Clinically silent adrenal incidentalomas: their relation to metabolic syndrome and to GNB3 C825T gene polymorphism
Ivica Lazúrová, Daniela Spišáková, Hedviga Wagnerová, Viera Habalova, Ingrid Dravecká, Darina Petrášová & Lýdia Pundová
Objectives: Aim of the study was firstly to assess the prevalence of metabolic symptoms in patients with clinically silent and benign adrenal incidentalomas (AI) and secondly to determine the prevalence of C825T GNB3 gene polymorphism in AI as well as its relation to metabolic variables.
Subject and methods: Group of patients consisted of 50 patients with AI of mean age 57.9±15 years and group of controls consisted of 22 subjects without AI and metabolic disorders (mean age 53.5±4.2 years). Prevalence of insulin resistance calculated as HOMA index was significantly higher in AI than controls (38 vs 9%) as was the prevalence of overweight or obesity (78 vs 45%).
Results: Patients with AI had signifcantly higher BMI, HOMA, triacylglycerols (P<0.05) and significantly lower serum adiponectine (P<0.05) than controls. There were no significant differences in metabolic parameters between group with and without subclinical Cushing syndrome (SCS). There was no relation of metabolic parameters to the size of the tumor although patients with tumor larger than 3 cm had significantly higher serum cortisol after dexamethasone. The prevalence of T allele of GNB3 gene was not significantly higher than the prevalence of C allele (32 vs 47%). However carriers of T allele had significantly lower serum adiponectin than those with C allele only (P<0.01).
Conclusion: We conclude that patients with AI have significantly higher cardiovascular risk factors that are not related to the presence of SCS. Moreover patients with AI and with TC or TT genotype have significantly lower serum adiponectin which may be an early symptom of metabolic synrdrome in patients with AI.