Słupskie Prace Biologiczne Nr 13 ss. 55-76 2016 ISSN 1734-0926 Przyjęto: 7.11.2016 © Instytut Biologii i Ochrony Środowiska Akademii Pomorskiej w Słupsku Zaakceptowano: 16.01.2017 FIFTEEN-YEAR FOLLOW-UP OF DIFFUSE GOITER PREVALENCE AMONG ADOLESCENTS IN ENDEMIC LVIV REGION (WESTERN UKRAINE) Olha Kasiyan1 Halyna Tkachenko2 Jan Łukaszewicz3 1 Department of Hygiene and Preventive Toxicology Danylo Halytskyy Lviv National Medical University, Lviv, Ukraine e-mail: [email protected] 2 Pomeranian University in Słupsk Institute of Biology and Environmental Protection Department of Zoology and Animal Physiology Arciszewski St. 22b, 76-200 Słupsk, Poland 3 Faculty of Geographical and Geological Sciences Institute of Physical Geography and Environmental Planning Adam Mickiewicz University in Poznań ABSTRACT The aim of our study was the assessment of DG prevalence among adolescent (14- 18 years old) in Lviv region (western Ukraine) during 2000-2014. For assessment of the DG prevalence among adolescents (14-18 years old) of different districts (reions) in Lviv region during 2000-2014, the analysis of archival data from Lviv Regional Endocrinology Hospital was done. The research study covered by 20 districts (reions) of Lviv region (Brody, Busk, Horodok, Drohobych, Zhydachivskyi, Zhovkivskyi, Zolochivskyi, Kamianka-Buzka, Mykolaiv, Mostyska, Peremyshliany, Pustomyty, Radekhiv, Sambir, Skole, Sokal, Starosambirskyi, Stryiskyi, Turkivskyi, and Yavor- ivskyi Districts), as well as 6 towns of Lviv region (Lviv, Boryslav, Drohobych, Stryi, Truskavets, Chervonograd). A decrease of DG prevalence (I degree) among adoles- cents from 1747.72 to 1571.29 per 10,000 individuals during 2000-2014 was ob- served. A significant reduction of DG (I degree) prevalence among adolescents from towns of Lviv region was noted. It was 1971.74 per 10,000 individuals in 2000 and 1185.52 per 10,000 individuals in 2014. There was increased of DG (I degree) preva- lence from 1591.92 to 1785.56 per 10,000 individuals among adolescents in Lviv re- gion during 2000-2014. In 2014, the prevalence of disease among adolescents from districts was higher compared to the adolescents from towns (1785.56 compared to 55 1185.52 per 10,000 individuals, respectively). The decrease of DG (I degree) preva- lence among adolescent population in the 6 districts (Zolochivskyi, Peremyshliany, Pustomyty, Radekhiv, Starosambirskyi, Stryiskyi) and all towns (except Chervo- nograd) in Lviv region was noted. Increased DG (II and III degrees) prevalence among adolescents of Lviv region was observed in Busk, Brody, Radekhiv, Skole, and Sokal districts in 2000, in Busk, Skole, Zolo-chivskyi, Turkivskyi, and Sokal districts in 2004, in Busk, Pustomyty, Skole, Sokal, and Turkivskyi districts in 2014. The decrease of DG (II and III degrees) prevalence among adolescents in the 11 districts (Brody, Busk, Horodok, Zhydachivskyi, Zolochivskyi, Mykolaiv, Peremyshliany, Radekhiv, Sambir, Starosambirskyi, Stryiskyi) and all towns (except Drohobych and Chervo- nograd) in Lviv region was noted. In our study, we also observed that DG prevalence among adolescents in altitude regions was higher compared to the plateau regions, a finding similar to trends in previous surveys that may be explained by deficiencies in natural iodine at high altitudes and limited educational and economic support for the people who reside there. According to the present information, the prevalence of DG also was differed in districts and towns. DG are more common in districts than in the towns, which may be explained by lifestyle choices. Furthermore, females were at greater risk for DGs and this difference was not changed when females were further divided into rural, mixed and urban groups. Our results indicate the need to clarify the relevant influencing factors of DG prevalence among the population of Lviv region, the definition of the risk of thyroid pathology in each district of the region among the different age groups, which will propose measures to prevent further increase of DG incidence. Key words: Iodine Deficiency Disorders, diffuse goiter, prevalence, adolescents, Lviv region, Ukraine INTRODUCTION Endemic goiter is one of the earliest and most visible sign of iodine deficiency (WHO, UNICEF and ICCIDD: Assessment of Iodine Deficiency Disorders and Monitoring Their Elimination). According to iodine deficiency level this response may be adequate to preserve euthyroidism, but at the cost of an enlarged thyroid and the attendant risks of neck compression and eventual hyperfunctioning autonomous nodules with hyperthyroidism. An insufficient adaptation in adults produces hypo- thyroidism with its usual clinical stigmata. The damage is greater when iodine defi- ciency provokes hypothyroidism during fetal or early postnatal life, because thyroid hormone is necessary for proper development of the central nervous system, particu- larly its myelination. Individuals who were hypothyroid at this critical period fre- quently have permanent mental retardation, which cannot be corrected by later ad- ministration of thyroid hormone or iodine. Most of the populations which live in areas of iodine deficiency are in developing countries, but many in the large indus- trialized countries of Europe are also affected (Delange 1994, Thyroid Disease in Adults 2011). 56 Knudsen and co-workers (2002) have demonstrated the risk factors for goiter and thyroid nodules. The major environmental factor that determines goiter prevalence is iodine status, but other environmental factors influencing entire populations have been identified such as goitrogens in food and drinking water (Knudsen et al. 2002). The environmental factors were also important for goiter development (increase in risk, smoking and pregnancy; decrease in risk, oral contraception and alcohol con- sumption), and the individual risk depended on the genetic background. Environ- mental factors also had only a minor influence on the prevalence of thyroid autoan- tibodies in the population (Laurberg et al. 2006). In iodine-deficient areas, a strong association between tobacco smoking and goiter prevalence is found, whereas the association is less pronounced in iodine-replete areas (Knudsen et al. 2002). The goiter prevalence is higher in certain groups in the population. The association with individual risk factors has been investigated in some studies, especially the associa- tion with tobacco smoking (Knudsen et al. 2002). Profound effects of even small dif- ferences in iodine intake level on the prevalence of goiter, nodules, and thyroid dys- function was demonstrated by Laurberg and co-workers (2006). The variation in goiter prevalence between the genders is well known with a higher occurrence among women. The association with age is probably dependent on iodine status, be- cause it seems that the zenith of goiter prevalence appears earlier in life the more se- vere iodine deficiency the population is exposed to (Knudsen et al. 2002). Mild and moderate iodine deficiency was associated with a decrease in serum thyroid- stimulating hormone (TSH) with age. There were more cases of overt hypothyroid- ism in mild than in moderate iodine deficiency caused by a 53% higher incidence of spontaneous (presumably autoimmune) hypothyroidism (Laurberg et al. 2006). On the other hand, there were 49% more cases of overt hyperthyroidism in the area with moderate iodine deficiency. Interestingly, the cautious iodine fortification program, aiming at an average increase in iodine intake of 50 μg/day has been associated with a 50% increase in incidence of hyperthyroidism in the area with the most severe io- dine deficiency. The incidence is expected to decrease in the future, but there may be more cases of Graves’ hyperthyroidism in young people (Laurberg et al. 2006). Ukraine has generally been an area of mild-to-moderate iodine deficiency (Gerasi- mov 2002). The following territories in Ukraine are biogeochemical provinces with io- dine deficiency: Zhitomir, Lviv, Ternopol, Volyn Oblast and other regions of Ukraine, and some regions of the Crimea as well. It is necessary that food rations be supple- mented with different iodine preparations with the view of preventing iodine deficiency (Gerasimov 2002). Preventative measures to eliminate iodine deficiency prior to 2001 had a negligible impact on the study population: only 5.4% of the population reported consuming iodinated preparations on an ongoing basis in the first round of screening (Aghini-Lombardi et al. 1999). Over the years 2001-2003, an improvement in iodine nutrition of the population was noted. There are epidemiologic studies in endemic goi- ter areas in Ukraine that report an increase in Hashimoto’s thyroiditis after the therapeu- tic administration of iodized salt (Tronko et al. 2005). Shiraishi and co-workers (2006) have estimated daily iodine intake in Ukrainian subjects of northwestern regions in relation to the health effects on inhabitants after the Chernobyl accident. Total diets were collected from 106 locations for children and adult males by a duplicate portion study. Iodine was rapidly determined by in- 57 ductively coupled plasma mass spectrometry after chemical separation. Iodine con- centration on a dry basis for Ukrainians was 0.11 µg and the daily iodine intake was in the range of 2.80-372 µg per person. The median, geometric mean, and standard deviation were 28.1, 32.7, and 2.51 µg, respectively. The yearly trend of the intake had almost no change. Regional differences would be expected to exist among the 10 areas of the