Maternal 25 hydroxyvitamin D level and its correlation in Thai gestational diabetes patients.

OBJECTIVE To identify 25 hydroxyvitamin D (250HD) levels in Thai pregnant women with gestational diabetes and nongestational diabetes. MATERIAL AND METHOD This prospective study was conducted on 197 pregnant women at Rajavithi Hospital, a tertiary care medical center in Bangkok from October 2010 to July 2011. Plasma 25 hydroxyvitamin D concentration and HbA1c level during the 75 g OGTT in gestational diabetes mellitus (GDM) and non-GDM were evaluated. The recommendations of the International Association of Diabetes and Pregnancy Study Groups (IADPSG) were used for diagnosis of GDM in the present study. RESULTS In the selected 197 Thai pregnant women aged from 18 to 49 years, the mean age was 32.1 years, and the mean plasma 250OHD level was 34.3 ng/dl. The percentages of patients classified as having 25OHD deficiency (< 20 ng/dl), 25OHD insufficiency and normal 25OHD were 3.1%, 22.3% and 74.6%, respectively. Among the 197 women, 70 patients (34.8%) had GDM. In the GDM group, 29 patients (41.4%) had abnormal 25OHD level of which 5.7% had 25OHD deficiency and 35.7% had 25OHD insufficiency. Among those with GDM, plasma 25OHD concentration was significantly lower than in the non-GDM subjects (32.3 +/- 10.3 vs. 35.5 +/- 6.7 ng/dl, p = 0.001). Fasting blood glucose and HbA1C independently predicted low 25OHD levels in Thai GDM subjects after applying regression model and adjusting for age, BMI, trimester and family history of DM (p = 0.031, p = 0.014 respectively). Higher pre-pregnancy BMI was associated with GDM and lower 25OHD level. CONCLUSION Thai pregnant women with GDM had lower levels of 25OHD compared to those without GDM. Only fasting plasma glucose independently predicted low 25OHD levels in GDM subjects.