Breath Mass Spectrometry in Metabolic Syndrome and Metabolically Healthy Obesity

Inclusion Criteria: * For Group 1 (Metabolic syndrome): Age \>18 years, signed informed consent, diagnosis of Metabolic Syndrome (IDF 2006 criteria: waist circumference \>94 cm (men)/ \>80 cm (women) + ≥2 of: BP ≥130/85 mmHg or antihypertensive therapy; TG ≥1.7 mmol/L; HDL-C \<1.03 mmol/L (men) / \<1.29 mmol/L (women); Fasting glucose ≥5.6 mmol/L). * For Group 2 (Metabolically healthy obesity): Age \>18 years, signed informed consent, waist circumference ≥94 cm (men) / ≥80 cm (women), absence of other Metabolic Syndrome criteria (hypertension, dyslipidemia, impaired fasting glucose). * For Group 3 (Control): Age \>18 years, signed informed consent, normal BMI, absence of signs of Metabolic Syndrome. Non-inclusion criteria for all groups: * Inability to provide informed consent; * History of myocardial infarction or stroke; * Chronic kidney disease stage 3B, 4, 5 (eGFR \<30 ml/min/1.73m2); * Acute or subacute cardiovascular disease; * Familial hypercholesterolemia; * Bronchopulmonary diseases; * Acute or chronic infectious diseases; * Type 1 or Type 2 diabetes mellitus; * Systemic connective tissue diseases; * Current or past history of oncological diseases; * Severe liver dysfunction, decompensated liver cirrhosis (Child-Pugh class C); * Pregnancy or lactation; * Severe mental illness (severe dementia, schizophrenia); * Comorbid conditions with life expectancy less than 1 year. Exclusion Criteria: * Patient refusal to continue participation in the study; * Identification of any non-inclusion criteria after enrollment.