title: Early pregnancy maternal vitamin D concentrations and risk of gestational diabetes mellitus.
abstract: BACKGROUND
  While associations of vitamin D deficiency with type 2 diabetes have been well demonstrated, investigations of vitamin D and risk of gestational diabetes mellitus (GDM) reported inconsistent findings. We examined associations of vitamin D status with GDM.
  
  
  METHODS
  In a nested case-cohort study (135 GDM cases and 517 non-GDM controls), we measured maternal serum vitamin D status (total 25[OH]D and 25[OH]D3 ) in early pregnancy (16 weeks on average) using liquid chromatography-tandem mass spectroscopy. GDM was diagnosed according to the American Diabetes Association guidelines. We calculated adjusted odds ratios and 95% confidence intervals (CIs) using logistic regression models.
  
  
  RESULTS
  GDM cases had lower mean total 25[OH]D (27.3 vs. 29.3 ng/mL) and 25[OH]D3 (23.9 vs. 26.7 ng/mL) concentrations compared with women who did not develop GDM (both P-values < 0.05). Overall, 25[OH]D3 concentrations, but not total 25[OH]D concentrations, were significantly associated with GDM risk. A 5-ng/mL increase in 25[OH]D3 concentration was associated with a 14% decrease in GDM risk (P-value = 0.02). Women in the lowest quartile for 25[OH]D3 concentration had a twofold [95% CI 1.15, 3.58] higher risk of GDM compared with women in the highest quartile (P-value for trend < 0.05).
  
  
  CONCLUSIONS
  Early pregnancy vitamin D status, particularly 25[OH]D3 , is inversely associated with GDM risk.
authors: Department of Epidemiology, University of Washington School of Public Health and Community Medicine, Seattle, WA; Center for Perinatal Studies, Swedish Medical Center, Seattle, WA; Evaluation and Research, Louisiana Public Health Institute, New Orleans, LA.
authors: Dodie L
authors: DL
authors: Arnold
authors: Daniel A
authors: DA
authors: Enquobahrie
authors: Chungfang
authors: C
authors: Qiu
authors: Jonathan
authors: J
authors: Huang
authors: Nancy
authors: N
authors: Grote
authors: Ann
authors: A
authors: VanderStoep
authors: Michelle A
authors: MA
authors: Williams
mesh_terms: D016640:Diabetes, Gestational / Q000188:drug therapy / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D006801:Humans; D011247:Pregnancy; D037841:Pregnant People; D011446:Prospective Studies; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood* / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications* / Q000188:drug therapy*; D014815:Vitamins / Q000097:blood / Q000627:therapeutic use*
chemical_list: D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: case-cohort study; gestational diabetes; pregnancy; vitamin D