title: First-trimester maternal vitamin D status and risk for gestational diabetes (GDM) a nested case-control study.
abstract: BACKGROUND
  Vitamin D deficiency may contribute to impaired glucose metabolism. There are sparse data regarding vitamin D and the development of gestational diabetes (GDM). The objective of this study was to assess if first-trimester vitamin D deficiency is more prevalent in women later diagnosed with GDM compared with women with uncomplicated pregnancies.
  
  
  METHODS
  We conducted a nested case-control study of pregnant women who had previously given blood for routine genetic multiple marker screening and subsequently delivered at a tertiary hospital between November 2004 and July 2009. From an overall cohort of 4225 women, 60 cases of GDM were matched by race/ethnicity with 120 women delivering at term (≥37 weeks) with uncomplicated pregnancies. Banked maternal serum was used to measure maternal 25-hydroxyvitamin D [25(OH)D].
  
  
  RESULTS
  The prevalence of first-trimester maternal vitamin D deficiency (defined as 25(OH)D < 50 nmol/L) was comparable among women with GDM compared with controls (5/60 vs 8/120, p = 0.90). The median 25(OH)D level for all subjects was 89 nmol/L (interquartile range, 73-106 nmol/L). Seventy three percent (117/160) of the cohort had 25(OH)D levels ≥75 nmol/L.
  
  
  CONCLUSIONS
  In a cohort of pregnant women with mostly sufficient levels of serum 25(OH)D, vitamin D deficiency was not associated with GDM. Further studies are warranted with larger cohorts, especially in populations with lower levels of vitamin D.
authors.affiliation: Memorial Health University Medical Center, Mercer School of Medicine, Savannah Campus, Savannah, GA 31404, USA. arthurbaker@memorialhealth.com
authors.forename: Arthur M
authors.initials: AM
authors.lastname: Baker
authors.forename: Sina
authors.initials: S
authors.lastname: Haeri
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
authors.forename: Alison M
authors.initials: AM
authors.lastname: Stuebe
authors.forename: Kim A
authors.initials: KA
authors.lastname: Boggess
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D016640:Diabetes, Gestational / Q000209:etiology*; D005260:Female; D006801:Humans; D009657:North Carolina / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood; D011261:Pregnancy Trimester, First; D015995:Prevalence; D012306:Risk; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications* / Q000453:epidemiology
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D