Obez Çocuklarda Tiroid Işlev Bozuklukları ve Oksidan Antioksidan Statü Arasındaki Ilişkinin Metabolik Risk Etmenleri ile Birlikte Değerlendirilmesi.

Abstract

Obesity has been defined as “abnormal or excessive fat accumulation that may impair health” by World Health Organization. Obesity is a chronic illness the prevalence of which has increased in both developed and developing countries, affecting gradually children as well as adults. The prevalence of obesity has been increasing in all age groups. The studies performed on adults indicate that oxidative stress may play an important role in the pathogenesis of obesity-related complications, such as type 2 diabetes mellitus and cardiovascular diseases. The role of oxidative stress in childhood obesity have been interest of subject in recent studies. However, in children, comprehensive studies evaluating parameters of oxidant/antioxidant status are limited compared to adults. On the other hand, particularly in recent years, the relation between obesity and thyroid disorders have been attracting substantial attention. This thesis was planned in the enlightenment of these data and changes in oxidant/ antioxidant status (plasma MDA and urine F2 isoprostane levels; plasma carbonyl and thiol levels; erythrocyte antioxidant enzyme activities including glutathione peroxidase 1 [GPx1], superoxide dismutase [SOD], catalase [CAT])) and thyroid hormone parameters (TSH, sT4) were measured in the newly diagnosed obese children who were divided into two groups as “high metabolic risk carriers and “low metabolic risk carriers” concerning their metabolic risk factors [lipid profile (HDL, LDL, cholesterol, triglyceride), glucose metabolism (fasting blood sugar and insulin), systolic and diastolic blood pressure. The results indicate that the equilibrium between oxidants and antioxidants is deteriorated in obese children, particularly in high metabolic risk carriers. The significant correlations between lipid peroxidation and CAT activity and in lipid and glucose profiles particularly accentuate the relationship between oxidative stress and metabolic risk factors. Important alterations in thyroid hormone status were also detected in obese children. These alterations might occur as an adaptive response to increase the energy expenditure in obesity or the oxidative stress observed in obesity might be a possible underlying mechanism in the disruption of thyroidal functions. Besides, significant correlations were determined indicating that the changes in thyroid hormone parameters may further contribute to the alterations in metabolic risk factors, namely lipid and glucose profiles and blood pressure. The findings that contribute to the definition of pathophysiology of childhood obesity may have marked importance in preventing cardiovascular diseases that might arise in older ages and in developing preventive approaches.