Dissertation committee:
Ευαγγελία Χαρμανδάρη, Καθηγήτρια, Ιατρική Σχολή, ΕΚΠΑ
Γεώργιος Χρούσος, Ομότιμος Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Ιωάννης Μανιός, Καθηγητής, Σχολή Επιστημών Υγείας και Αγωγής, Χαροκόπειο Πανεπιστήμιο
Γεώργιος Μαστοράκος, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Κωνσταντίνος Τσίγκος, Καθηγητής, Χαροκόπειο Πανεπιστήμιο
Φλώρα Μπακοπούλου, Αναπληρώτρια Καθηγήτρια, Ιατρική Σχολή, ΕΚΠΑ
Ιωάννης Κύρου, Επίκουρος Καθηγητής, Τμήμα Επιστήμης Τροφίμων και Διατροφής του Ανθρώπου, Γεωπονικό Πανεπιστήμιο Αθηνών
Summary:
Background: Overweight and obesity in childhood and adolescence represent a major public health problem of our century, and account for increased morbidity and mortality in adult life. irisin and Fibroblast Growth Factor-21 (FGF-21) have been proposed as prognostic and/or diagnostic biomarkers in subjects with obesity and metabolic syndrome, because they increase earlier than other traditional biomarkers.
Objective and Hypotheses: We determined the concentrations of irisin and FGF-21 in children and adolescents with overweight and obesity before and after one year of a life-style intervention program of diet and physical exercise and explored the impact of body mass index (BMI) reduction on the concentrations of irisin, FGF-21 and other cardiometabolic risk factors.
Patients and Methods: Three hundred and ten (n = 310) children and adolescents (mean age ± SD: 10.5 ± 2.9 years; 162 males, 148 females; 152 prepubertal, 158 pubertal), attending our Out-patient Clinic for the Prevention and Management of Overweight and Obesity in Childhood and Adolescence, "Aghia Sophia" Children’s Hospital, Athens, Greece, were studied prospectively for 1 year. Subjects were classified as having obesity (n = 211, 68%), or overweight (n = 99, 32%), according to the International Obesity Task Force (IOTF) criteria. Inclusion criteria were age 2–18 years old and increased BMI for age and gender. All subjects were evaluated and entered an intervention program that provided personalized advice and guidance on diet and physical exercise to patients and their families, by a multidisciplinary team. Subjects with obesity were followed-up every month and subjects with overweight every two months. Αt the begging and the end of the study clinical evaluation, body fat measurements and hematologic, biochemical, and endocrinologic investigations were performed. Irisin and FGF-21 concentrations were determined using a commercially available enzyme-linked immunoassay (ELISA) kit. The study was approved by the Ethics Committee and written informed consent was obtained by all parents or guardians of the participants.
Results: Following one year of the life-style intervention program, there was a significant decrease in BMI (p = 0.001), waist-to-hip ratio (WHR) (p = 0.024), waist-to-height ratio (p = 0.024), total cholesterol (p = 0.001), LDL (p = 0.001), Apolipoprotein-B concentrations (p = 0.001), fat mass (p = 0.001) and irisin concentrations (p = 0.001), and an increase in muscle mass (p = 0.001), free-fat mass (p = 0.001) and HDL (p = 0.001). FGF-21 concentrations correlated positively with BMI (p = 0.001), waist circumference (p = 0.001), triglycerides (p = 0.001), HOMA-IR (p = 0.001), fat mass percentage (p = 0.043), muscle mass (p = 0.002) and bone mass (p = 0.003). Multivariate linear regression analysis indicated that the change in WHR was the only independent variable affecting irisin change (β = -465.55 (95% CI: -918.40 to 12.70), p = 0.044).
Conclusions: The above findings indicate that the decrease in BMI in children and adolescents with overweight or obesity following one year of implementation of a personalized, multi-disciplinary, life-style intervention program of diet and exercise resulted in a significant reduction in irisin concentrations, as well as an improvement in cardiometabolic risk factors. Further studies are required to determine the potential role of irisin as a biomarker for monitoring the response to lifestyle interventions and for predicting the development of cardiometabolic risk factors.
Keywords:
Irisin, FGF-21, Fibroblast growth factor-21, Overweight, Obesity, Childhood, Adolescence
