The extreme of the environment in the North is determined not only by the harsh climatic conditions but also by a low diversity of nutrition with deficiency of vitamins and minerals necessary for the organism. A decrease of the bioelements in the body may lead to elementosis of mineral metabolism. One of these main diseases in Russia is endemic goiter typically associated with iodine deficiency. According to research, it is found that the southern areas of the Arkhangelsk region are the most iodine-deficient. A mild case of endemia was detected in the northern areas of the region which are located on the White Sea coast.
The spectrum of disorders in a child's development caused by iodine deficiency is rather wide. The iodine deficiency in children causes a decrease in immune reactivity, chronic diseases, neuropsychiatric and cognitive impairment. Insufficient intake of iodine leads to dysontogenesis of higher mental functions, formation of mental retardation of varying intensity in severe cases and in milder cases – borderline or partial intellectual disabilities. The dependence of the incidence of mental disorders on the factor of iodine deficiency is often explained by that iodine deficiency leads to a weakening of adaptability and stress resistance of the nervous system, reducing sensitive threshold to various psychosocial, genetic and exogenous organic factors.
The study aims to determine the influence of the goitre endemia level on morphofunctional and psychophysiological maturation of first-graders in the Arkhangelsk region.
The research involved first-graders of Arkhangelsk, Mezen, Onega and Pinega schools. The total amount of participants was 467 children, among them 230 girls and 237 boys.
Assessment of morphological maturity was carried out in terms of body length, school maturity, number of erupted permanent teeth and indicator of development options. Functional maturity was assessed using handgrip test and hemodynamics parameters. The "Method of assessing the level of development of visual perception of children 5-7.5 years " was used as the assessment of psychophysiological maturity. Toulouse-Pieron test that involves the assessment of psychophysiological maturity in terms of velocity and accuracy of psychomotor activity was also used.
To estimate the impact of iodine endemia on the biological maturity of children we conducted a correlation and factor analysis. The analysis of the structural correlation model of the system of biological maturity indicators in first-graders living in a mild level of goitre endemia allows to identify 3 system-forming complexes: morphological, dynamometric and hemodynamic. First-graders who live in the severe iodine endemic conditions are characterized by 2 system-forming complexes: morphological and dynamometric. It is not possible to distinguish the system-forming complexes in a group of children living in conditions of moderate iodine endemia.
Factor analysis carried out for indicators of biological maturity in groups of different goitre endemia degrees showed significant differences in the factor model of biological maturity. Indicators of biological maturity of children living in the mild goitre endemic conditions are grouped into 6 factors: the general factor includes indicators of dynamometry, factor 2 describes features of cardiovascular system development, other factors have different structure. Indicators of biological maturity of children living in the average goitre endemic conditions are grouped into 5 factors: general factor consists of indicators of cardiovascular system development, factor 2 illustrates morphological features of development, factors 3, 4, 5 have different structure. Indicators of biological maturity of children living in the severe goitre endemic conditions are grouped into 5 factors: general factor includes indicators of morphological development, factor 2 characterizes dynamometric indicators of development.
It was found that he goitre endemia level in the area of residence affects the rate of biological maturation of first-graders: children living in the area with mild goitre endemia are more mature in terms of most morphological and functional parameters.
Analysis of biological maturity of first-graders living in areas with diverse goitre endemia levels elucidated that the indicators of psychophysiological maturity to be less informative. That indicators do not constitute either a system-forming complex or a common factor in the system of biological maturity.
Comparison results of correlation and factor models of the biological maturity system indicate significant differences in the system of biological maturity of children living in different endemic conditions.