25-Hydroxy vitamin D3 in patients with morbid obesity of wait-listed bariatric surgery: it’s association with adiposity and metabolic indices

Background and aim: Vitamin D3 deficiency is associated with insulin resistance and metabolic syndrome. Although, the evidence was not conclusive. The aim of this study is to investigate the relationship between serum 25-hydroxy vitamin D3 (25(OH) D3) levels with some adiposity and metabolic indices related to metabolic syndrome. Methods: In this cross-sectional study, the anthropometric, body composition information, the clinical laboratory tests including fasting blood sugar (FBS), insulin, lipid profile, liver enzymes, and serum 25(OH) D3 of 3750 patients with morbid obesity are extracted from Iran National Obesity Surgery Database. HOMA-IR and QUICKI were computed based on the standard formula. Associations were tested using analysis of variance and Kruskal–Wallis test. Results: Approximately 69% of patients with morbid obesity had sub-optimal vitamin D3 levels ( 20 ng/mL). An inverse significant relationship between serum 25(OH) D3 and body weight, body fat percentage, waist, and hip circumstance was observed (p 0.05 for all). Low serum 25(OH) D3 levels are significantly associated with higher FBS and A1C, dyslipidemia (higher LDL and TG), and also the elevated level of liver function enzymes (p 0.05 for all). Moreover, the patient with the higher serum 25(OH) D3 had a lower level of HOMA-IR and higher insulin sensitivity (QUICKI index); this association was not statistically significant, though. Conclusion: Vitamin D3 deficiency has been associated with adiposity, impaired glucose metabolism, and metabolic disorders related to insulin resistance. Thus, vitamin D3 supplementation could be a potential approach in treatment or decrease of the metabolic complication of obesity before and after bariatric surgery