Metabolic Obesity in Normal Weight (MONW): Diagnostic Markers Stud

Study Design and Population:

This is a longitudinal observational study involving 176 healthy women aged 18-35 years. The primary aim is to identify diagnostic markers for Metabolically Obese Normal Weight (MONW) individuals. Recruitment is conducted via digital prescreening and university networks. Eligible participants must have a normal BMI (18.5-24.9 kg/m²) and stable body weight.

Group Allocation:

Participants will be divided into two groups based on Body Fat Percentage (PBF) assessed by Dual-Energy X-ray Absorptiometry (DXA):

• MONW Group: BMI < 25 kg/m² and PBF ≥ 35.78% (threshold derived from pilot population studies).
• Control Group: BMI < 25 kg/m² and PBF < 35.78%.

Study Procedures:

The study involves a baseline visit and a follow-up visit after 12 months.

• Standardization: Visits are scheduled during the early follicular phase of the menstrual cycle (days 3-7) to minimize hormonal variability affecting endothelial function. Participants must fast for at least 12 hours and abstain from caffeine, smoking, and strenuous exercise for 24 hours prior.
• Anthropometry and Body Composition: Height, weight, and circumferences (waist, hip) are measured. Whole-body composition is analyzed using DXA (Hologic QDR 4500W) to determine total and visceral fat mass.
• Endothelial Function Assessment (FMD): Flow-mediated dilation of the brachial artery is measured using high-resolution ultrasound (Alpinion Xcube 90, linear probe L3-12). The protocol includes:

• 1-minute baseline imaging.
• 5-minute occlusion (cuff inflation to 250 mmHg).
• 3-minute continuous post-occlusion imaging to assess peak diameter.
• Biochemical Analysis: Fasting blood samples are collected for:

• Lipid profile (TC, LDL, HDL, TG) and glucose metabolism markers (glucose, insulin, HbA1c).
• ELISA quantification of specific biomarkers: Asprosin, Asymmetric Dimethylarginine (ADMA), von Willebrand Factor (vWF), and sex hormones (Estradiol, Testosterone, SHBG).
• Metabolomics: Targeted and untargeted metabolomic profiling (LC-MS/MS) is performed on a subset of plasma samples to identify metabolic signatures associated with the MONW phenotype.

Data Collection:

Participants also complete standardized questionnaires regarding physical activity (IPAQ) and dietary habits (62-item FFQ-6, KomPAN). All data is pseudonymized and stored on a secured server.

Inclusion criteria

• Written, informed consent to participate in the research.
• Gender: Female.
• Age 18-35 years.
• BMI in the range of 18.5-25 kg/m².

Exclusion criteria

• Thyroid disease.
• Pregnancy or breastfeeding.
• Eating disorders.
• Polycystic ovary syndrome (PCOS).
• Hormone therapy and/or use of hormonal contraceptives.
• Smoking.
• Metal or silicone implants (contraindication for DXA/body composition accuracy).
• Vitamin and/or mineral supplementation.
• Acute and/or chronic illnesses.
• Type I or II diabetes, dyslipidemia, hypertension.
• Use of hypolipemic, antihypertensive, antiglycemic, or insulin medications.