Endocrine Abstracts

Introduction: There is an increasing evidence of vitamin D role in maintaining normal glucose homeostasis. Gestational diabetes (GD) is related to insulin resistance and vitamin D deficiency has been linked with GD risk in some studies.

Aims: To assess whether vitamin D levels are related with gestational diabetes in a group of healthy pregnant women.

Subjects: The whole group included 845 pregnant women recruited from April 2009 to April 2010 initially selected to study vitamin D (25OHD) status. We also selected a subgroup (OGTT group) of 273 with abnormal O’Sullivan test who were performed an oral 100-g glucose tolerance test (OGTT) according to the American Diabetes Association (ADA) recommendations. Sixty-two of them were diagnosed of GD (GD+ group) and in 190 the OGTT was normal (GD− group). The 21 remaining didn’t complete the test.

Methods/measurements: 25OHD were measured at weeks 11–23 (D1) and 24–28 (D2) in the whole group and basal levels of glucose and insulin (minute 0 of the curve) in the OGTT group. Insulin resistance was calculated using the homeostasis model assessment (HOMA-IR) index. We compared 25OHD levels between GD+ and GD−. Pearson correlation analysis was used to test for univariate linear relationship between 25OHD and insulin, glucose and HOMA-IR.

Results: i) Median serum 25OHD concentration (ng/ml): weeks 11–13: DG+: 24.07 (6.07–39.70); DG−: 22.49 (4.53–55.56); (P=0.175); weeks 24–26: DG+: 23.2 (4.5–39.70); DG−: 25.60 (4–52.40); (P=0.27). ii) The relationship between 25OHD and glucose (r=0.12), insulin (r=0.047) and HOMA-IR (r=0.23) was not statistically significant.

Conclusions: i) Vitamin D levels were insufficient in both periods of pregnancy; ii) vitamin D levels were similar in women with and without gestational diabetes; iii) we didn’t find correlation between vitamin D levels and the parameters of glucose metabolism studied.