First-Trimester Circulating 25-Hydroxyvitamin D Levels and Development of Gestational

OBJECTIVE—To investigate the association between first-trimester maternal serum levels of 25-hydroxyvitamin D (25-OH-D) as measured by liquid chromatography-tandem mass spec-trometry and development of gestational diabetes mellitus (GDM). RESEARCH DESIGN ANDMETHODS—We conducted a case-control study involving 248 women in the first-trimester of pregnancy, 90 of whom developed GDM and 158 remained normoglycemic. RESULTS—Although booking 25-OH-D levels correlated negatively with 2-h glucose post-oral glucose tolerance test and positively with HDL cholesterol, as well as with ethnicity, obesity, and smoking (all P, 0.05), there were no statistically significant differences in baseline maternal mean 25-OH-D levels between those who subsequently developed GDM, 18.9 ng/mL (SD 10.7) and those who remained normoglycemic, 19.0 ng/mL (10.7) (P = 0.874), even after adjustment for possible confounders including sampling month (P = 0.784). CONCLUSIONS—Our large andwell-phenotyped prospective study did not find evidence of an association betweenfirst-trimestermaternal levels of 25-OH-D and subsequent development ofGDM. Diabetes Care 34:1091–1093, 201