Endocrine Abstracts

Objetive: Obesity is associated with lower serum vitamin D (25(OH)D₃) levels through several mechanisms. The aim of the study was to determine the prevalence of vitamin D deficiency and to examine the association between insulin resistance and 25(OH)D₃ levels in a cohort of obese subjects.

Materials and methods: 85 obese subjects were enrolled into the study from october to december 2018. Demographic, anthropometric and clinical parameters were assessed. Serum fasting levels of 25(OH)D₃, insulin, glucose, uric acid and lipids (triglycerides, total, HDL and LDL cholesterol) were measured. Insulin resistance was assessed by using the homeostasis model assessment (HOMA2-IR, HOMA2-%S and HOMA2-%B). Vitamin D deficiency was defined by levels of 25OHD₃ <10 ng/ml.

Results: 85 obese subjects (58 women and 27 men), mean age 43.8±14.5 years. BMI 43.6±8.2 Kg/m², SBP 133.4±18.7 mmHg, DBP 84.6±11.1 mmHg, fasting glucose 100.8±30.6 mg/dl, HbA1c 6.01±1.05%, total cholesterol 18.4±33.8 mg/dl, HDL-c 47.8±10.4 mg/dl, LDL-c 111.5±28.2 mg/dl, triglycerides 152.8±84.8 mg/dl, 25OHD₃ 17.5±6.01 ngl/ml. Vitamin D deficiency was present in 5.88% of subjects. 25(OH)D₃ levels were significantly and negatively correlated with HOMA2-% B (P=0.07) and serum insulin (P=0.09). 25(OH)D₃ levels were also reported to be directly related to HOMA2-% S (P=0.01).

Conclusion: We found an association between vitamin D and hyperinsulinemia. These results suggest that serum vitamin D deficiency could be an insulin resistance marker.