The Association of Maternal Asthma and Early Pregnancy Vitamin D with Risk of Preeclampsia: An Observation From Vitamin D Antenatal Asthma Reduction Trial (VDAART)

BACKGROUND: Maternal asthma, uncontrolled asthma, and low vitamin D levels during pregnancy have been individually linked to increased risk of preeclampsia. OBJECTIVE: To investigate the association of history of physician-diagnosed asthma and uncontrolled asthma status during pregnancy with the risk of preeclampsia and the effects of early pregnancy vitamin D concentrations on this relationship. METHODS: A total of 816 subjects with available pregnancy outcome data and risk factors of interest were analyzed. A group of experienced obstetricians and gynecologists from 3 study centers validated the preeclampsia diagnoses. Vitamin D was measured using the DiaSorin method at 10 to 18 weeks of gestation. The Pregnancy-Asthma Control Test was used to assess asthma control during pregnancy. Criterion-based step-wise variable selection algorithm was applied to investigate the relationships of risk factors of interest (history of asthma diagnosis, uncontrolled asthma during pregnancy, and vitamin D) to preeclampsia. RESULTS: The incidence of preeclampsia was not related to the presence of asthma diagnosis (8.9% with vs 7.4% without). The adjusted odds of preeclampsia controlled for maternal serum 25-hydroxyvitamin D (25OHD) concentrations was higher for women with a higher proportion of uncontrolled asthma months per visit during pregnancy (adjusted odds ratio, 3.55; 95% CI, 1.15-13.0). Adjusting for asthma control status during pregnancy, an additional decrease in the associated preeclampsia risk by 7% was observed for a 10-unit (ng/mL) increase in early pregnancy 25OHD levels (adjusted odds ratio10-unit, 0.60; 95% CI, 0.43-0.82) as compared with the previous risk estimate of preeclampsia associated with low maternal 25OHD unadjusted for asthma control status. CONCLUSIONS: Uncontrolled asthma during pregnancy is associated with an increased risk of preeclampsia. Early pregnancy 25OHD contributes to the association of uncontrolled asthma status with preeclampsia. (C) 2017 American Academy of Allergy, Asthma & Immunology