Vitamin C and the risk of preeclampsia--results from dietary questionnaire and plasma assay.
BACKGROUND
Oxidative stress plays an important role in the pathophysiology of preeclampsia.


METHODS
In a case-control study of 109 women with preeclampsia and 259 controls, maternal dietary and plasma vitamin C in relation to preeclampsia risk were assessed. Dietary intake during the periconceptional period and pregnancy was ascertained using a semiquantitative food frequency questionnaire. Logistic regression procedures were used to derive odds ratios (OR) and 95% confidence intervals (CI). Plasma ascorbic acid was determined using automated enzymatic procedures.


RESULTS
After adjusting for maternal age, parity, prepregnancy body mass index, and energy intake, women who consumed <85 mg of vitamin C daily (below the recommended dietary allowance), as compared with others, experienced a doubling in preeclampsia risk (OR = 2.1; 95% CI = 1.1-3.9). The OR for extreme quartiles of plasma ascorbic acid (<42.5 vs > or = 63.3 micromol/liter) was 2.3 (95% CI = 1.1-4.6). Compared with women in the highest quartile, those with plasma ascorbic acid <34.6 micromol/liter (lowest decile) experienced a 3.8-fold increased risk of preeclampsia (95% CI = 1.7-8.8).


CONCLUSIONS
Our results, if confirmed, would suggest that current public health efforts to increase intake of fruits and vegetables rich in vitamin C and other antioxidants may reduce the risk of preeclampsia.
Zhang
Cuilin
C
Department of Epidemiology, University of Washington School of Public Health and Community Medicine, 1959 NE Pacific Avenue, Seattle, WA 98195, USA. clinn@u.washington.edu
Williams
Michelle A
MA
King
Irena B
IB
Dashow
Edward E
EE
Sorensen
Tanya K
TK
Frederick
Ihunnaya O
IO
Thompson
Mary Lou
ML
Luthy
David A
DA
D000293:Adolescent; D000328:Adult; D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000097:blood*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D011225:Pre-Eclampsia / Q000097:blood* / Q000503:physiopathology* / Q000517:prevention & control; D011247:Pregnancy; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014861:Washington / Q000453:epidemiology
D001205:Ascorbic Acid