Endocrine Abstracts

Objective: To assess glucose metabolism (GM) parameters before and after vitamin D treatment in pre-diabetic women.

Material and Methods: In the study were included fifty eight women with prediabetes (impaired fasting glucose (IFG) or impaired glucose tolerance (IGT)) aged from 40 to 55 with signed informed consent. The study didn’t include women with diseases affecting the vitamin D metabolism, as well as women receiving regular vitamin D supplementation. All included women were randomized to two groups: to receive 4,000 IU (group 1, n = 30) and 500 IU (group 2, n = 28) cholecalciferol daily for 3 months. At the beginning of the study groups were comparable at age, BMI, HbA1c level. At the baseline and at the end of the study were determined the levels of 25(OH)D and GM parameters including HbA1c, glucose, insulin during OGTT (0, 60, 120 min).

Results: Baseline serum 25(OH)D level was 19.9 ± 8.8 ng/ml, 87.9% of women were insufficient 21 (36.2%) or deficient 30 (51.7%): 28 (93.3%) ingroup 1 and 23 (82.2%) in thegroup 2. After 3 months serum 25(OH)D level increased in all patients (mean 34.3 ± 14.5 ng/ml), however, normalization was detected only in group 1–40.4 ± 14.8 ng/ml. An analysis of GM parameters revealed a decrease in plasma glucose levels at 60’ (P = 0.04) and 120’ (P = 0.04), and reduction in HbA1c level of 6.8% (5,9 ± 0.2% → 5.5 ± 0.2) (P = 0.001) in women who received 4,000 IU/day. Also, cholecalciferol treatment did not lead to a significant change in fasting insulin level, but was accompanied by an increase in insulin level at 120’ by 28.8% (66.7 ± 63.7 → 85.9 ± 3.5) (P = 0.03) after three months only in group 1. Type 2 diabetes was diagnosed in three (10.7%) women in group 2, while 50% of women had normal glucose level and HbA1c in the group 1 (P = 0.001).

Conclusion: A dose of 4,000 IU cholecalciferol over three months is associated with a normalization of 25(OH) D level and improved glucose metabolism parameters in pre-diabetic vitamin D insufficient women.