ARWA A ALAGEEL, RANA MOUTLAQ ALSAYALI, HUDA MOOFI ALHAJJAJ, FAHAD MOHAMMED SAMRAN ANAZI, MOROUJ SIDDIQ MAHDI, SAMA MOHAMMED ALNAFESSAH, RAGHAD ABDULRAQEB QARI ,RAGHAD AWAD, FATIMAH ABDULLAH ALHARBI, DALAL KHALID AL MASOUD, ARWA ABDULAZIZ ALAGEEL, FAISAL THAMER ALHUNAITI, AMMAR ABDULRAHMAN ALHARBI
DOI: https://doi.org/Background: Vitamin D deficiency has emerged as a potential modifiable risk factor in the pathogenesis of metabolic syndrome (MetS), a multifactorial condition characterized by insulin resistance, central obesity, hypertension, and dyslipidemia. Growing evidence suggests that low serum 25-hydroxyvitamin D [25(OH)D] concentrations may adversely affect glucose metabolism and insulin action.
Objectives: This systematic review aimed to evaluate the correlation between serum 25(OH)D levels and insulin sensitivity, as measured by HOMA-IR and related indices, among adults with MetS across diverse populations.
Methods: Following PRISMA 2020 guidelines, an extensive search of PubMed, Scopus, Web of Science, and Embase databases was conducted. Observational studies assessing the association between vitamin D status and insulin resistance in adults diagnosed with MetS were included. Data were extracted on study design, sample size, vitamin D assays, and insulin sensitivity measures.
Results: Eighteen studies met inclusion criteria, encompassing over 22,000 participants across North America, Asia, Europe, the Middle East, and Oceania. Serum 25(OH)D concentrations ranged from 15.8 to 67.1 nmol/L, with deficiency prevalence between 55% and 87%. Across studies, lower vitamin D levels consistently correlated with higher fasting insulin, glucose, and HOMA-IR values. Prospective evidence indicated that baseline vitamin D insufficiency predicted future declines in insulin sensitivity and increased MetS risk.
Conclusions: Findings demonstrate a consistent inverse relationship between serum vitamin D levels and insulin resistance in MetS populations, suggesting vitamin D deficiency as a plausible metabolic risk factor.
