ESPE Abstracts

Background: Obesity has been defined as ‘abnormal or excessive fat accumulation that may impair health’ by World Health Organization.

Objective and hypotheses: Although the role of oxidative stress in obesity has been interest of subject in recent studies, comprehensive studies evaluating parameters of oxidant/antioxidant status in children are limited. Moreover, there has been an increasing focus on the relationship between obesity and thyroid function. This study was aimed to evaluate the role of oxidative stress in obesity and to investigate the possible relationship between thyroid hormones and oxidative stress parameters in obese children.

Method: The changes in oxidant/antioxidant status (lipid peroxidation (plasma MDA and urine F2 isoprostane); plasma carbonyl; erythrocyte antioxidant enzyme activities (glutathione peroxidase 1 (GP×1), superoxide dismutase (SOD), and catalase (CAT))) and thyroid hormone parameters (TSH and sT4) were measured in the newly diagnosed obese children (n=33, mean age=13.4).

Results: Indicate that the equilibrium between oxidants and antioxidants is deteriorated in obese children. SOD activity was found to be increased (33.7%; P<0.05) and CAT activity decreased significantly (12.8%; P<0.05) in obese children compared to control group (n=31; mean age=13.8). No changes were observed in GP×1 activity. Significant increases were found in carbonyl, MDA and F2-isoprostane levels of obese group when compared to control children. Significant alterations in thyroid hormone status were also detected in obese children. While levels of TSH elevated, levels of sT4 decreased significantly in obese children according to control (57 and 14% respectively).

Conclusion: 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. 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.