyroxinemia (TSH-FT4) and hypotriiodothyroninemia (TSH-TT3) was >3 times higher than the occurrence of dysthyronemia for the combinations TSH-FT4 (hypothyroxinemia), TSH-TT4 (total thyroxine, n=1996), TSH-FT3 (free triiodothyronine, n=94,090), and TSH-TT3 (hypertrijodthyroninemia), and >5 times higher in comparison with the combinations TSH-FT4-FT3 (n=93,683), TSH-FT4-TT3 (n=72,373), TSH-FT3-TT3 (n=2466), TSH-TT4-TT3 (n=1779), TSH-FT4-TT4 (n=1571), and TSH-FT3-TT4 (n=1466). CONCLUSION: In light of our patient types, we are assuming that the observed hypotriiodothyroninemia (TSH-TT3, 8.48%) is due to a decreased concentration of thyroid binding globulin in postmenopausal women and that hyperthyroxinemia (TSH-FT4, 6.74%) is caused mainly by endogenous autoantibodies against thyroxine in patients with thyroid autoimmune diseases.

Congenital adrenal hyperplasia and the function of adrenal medulla.

OBJECTIVE: The most common form of congenital adrenal hyperplasia (CAH) is the deficiency of steroid 21-hydroxylase which results from deletion or mutation of the cytochrome P450 21-hydroxylase gene. The low level of glucocorticoids and in some cases low level of mineralocorticoids has an important pathophysiological influence on the axis of the hypothalamo-pituitary-adrenal cortex. DESIGN: Using determination of plasmatic metanephrine, normetanephrine and chromogranin A, we wanted to investigate the structure and function of adrenal medulla in patients with CAH, because adrenocortical and adrenomedullary systems are intimately linked anatomically and functionally. METHODS: Levels of plasmatic metanephrine, normetanephrine and chromogranin A were measured in our group of 37 patients (age range: 5-45 years, 18 females and 19 males) with the classic salt-wasting form of CAH. RESULTS: The reference range was 73% for metanephrine (<10 ng/L, 83.3% females, 63.2% males) and 59.5% for metanephrine (<15 ng/L, 72.2% females, 47.4% males). The concentration of plasmatic nephrines in the first quartile reference range was achieved in the case of metanephrine in all patients (<23 ng/L), and in the case of normetanephrine in 86.5% of patients (<42.5 ng/L). The level in chromogranin A was normal in all patients. No significant differences were found in plasmatic concentrations of nephrines and chromogranin A between males and females with CAH, nor was there a significant correlation with genetic results (severe or moderate salt-wasting form of CAH). CONCLUSION: Impaired secretion of glucocorticoids in patients with CAH leads to the structural changes in adrenal medulla which are expressed by low production of metanephrine, and to a lesser extent, normetanephrine.

RET mutation Tyr791Phe: the genetic cause of different diseases derived from neural crest.

Activating germline RET mutations are presented in patients with familial medullary thyroid carcinoma (FMTC) and multiple endocrine neoplasia (MEN) types 2A and 2B, whereas inactivating germline mutations in patients with Hirschsprung's disease (HSCR). The aim of this study was to evaluate genotype-phenotype correlations of the frequently discussed Tyr791Phe mutation in exon 13 of the RET proto-oncogene. Screening of three groups of patients was performed (276 families with medullary thyroid carcinoma (MTC), 122 families with HSCR, and 29 patients with pheochromocytoma). We found this mutation in 3 families with apparently sporadic MTC, 3 families with FMTC/MEN2, 1 patient with pheochromocytoma, and 3 families with HSCR. All gene mutation carriers have a silent polymorphism Leu769Leu in exon 13. In three families second germline mutations were detected: Cys620Phe (exon 10) in MEN2A family, Met918Thr (exon 16) in MEN2B family, and Ser649Leu (exon 11) in HSCR patient. Detection of the Tyr791Phe mutation in MEN2/MTC and also in HSCR families leads to the question whether this mutation has a dual character (gain-of-function as well as loss-of-function). A rare case of malignant pheochromocytoma in a patient with the Tyr791Phe mutation is presented. This study shows various clinical characteristics of the frequently discussed Tyr791Phe mutation.

Vitamin D and its metabolites--supply of patients with various endocrine disorders and comparison of analytical methods.

OBJECTIVE: Vitamin D is important not only for its effect on the homeostasis of calcium, but also for its anti-proliferative, pro-differentiation, pro-apoptotic and immuno-modulating effects in the tissues of living organisms. This work describes the results of serum 25(OH)D (n=2175) and 1alpha,25(OH)2D (n=2271) radioimmunoassays (RIA) conducted at the Institute of Endocrinology in Prague (Czech Republic) during the period of 2004-2006. METHODS: Serum concentrations of vitamin D metabolites were determined by RIA kits from IDS Ltd., Boldon, UK. In a group of 20 healthy volunteers, results obtained using the RIA kit were compared with those obtained after serum extraction with acetonitrile, subsequent chromatographic (RP HPLC) separation of 25(OH)D and its detection in collected fractions using the same RIA kit from IDS. RESULTS: The mean concentrations +/- S.D. in the samples studied were 76.4 +/- 45.6 nmol/l for 25(OH)D and 88.9 +/- 45.1 pmol/l for 1alpha,25(OH)2D. The mean concentrations of both metabolites were higher in women than in men, but only the difference for 1alpha,25(OH)2D) was statistically significant (p=0.0000). The lowest concentrations of 25(OH)D or 1alpha,25(OH)2D were found in patients with hyperparathyroidism, the highest concentrations those treated with cholecalciferol for osteoporosis and vitamin D deficiency. The relationship between 25(OH)D and 1alpha,25(OH)2D was expressed by the equation 1alpha,25(OH)2D = 71.0845 + 0.1890 * 25(OH)D (n=1065, p=0.0000, R2=0.0343). Based on the RIA results, only 4 % of individuals were inadequately supplied with 25(OH)D, 79 % were supplied adequately and almost 17 % were supplied more than adequately. Similarly, 1alpha,25(OH)2D shows inadequate concentration in 15 % of the individuals tested, 59 % of these individuals were within the reference range and 26 % had values exceeding the upper limit of the reference range. The mean concentrations of 25(OH)D obtained by HPLC separation were in average by 8 % higher than those obtained using only the RIA kit. CONCLUSION: Interpretation of studies dealing with vitamin D stores must be based on precise and correct analytical procedures. However, only a few information exists about the influence of other vitamin D metabolites and conjugates on the concentration of immunoanalytically measured serum 25(OH)D or 1alpha,25(OH)2D.

Actual levels of soy phytoestrogens in children correlate with thyroid laboratory parameters.

Thyroid hormones and thyroid autoantibodies, along with serum concentrations of two phytoestrogens of the isoflavone series, daidzein and genistein, were measured in 268 children without overt thyroid diseases, screened for iodine deficiency in one region of the Czech Republic. Since both phytoestrogens have been reported to inhibit thyroid hormone biosynthesis and in high concentrations to exert goitrogenic effects, we investigated whether their presence in the circulation could influence thyroid hormone function in a population where soy consumption is not common. Correlation analysis revealed a significant positive association of genistein with thyroglobulin autoantibodies and a negative correlation with thyroid volume. Multiple regression analysis of the relationships between actual phytoestrogen levels and measured thyroid parameters revealed only a weak but significant association between genistein and thyroid variables. Higher levels of free thyroxine were found in a subgroup of 36 children who ate soy food in the previous 24 h. In conclusion, only modest association was found between actual phytoestrogen levels and parameters of thyroid function. On the other hand, even small differences in soy phytoestrogen intake may influence thyroid function, which could be important when iodine intake is insufficient.

Spectrophotometric determination of urinary iodine by the Sandell-Kolthoff reaction subsequent to dry alkaline ashing. Results from the Czech Republic in the period 1994-2002.

The Czech Republic is an iodine-deficient area. Insufficient iodine intake was reduced by enriching cooking salt with iodine in the range 20-34 mg I/kg. An important indicator for tracking changes in iodine nutrition over time is accurate information about urinary iodine concentrations in the population. In this paper we describe and characterize our method used for the determination of iodine in biological material, which is based on alkaline ashing of urine specimens preceding Sandell-Kolthoff reaction using brucine as a colorimetric marker. The losses of radioiodine added during sample preparation have not exceeded 0.001%. The detection limit is 2.6 microg I/L and the limit of quantification is 11.7 microg I/L, with intra-assay precision of 4% and inter-assay precision of 4.9%. During the period 1994-2002, the urinary iodine concentration was determined in 29,612 samples in the Institute of Endocrinology. The mean basal urinary iodine concentrations+/-SD were 115+/-69 microg I/L. Of the samples, 0.7% were in severe (<20 microg I/L), 9.6% in moderate (20-49 microg I/L), 40.1% in mild (50-99 microg I/L), 35.6% in adequate (100-200 microg I/L), and 14.0% in more than adequate (>200 microg I/L) subsets of iodine nutrition. A statistically significant (p<0.00001) difference was found between mean male (127 microg I/L) and female (112 microg I/L) urinary iodine, and an inversely proportional trend also exists in the age-related data.

Relationship of dehydroepiandrosterone and its 7-hydroxylated metabolites to thyroid parameters and sex hormone-binding globulin (SHBG) in healthy subjects.

The concentrations of four immunomodulatory steroids, namely dehydroepiandrosterone (DHEA), its sulfate and its 7-hydroxylated metabolites, and sex hormone-binding globulin (SHBG) and major laboratory parameters of thyroid function were determined in sera from 104 healthy females and 48 males, screened for iodine deficiency in one region of the Czech Republic. The mutual relationships of the laboratory parameters were investigated by using four statistical approaches: correlation analysis, principal component analysis, canonical correlation and linear model relationship. In addition to expected correlations among thyroid parameters and substrate-product relationships among the steroids, several new relationships were revealed: The only thyroid parameter tightly correlating with SHBG was free triiodothyronine. The latter hormone was also associated with one of the 7-OH-DHEA epimers, namely with 7beta-OH-DHEA. Thyroid hormones are known to possess thermogenic properties, as does another 7-oxygenated DHEA metabolite, 7-oxo-DHEA, the major metabolite of which is 7beta-OH-DHEA. It may indicate a link between the two thermogenic factors. The results should serve for further investigation of changes in the thyroid hormone concentrations, together with SHBG and dehydroepiandrosterone metabolites, under various pathological situations.