The relationship of hypovitaminosis D and IL-6 in preeclampsia.
OBJECTIVE
Vitamin D deficiency has been linked to the pathogenesis of preeclampsia. Given the demonstrated antiinflammatory function of vitamin D in multiple organ systems including trophoblast cells and placenta, we hypothesized that vitamin D deficiency contributes to the development of preeclampsia through increased inflammation, as indicated by elevated interleukin (IL)-6 concentrations.


METHODS
Plasma samples from a large preeclampsia cohort study were examined in 100 preeclamptic and 100 normotensive pregnant women. Comparisons of vitamin D and IL-6 concentrations used Student t test and χ(2) test or their nonparametric counterparts. A logistic regression model assessed the association among vitamin D, IL-6 concentrations, and preeclampsia risk.


RESULTS
The mean concentration of 25-hydroxyvitamin D was 49.4 ± 22.6 nmol/L in normotensives and 42.3 ± 17.3 nmol/L in preeclamptic women (P = .01). The median (interquartile range: Q1, Q3) concentrations of IL-6 were 2.0 (1.3, 3.4) pg/mL and 4.4 (2.2, 10.0) pg/mL in the control and preeclampsia groups, respectively (P < .01). We observed a significant association between IL-6 elevation and preeclampsia (odds ratio, 4.4; 95% confidence interval, 1.8-10.8; P < .01) and between vitamin D deficiency and preeclampsia (odds ratio, 4.2; 95% confidence interval, 1.4-12.8; P = .04). However, there was no association between vitamin D deficiency and IL-6 elevation.


CONCLUSIONS
Third-trimester IL-6 elevation and vitamin D deficiency were independently associated with the risk of preeclampsia. We found no evidence to support the hypothesis that vitamin D deficiency alters the pathogenesis of preeclampsia by activation of inflammation as assessed by IL-6 concentration.
Department of Internal Medicine, University of Iowa Hospitals and Clinics, Iowa City, IA.
Lai
L
Xu
Biostatistics/Epidemiology/Research Design Core, Center for Clinical and Translational Sciences, University of Texas Health Science Center, Houston, TX.
Minjae
M
Lee
Magee-Womens Research Institute and Foundation, University of Pittsburgh School of Medicine, Pittsburgh, PA; Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, PA.
Arun
A
Jeyabalan
Magee-Womens Research Institute and Foundation, University of Pittsburgh School of Medicine, Pittsburgh, PA; Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, PA; Department of Epidemiology, University of Pittsburgh School of Medicine, Pittsburgh, PA; Clinical and Translational Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA. Electronic address: jroberts@mwri.magee.edu.
James M
JM
Roberts
D000328:Adult; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D011225:Pre-Eclampsia / Q000097:blood / Q000209:etiology*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000097:blood; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications*
D015850:Interleukin-6; D014807:Vitamin D; C104450:25-hydroxyvitamin D
inflammation; interleukin-6; preeclampsia; pregnancy; vitamin D