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78Adequate and timely thyroid function is necessaryfor physical and intellectual development.Damage to the thyroid gland of thefetus or the neonate may doom that individualto a life of diminished mental capacity.In pregnant women, synthesis of cortisol, anadrenal hormone, and testosterone correlatedwith the level of internal irradiation (Duda andKharkevich, 1996). Children in the contaminatedterritories had significantly lower cortisolblood levels (Petrenko et al., 1993). Measurementsof immunity in children and teenagerswith Hashimoto autoimmune thyroiditis correlatedwith the level of environmental radioactivecontamination (Kuchinskaya, 2001).Review of many similar examples clearlyshows that Chernobyl radiation dangerouslyimpacted the endocrine system. But what isthe scale of such impacts? Concrete examplesare presented in this section to answer some ofthese questions. After a brief review of materialabout endocrine system diseases (Section 5.3.1),we deal with the central problem of endocrineillnesses linked to the Chernobyl catastrophe—functional impairment of the thyroid gland(Section 5.3.2).5.3.1. Review of Endocrine SystemDisease DataEndocrine system diseases are widespreadin all of the territories that were exposedto the Chernobyl radioactive fallout (Balevaet al., 1996; and many others). Compared withdata from normal people, individuals living inthe contaminated territories have 50% lowersympathetic activity and 36% lower adrenalcortical activity. In 28% of surveyed newbornsin contaminated areas, disorders in thehypophyseal–thyroid system, expressed as thyroiddysfunction, during the end of the firstand the beginning of the second week of lifeultimately resulted in hypothyroidism with itsattendant mental and physiological abnormalities(Kulakov et al., 1997).5.3.1.1. Belarus1. A sharp increase in endocrine diseases inall Belarussian contaminated territories was observedsome years after the catastrophe (Lomat’et al., 1996; Leonova and Astakhova, 1998; andmany others). According to the State Register,in 1994 endocrine system morbidity reached4,851 per 100,000 (Antypova et al., 1995).2. Children from heavily contaminated territorieshad blood cortisol levels that were significantlylower than the norm. Cortisol isan adrenal hormone that is released understress (Petrenko et al., 1993). In Gomel andMogilev provinces, the levels of umbilical bloodcortisol and estriol in areas having Cs-137contamination of less than 1–15 Ci/km 2 weresignificantly higher than the level from heavilycontaminated territories (15–40 Ci/km 2 ;Danil’chik et al., 1996). Overtly healthy newbornsin Gomel and Mogilev provinces had elevatedcortisol levels where contamination wasless than 15 Ci/km 2 and decreased levels inheavily contaminated areas (Danil’chik et al.,1996). The number of children with impairedhormone secretion (cortisol, thyroxin, and progesterone)was significantly higher in heavilycontaminated territories (Sharapov, 2001).3. Children from heavily contaminated territorieshad lower levels of testosterone, a hormoneassociated with physical development,with low levels linked to impaired reproductivefunction (Lyalykov et al., 1993).4. Many girls of pubertal age, 13 to 14years, from the contaminated territories withautoimmune thyroiditis had accelerated sexualdevelopment with significantly increasedblood serum concentrations of gonadotropichormones in the lutein phase of their menstrualcycles (Leonova, 2001).5. Children aged 10 to 14 years born to irradiatedparents diagnosed from 1993 to 2003showed significantly more morbidity from goiterand thyroiditis (National Belarussian Report,2006).6. In some areas where congenital diabeteshad not been seen at all before the catastrophe,