title: Determinants of mild gestational hyperglycemia and gestational diabetes mellitus in a large dutch multiethnic cohort.
abstract: OBJECTIVE
  The purpose of this study was to identify independent determinants of mild gestational hyperglycemia (MGH) and gestational diabetes mellitus (GDM) and to assess the correlation between fasting glucose and C-peptide levels among control, MGH, and GDM women.
  
  
  METHODS
  A total of 1,022 consecutive women were evaluated with a 1-h 50-g glucose challenge test (GCT) at between 16 and 33 weeks of gestation. Women with a capillary whole-blood glucose > or =7.8 mmol/l in the GCT underwent a 3-h 100-g oral glucose tolerance test (OGTT). On the basis of a positive GCT, the women with a positive OGTT were classified as GDM, whereas the women with a negative OGTT were classified as MGH. The following data were collected for all women: age, prepregnancy BMI, ethnicity, clinical and obstetric history, pregnancy outcome, and C-peptide level.
  
  
  RESULTS
  A total of 813 women (79.6%) were normal, 138 (13.5%) had MGH, and 71 (6.9%) had GDM. There was a stepwise significant increase in mean fasting glucose (3.6 +/- 0.4, 3.9 +/- 0.4, and 4.7 +/- 0.7 mmol/l, respectively) and C-peptide level (0.60 [0.1-2.4], 0.86 [0.3-2.0], and 1.00 [0.5-1.6] nmol/l, respectively) among the three diagnostic groups. Maternal age, non-Caucasian ethnicity, and prepregnancy BMI were associated with GDM, whereas only maternal age and prepregnancy BMI were associated with MGH. A positive correlation between levels of fasting glucose and C-peptide was found in control women (r = 0.39 [95% CI 0.31-0.46]). A similar result was seen in MGH women (r = 0.38 [95% CI 0.23-0.52]), whereas the correlation between fasting glucose and C-peptide was nearly lost in GDM women (r = 0.14 [CI -0.09 to 0.36]). The fasting C-peptide-to-glucose ratio was reduced by 60% in GDM patients versus control subjects and MGH patients (0.41 +/- 0.25 vs. 0.70 +/- 0.20 and 0.73 +/- 0.23, P < 0.001).
  
  
  CONCLUSIONS
  Of the well-known independent determinants of GDM, only maternal age and prepregnancy BMI were associated with MGH. It appears that additional factors promoting loss of beta-cell function distinguish MGH from GDM. One of these factors appears to be ethnicity.
authors.affiliation: Department of Clinical Chemistry and Haematology, Onze Lieve Vrouwe Gasthuis, Amsterdam, the Netherlands. rnm.weijers@wolmail.nl
authors.forename: Rob N M
authors.initials: RN
authors.lastname: Weijers
authors.forename: Dick J
authors.initials: DJ
authors.lastname: Bekedam
authors.forename: Yvo M
authors.initials: YM
authors.lastname: Smulders
mesh_terms: D000328:Adult; D001034:Apgar Score; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D002096:C-Peptide / Q000097:blood; D016640:Diabetes, Gestational / Q000453:epidemiology / Q000503:physiopathology*; D005006:Ethnicity; D005190:Family; D005215:Fasting; D005260:Female; D005865:Gestational Age; D005951:Glucose Tolerance Test; D006801:Humans; D006943:Hyperglycemia / Q000453:epidemiology / Q000503:physiopathology*; D006973:Hypertension / Q000503:physiopathology; D007231:Infant, Newborn; D008423:Maternal Age; D009426:Netherlands / Q000453:epidemiology; D010298:Parity; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology / Q000503:physiopathology*; D011249:Pregnancy Complications, Cardiovascular / Q000503:physiopathology; D018566:Pregnancy, High-Risk; D012016:Reference Values; D044465:White People
chemical_list: D001786:Blood Glucose; D002096:C-Peptide