The Relationship between Vitamin D Levels and Blood Glucose and Cholesterol Levels

Background: Vitamin D deficiency has reached epidemic proportions globally. Observational data link low vitamin D status to diabetes, dyslipidemia, and metabolic syndrome, but interventional trials on the effects of supplementation are limited. Objective: We investigated associations between serum 25-hydroxyvitamin D (25(OH)D) levels and metabolic markers in Saudi adults. Methods: This retrospective cross-sectional study analyzed the clinical records of 476 patients from Saudi Arabia, aged 15–78 years. According to 25(OH)D levels, participants were stratified as vitamin D-sufficient (≥30 ng/mL), -insufficient (21–29 ng/mL), or -deficient (≤20 ng/mL). The outcomes were diabetic status (fasting glucose, HbA1c) and lipid panel results. Results: Higher diabetes prevalence was significantly associated with lower 25(OH)D levels (10.1% in the sufficient group, 11.6% in the insufficient group, and 18.3% in the deficient group). Similarly, worse lipid profiles were associated with more severe hypovitaminosis D, including a total cholesterol level of ≥240 mg/dL (5.3% in participants with normal vitamin D levels vs. 18.9% in those with deficient levels) and LDL ≥ 160 mg/dL (6.9% in participants with normal vitamin D levels vs. 13.2% in those with deficient levels). Vitamin D deficiency disproportionately affected women and adults > 45 years old. Conclusions: Vitamin D deficiency is endemic in Saudi Arabia and strongly linked to worsened metabolic markers. Optimizing vitamin D status through screening and correcting the deficiency may provide a cost-effective approach to confronting the regional diabetes epidemic and reducing cardiovascular disease risk.