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Reference : Endemic goitre is a primary pathology of thyroid gland and critical medico social problem in many c    more

Reference : Endemic goitre is a primary pathology of thyroid gland and critical medico social problem in many countries. A dominant cause of endemic goitre is iodine deficiency. However, besides primary iodine deficiency, the goitre may develop due to effects of bioelement imbalances, essentional to the thyroid function maintenance. Here we studied 44 cases of endemic goitre in prepubertal children (7-10 y.o.) living in iodine-adequate territory. Thyroid volume was estimated by ultrasonometry. Main bioelements (Al, Ca, Cd, Co, Cr, Cu, Fe, Hg, I, Mg, Mn, Pb, Se, Si, Zn) were determined in hair samples by ICP-OES/ICP-MS method. The bioelement effects on thyroid gland were estimated by multiple regressions. The regression model revealed significant positive relations between thyroid volume and Cr, Si, Mn contents. However, the actual factor of thyroid gland increase was only Si excess in organism. Significant negative relations of thyroid volume were revealed with I, Mg, Zn, Se, Co and Cd. In spite of this, the actual factors of thyroid gland volume increasing were I, Co, Mg and Se deficiency. Total bioelement contribution in thyroid impairment was estimated as 24%. Another 76% fell at non-model factors like endocrine profile, metabolic status, climatic causes etc. Thus, it was proved that endemic goitre in iodine-adequate territory can be formed by bioelement imbalances, namely Si excess and Co, Mg, Se shortage as well as endogenous I deficiency in spite of iodine-adequate environment.    less

Abstract : Introduction. Endemic goitre is an important medico-social problem over the world. It is a primary    more

Abstract : Introduction. Endemic goitre is an important medico-social problem over the world. It is a primary pathology of thyroid gland and critical disease in many countries (1-4). According to classical point of view, the cause of endemic goitre is iodine deficiency of various origins. But, it is known, that in some regions the severity of endemia is not corresponding to iodine deficiency level. Iodine prophylaxis there decreases the severity of endemic goitre, but not cures it finally [12,13]. Besides that, endemic goitre in iodine adequate or even iodine enriched regions occurs also. By modern knowledge, besides iodine deficiency, among the leading goitrogenic (or strumogenic) biogeochemical factors are excesses or deficiencies in the biosphere of some trace elements, controlling synthesis of iodinated hormones (5, 6). In some biogeochemical provinces, combination of low iodine provision and thyrospecific trace element imbalances can disturb the iodine accumulation and metabolism in human body and, as a result, cause endogenous deficiency of iodine. So, the compensatory enlargement of thyroid gland and appearance of goitre can occur. Recently, we found, that hair iodine content can be used as an individual test, reflecting body iodine provision (7). According to our data, the average thyroid gland volume in population of iodine-deficient and iodine-adequate regions of European North and Far East of Russia was very well correlated to hair iodine level, as compared to urine iodine concentration, so called ioduria. The aim of this work was to investigate the role of bioelements (through multielement hair analysis) in occurrence of endemic goitre in children, living in iodine-adequate territory of European North of Russia, White Sea coast, the Archangelsk region. Materials and methods Totally, 44 prepubertal children were investigated. The multielement hair content (Al, Ca, Cd, Co, Cr, Cu, Fe, Hg, I, Mg, Mn, Pb, Se, Si, Zn) was determined by combined methods of atomic emission and mass spectrometry with inductively coupled argon plasma (ICP-OES/ICP-MS) (8). Also, the individual iodine excretion by urine was assayed by routine Ce-arsenite method, and thyroid gland volume was evaluated by ultrasonometry. The bioelement effects on thyroid gland were estimated by regression analysis; the statistical calculations were performed using Statistica 6.0 application package (StatSoft Inc., USA). Results and discussion As it was shown, the median of iodine excretion in the seacoast region’s children was 101.2 mg/L, within the normal range according to WHO recommendations. So, it suggests the sufficient or adequate I provision here (9). Thyromegalia or diffuse thyroid gland enlargement in the observed territory was found in 16.7% of children. It is 3 fold higher than epidemic limit (5%). These data suggest the light degree of endemic goitre. So, the foreland territory is iodine-adequate or sufficient in iodine provision on the one hand, and endemic in goitre on the other hand, simultaneously. A paradox? Such an inconsistency between normal level of iodine provision and existence of endemic goitre points to endogenous iodine deficiency. Table 1 presents human hair multielement analysis data. It can be seen there, that medians of Mg, I, Mn, Se, Cr and Co content are lower than normal range, lower than physiologically allowable levels. But, this is interesting to note, that decreased hair iodine content occurs only in 59% of all investigated cases, on the other hand all children have lower hair Co and Se, 93% have lower hair Cr, 89% have lower hair Mg and 73% have lower hair Mn. In 25% off all cases the exceeding of hair biologically allowable Si level was found. So, the children population, in both iodine-adequate (following ioduria data) seacoast territory and endemic goitre territory, have a lot of mineral imbalances, reflected in hair elemental content. A regression model of thyroid gland volume depending from bioelements concentration was made. In result, the presented formula was obtained. Y=8,59–1,5×I–0,12×Mg–0,018×Zn–1,27×Se–178×Co+6,21×Cr+0,08×Si+2,74×Mn–8,05×Cd (F=3.86; p<0.05; R2=0.83), where Y is thyroid volume. The formula provides prognosis of thyroid volume on the basis of some hair mineral content data. This reports predictable anticipated values of thyroid gland volume in dependence of given bioelements concentration: I, Mg, Zn, Se, Co, Cr, Si, Mn, Cd. In regression model were revealed significant positive relations of thyroid gland volume with Cr, Si, Mn values. However, the actual factor of thyroid gland volume increase was only Si excess in organism. Significant negative relations of thyroid gland volume were revealed with I, Mg, Zn, Se, Co and Cd. In spite of this, the actual factors of thyroid gland volume increase was I, Co, Mg and Se deficiency. There was estimated the degree of bioelement impacts on thyroid gland volume. The total bioelement contribution was 24%. Another 76% fell at non-model factors like endocrine profile, metabolic status, environment climatic causes etc. The impact of each taken bioelement from total contribution was 11.6 % for Si, 10.4 % for I, 9.6 % for Co, 9.3 % for Mg and 2.7 % for Se. The validity of the proposed mathematical model is suggested by individual testing. The calculated and real volumes of thyroid glands in children were the same in 83% of all cases. This model also suggests, that lack or excess of trace elements in the body reflecting by human hair trace element content, are important factors, influencing on thyroid gland size. Thus, it was proved that endemic goitre in iodine-adequate territory was formed by bioelement imbalances. The significant role in thyroid gland volume increasing belongs to Si excess and Co, Mg, Se shortage as well as to endogenous iodine deficiency in spite of iodine-adequate environment. References 1. Gerasimov G., Judenitch O., Dedov I. Iodine Deficiency in Europe. New York: Eds. F. Delange et al., 1993. 2. Delange F. Iodine deficiency in Europe and its consequences: an update. Eur J Nucl Med Mol Imaging 2002; 29: 404-16. 3. Hetzel B. Iodine deficiency: a global problem. Med J Aust. 1996; 1: 28-9. 4. Zimmermann M., Molinari L., Spehl M. Toward a consensus on reference values for thyroid volume in iodine-replete schoolchildren: results of a workshop on inter-observer and inter-equipment variation in sonographic measurement of thyroid volume. Eur J Endocrinol. 2001; 3: 213-20. 5. Arthur J., Beckett G. Thyroid function. Br Med Bull. 1999; 3: 658-68. 6. Gaitan E., Cooksey R., Legan J. Antithyroid and goitrogenic effects of coal-water extracts from iodine – sufficient goiter areas. Thyroid 1993; 1: 49-53. 7. Gorbachev AL, Skalny AV, Bulban AP, Lomakin UV. Parameters of iodine deficiency in various climatic areas of the north according to the analysis of iodine in urine and hair. Proceed. of the 2nd Intern.Conf. «Bioelements», Orenburg, Russia, 2006. p.235-9. [in Russia]. 8. Serebryansky A.P., Skalny A.V., Timofeev P.V. Combined approach to elemental hair analysis by ICP-AES and ICP-MS. // Proceed. of 4th Intern.symp. on trace elements in human: new perspectives, Athens, Greece, 9-11 October, 2003. Athens, 2003; II: 1365–1370. 9. WHO, UNICEF and ICCIDD. Assessment of the Iodine deficiency disorders and monitoring their elimination // Geneva: WHO, WHO/Euro/NUT. 2001. P. 1 - 107. 10. Demidov VA., Skalny AV. Children’s hair trace element concentrations in Moscow region. // 3rd Intern. Symp. on trace elements in human: new perspectives. October 4–6, 2001, Athens, Greece, p. 510–521. 11. Iyengar GV., Woittiez J. Trace elements in human Clinical Specimens: Evaluation of Literature Date to identify Reference Values. // Clin Chem., 1988, P.474-81. 12. Mocan MZ., Mocan H., Tocel S. Possible effects of trace elements in the etiology of endemic goiter in the northeast of Turkey // Trace Elem.Med. 1989; 6 (1):4 – 8. 13. Dedov II, Sviridenko NY. Strategy of liquidation of iodine deficient diseases in Russian Federation. Probl. Endocrinol. 2001;6: 3-12 [in Russian]. Table 1. The median of hair bioelement value in children living in foreland of Arkhangelsk region Element concentrations (mcg/g) Biologically permissible level a Low bound High bound Al 8.9 2.0 40.0 Ca 210.7 200 1500 Cd 0.03 0 0.5 Co 0.008 0.2 1.0 Cr 0.3 0.5 1.5 Cu 9.0 6.5 15.0 Fe 16.5 15.0 50.0 Hg 0.1 0 1.0 I 0.15 0.42 a 2.7 b Mg 17.6 25 120 Mn 0.3 0.5 3.0 Pb 0.7 0 5.0 Se 0.4 0.8 3.0 Si 19.8 5 30 Zn 170.2 125 250 a V. Demidov, ?. Skalny, 2001 [10]. b V. Iyengar, J. Woittiez, 1988 [11]. - Slides    less