Association of Vitamin D Status With Metabolic Markers in Adolescents With Polycystic Ovary Syndrome

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).