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.