Are vitamin D intake and serum levels in the mid-trimester of pregnancy associated with preeclampsia? Results from a Brazilian multicentre cohort

Objective: To explore the association between serum levels and food intake of Vitamin D (VD) among healthy women in mid-pregnancy and preeclampsia. Study Design: In a Brazilian multicentre cohort of healthy nulliparous pregnant women from five maternity centres we developed a nested case-control analysis comparing cases with and without preeclampsia. Women were enrolled and followed during prenatal care, including only singleton pregnancies, without any fetal malformations or previous chronic maternal disease. We matched 87 cases of preeclampsia to eligible controls randomly selected in a 1:1 ratio, by age and region. Main outcome measures: Blood samples from these were collected, and a 24-hour recall of food intake was obtained in mid-pregnancy, between 19 and 21 weeks. VD serum levels (25-hydroxyvitamin D) were measured by liquid chromatography-tandem mass spectrometry and were categorized as deficient, insufficient, and sufficient. The dietary intake of VD was estimated with the 24-hour diet recall applied at the same time and from supplementation. Maternal characteristics and VD levels were compared between cases and controls with OR and respective 95 %CI. Multivariate analysis using the Path method was used to assess relationships among VD, PE, BMI, skin colour/ethnicity, and diet. Results: The maternal characteristics of both groups were similar, except for the higher occurrence of obesity among women with preeclampsia (OR 3.47, 95 %CI 1.48-8.65). Dietary intake of VD was similar in both groups, and most of the women in both groups consumed insufficient VD (82.2 vs 79.3 % in the groups with and without PE). Conclusions: Levels and dietary intake of VD were not associated with PE in this Brazilian sample of healthy pregnant women; however, BMI and skin colour/ethnicity were associated with PE.