[Peculiarities of disorders in physical development of children consuming drinking water with increased nitrate...

Peculiarities of physical development disorders in 334 children were examined in the course of comparative clinical-laboratory research; all these children consumed drinking water with various nitrates content (11.2±1.1 mg/l and up to 3.14 MPC, i.e. 141 mg/l), in a dose equal up to 9.0 mg/kg of body weight (RfD 1.6 mg/kg). A focus group consisted of 158 children aged from 3 to 10, a control group was made up of 176 children of the same age. Nitrates content in urine taken from children of focus group (49.22±11.69 mg/l) was 2.4 fold higher than the same parameter in control group (20.2±3.13 mg/l, р=0,001). Under exposure to nitrates consumed with drinking water endocrine system diseases were detected 1.7-2.1 fold more frequently, and physical development disorders, 2.5-4.3 fold more frequently, than in control group (р=0.02-0.05). We detected authentic correlation between nitrate excretion with urine and deviations in physical development in children consuming drinking water with nitrogenous compounds content which was higher than MPC; such deviations were ICD: Е44-Е46 - mild protein-energy malnutrition, Е34.4 - excessive height, Е67.8-Е66.0 - excessive nutrition, ОR=2.35, DI=1.22-4.53). Explained variance fraction amounted to 42-75% (R2=0.42-0.75; 64.9≤F≤162.3, р=0.001). Changes in thyroid gland volume were detected 2.4 fold more frequently, and changes in its structure 2.5 fold more frequently, in focus group than in control group (р=0.049). We determined statistically significant correlation between thyroidal disorders and nitrate content in urine (ОR=3.52; DI=1.73-7,0), with factor contribution level reaching 52% (R2=0.52; F=173.3; р=0.001). We detected that 34% of children from focus group had thyrotrophic hormone level 1.2 fold higher than physiological standard and the same parameter in control group (р=0.02). And also free thyroxin level was near age physiological standard in 23.4% of examined children which was 1.2 fold lower than in control group (p=0.05). The research revealed that methemoglobinemia with tissue respiration abnormalities and disorders in liver enzyme system functioning followed by protein-energy malnutrition (ICD: E44.1-E46), were the most relevant for younger children (under 6 years) and children suffering from functional gastrointestinal pathologies. As for older children (6-10 years) we observed mostly disorders in neuroendocrine regulation, thyroid gland, and antioxidant protection, in them together with somatic development potentiation and growth in weight-height parameters (ICD: Е66.0-Е67.8). It has been established that reduced thyroid supply, disorder of tissue respiration and antioxidant balance, and dysregulation of hypophysial-adrenal homeostasis section provide the basis for the formation of disturbances in physical development and endocrine pathology in children being under oral exposure to nitrates.