This prospective cross-sectional case-control study aims to investigate the relationship between serum vitamin D levels, visceral adipose tissue (VAT) thickness, and metabolic parameters in adolescents diagnosed with polycystic ovary syndrome (PCOS), compared to healthy controls. The study includes 70 adolescents with PCOS and 40 age-matched healthy adolescents, all aged between 12 and 19 years, who attended the adolescent gynecology outpatient clinic of a tertiary care hospital. Serum 25-hydroxy vitamin D [25(OH)D] levels, fasting glucose, fasting insulin, lipid profiles, anthropometric measurements, and ultrasound-based VAT thickness were assessed. The study seeks to explore potential associations between vitamin D deficiency and metabolic dysregulation in adolescent PCOS patients and to better understand the early cardiometabolic risks associated with PCOS during adolescence.

Polycystic ovary syndrome (PCOS) is a common endocrine disorder affecting women of reproductive age, with manifestations often beginning during adolescence. It is associated not only with reproductive abnormalities but also with significant metabolic complications, including insulin resistance, obesity, dyslipidemia, and an increased risk of metabolic syndrome. Recent evidence suggests that vitamin D deficiency may play a role in the metabolic dysfunction observed in PCOS, although the exact mechanisms remain under investigation.

This prospective cross-sectional case-control study aims to evaluate the relationship between serum 25-hydroxy vitamin D [25(OH)D] levels, visceral adipose tissue (VAT) thickness, and metabolic parameters in adolescents with PCOS compared to healthy controls. The study population includes 70 adolescents diagnosed with PCOS according to the NIH criteria and 40 age-matched healthy adolescents, all aged between 12 and 19 years, attending a tertiary care hospital's adolescent gynecology clinic.

Participants underwent detailed clinical and anthropometric assessments, including measurements of body mass index (BMI), waist circumference, hip circumference, and waist-to-hip ratio (WHR). Biochemical evaluations included fasting plasma glucose, fasting insulin, lipid profiles, and serum 25(OH)D levels. Insulin resistance was assessed using the HOMA-IR .

VAT and subcutaneous adipose tissue (SAT) thickness were measured by transabdominal ultrasound, utilizing a standardized technique for consistency. All ultrasound measurements were performed by the same experienced investigator to ensure reliability, and intraobserver agreement was assessed.

The primary objective of the study is to investigate potential associations between vitamin D deficiency and metabolic disturbances in adolescents with PCOS, focusing particularly on insulin resistance, lipid abnormalities, and visceral fat accumulation. The findings may contribute to a better understanding of early cardiometabolic risk in adolescents with PCOS and help in developing targeted preventive strategies.

Inclusion Criteria:

• Female adolescents aged 13 to 19 years
• Having attained menarche at least two years prior to enrollment
• For PCOS group: Diagnosis of polycystic ovary syndrome based on NIH criteria (presence of menstrual irregularity and clinical and/or biochemical hyperandrogenism)
• For Control group: Regular menstrual cycles (cycle interval 21-35 days) and no clinical or biochemical signs of hyperandrogenism.

Exclusion Criteria:

• Use of medications affecting vitamin D metabolism, insulin sensitivity, or androgen levels within the past 6 months (e.g., oral contraceptives, insulin sensitizers, vitamin D supplements)
• Presence of endocrine disorders such as congenital adrenal hyperplasia, hyperprolactinemia, Cushing's syndrome, thyroid dysfunction.
• Chronic systemic diseases (e.g., diabetes mellitus, severe liver or kidney disease).

Female adolescents aged 13 to 19 years who attended the adolescent gynecology outpatient clinic of a tertiary care hospital. Participants included adolescents diagnosed with polycystic ovary syndrome based on NIH criteria and age-matched healthy controls. All participants had attained menarche at least two years prior to enrollment.