Maternal plasma ascorbic Acid (vitamin C) and risk of gestational diabetes mellitus.
BACKGROUND
Antioxidants, particularly vitamin C (ascorbic acid), have the capacity to influence glucose tolerance. Modification of diet could reduce the likelihood of developing gestational diabetes mellitus.


METHODS
In a prospective cohort study of pregnant women, we studied the association of maternal plasma ascorbic acid concentrations, measured at an average of 13 weeks' gestation, with subsequent risk of gestational diabetes. Maternal plasma ascorbic acid concentrations were determined using automated enzymatic procedures. Dietary vitamin C intake during the periconceptional period and early pregnancy was ascertained using a semiquantitative food frequency questionnaire. We fitted generalized linear models to derive estimates of relative risks and 95% confidence intervals (CIs).


RESULTS
Approximately 4% (n = 33) of 755 women who completed pregnancy developed gestational diabetes mellitus. Plasma ascorbic acid concentrations were inversely associated with the risk of gestational diabetes (P for trend = 0.023). After adjusting for maternal age, race, prepregnancy adiposity, parity, family history of type 2 diabetes, and household income, women with plasma ascorbic acid <55.9 micromol/L (lowest quartile) experienced a 3.1-fold increased risk of gestational diabetes (95% CI = 1.0 - 9.7) compared with women whose concentrations were > or = 74.6 micromol/L (upper quartile). Women who consumed <70 mg vitamin C daily experienced a 1.8-fold increased risk of gestational diabetes compared with women who consumed higher amounts (95% CI = 0.8 - 4.4).


CONCLUSIONS
If confirmed, our results raise the possibility that current efforts to encourage populations to consume diets rich in antioxidants, including vitamin C, could reduce the occurrence of gestational diabetes mellitus.
Department of Epidemiology, University of Washington School of Public Health and Community Medicine, Seattle, Washington, USA. clinn@u.washington.edu
Cuilin
C
Zhang
Michelle A
MA
Williams
Tanya K
TK
Sorensen
Irena B
IB
King
Mark M
MM
Kestin
Mary Lou
ML
Thompson
Wendy M
WM
Leisenring
Edward E
EE
Dashow
David A
DA
Luthy
D000328:Adult; D001205:Ascorbic Acid / Q000097:blood*; D015331:Cohort Studies; D016640:Diabetes, Gestational / Q000097:blood / Q000453:epidemiology*; D005260:Female; D006801:Humans; D016014:Linear Models; D008429:Maternal Welfare; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014861:Washington / Q000453:epidemiology
D001205:Ascorbic Acid