DOI: 10.1097/01.aoa.0000370529.36425.2c
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Issn Print: 0275-665X
Publication Date: 2010/06/01
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Excerpt
The DNBC enrolled 101,045 pregnant women from 1996 through 2002 of which 57,346 were included in this analysis. Appropriate candidates for the study were chosen on the basis of telephonic interviews that identified confounding variables. Women were also excluded from the study if they failed to complete a food frequency questionnaire (FFQ). The women were interviewed by telephone twice antenatally and at 6 and 18 months after delivery. The median gestational age for the 2 antenatal interviews was 16 and 31 completed weeks. The self-administered FFQ was mailed at gestational week 25 and asked for information about intake from diet and supplements during the previous 4 weeks. Data on intake of vitamins C and E were extracted from the FFQs. Preeclampsia diagnoses were obtained from the Danish National Patient Registry following accepted definitions for hypertension and proteinuria. Multivariate logistic regression analysis was used to control for parity, smoking history, maternal age, maternal height, body mass index, socioeconomic status, social situation, and physical activity.
Mean intakes of vitamins C and E from diet were estimated at 131.3 mg and 6.87 mg, respectively; mean intakes from all types of supplements were 85.6 mg and 10.8 mg, respectively. When nutrient contributions from diet and supplements were combined, 2.6% and 9.6% of women had intakes of vitamins C and E, respectively, below the Nordic Recommended Daily Allowance. Mean energy intake was 10,269 kJ/d. Vitamin intake was associated with age, prepregnancy body mass index, smoking, parity, and socioeconomic status. Primiparity, nonsmoking, low height, and pre-pregnant overweight or obesity status were associated with an increased incidence of preeclampsia, severe preeclampsia, eclampsia, and HELLP syndrome. Of 57,346 women, 1487 (2.6%) had preeclampsia and 337 (0.6%) had severe preeclampsia/eclampsia/HELLP. When all classifications of preeclampsia were included, an elevated risk for the disorder was not associated with levels of vitamin C or E intake. However, for severe preeclampsia/eclampsia/HELLP, a trend suggested a protective effect of increasing dietary intake of vitamin C from ≤70 mg/d [odds ratio (OR), 1.21; 95% confidence interval (CI), 0.83-1.75] to > 275 mg/d (OR, 0.70; CI, 0.40-1.23, trend test P=0.01) but the trend was not as apparent when intake of supplements of vitamin C were included (OR, 1.27; CI, 0.58-2.79 for intake ≤70 mg/d; OR, 0.85; CI, 0.59-1.21 for intake >275 mg/d). A high level of vitamin E intake (>18 mg/d) suggested an association with an increased incidence of severe preeclampsia/eclampsia/HELLP (OR, 1.46; CI, 1.02-2.09). When intake of vitamins C and E were dichotomized at 275 mg and 18 mg, respectively, no significant interaction between the 2 vitamins affecting the rates of preeclampsia or severe preeclampsia/eclampsia/HELLP was found. This relationship held when dietary intakes of the 2 vitamins were dichotomized at 275 mg and 10.5 mg, respectively.
The incidence of severe preeclampsia/eclampsia/HELLP may decrease with increasing intake of vitamin C. In contrast, severe preeclampsia may be increased in women who consume large amounts of vitamin E. This study failed to show that high intake of both vitamins C and E is associated with a reduced risk of preeclampsia.
