title: Serum 25-hydroxyvitamin D is not related to cardiac natriuretic peptide in nulliparous and lactating women.
abstract: BACKGROUND
  Vitamin D deficiency is associated with heightened risk of cardiovascular disease. Potential mechanisms include involvement of vitamin D in regulation of renin-angiotensin system and manufacture and secretion of cardiac natriuretic peptides. Our aim was to document relationships between 25 hydroxyvitamin [25(OH)D] and N-terminal pro B-type natriuretic peptide (NT-proBNP) and plasma renin activity (PRA) levels and to document the effect of vitamin D administration on NT-proBNP and PRA levels in vitamin D deficient subjects.
  
  
  METHODS
  Serum 25(OH)D, parathyroid hormone (PTH), plasma or serum NT-proBNP and PRA levels were measured at baseline in nulliparous and lactating women and after 2 months of oral vitamin D2 (2,000 IU/day or 60,000 IU/month) supplementation to lactating women.
  
  
  RESULTS
  Baseline levels of 25(OH)D were low (<50 nmol/L) in most women whereas PRA and NT-proBNP levels were within the normal range. There were no significant correlations between baseline 25(OH)D or PTH with NT-proBNP and PRA. Vitamin D administration over a 2-month period in lactating women was associated with a decline in NT-proBNP (by 9.1 +/- 2.0 pmol/L; p < 0.001) and PRA (by 0.32 +/- 0.17 nmol/L/hr; p = 0.064). However, there were no significant correlations between the changes from baseline in 25(OH)D and either NT-proBNP (r = -0.04, p = 0.8) or PRA (r = -0.04, p = 0.8).
  
  
  CONCLUSIONS
  We found no significant correlations between 25(OH)D or PTH with NT-proBNP and PRA in vitamin D deficient women. Further information is required to clarify the effects of vitamin D administration on cardiac structure and function.
authors.affiliation: Department of Internal Medicine, Faculty of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates. saadih@uaeu.ac.ae
authors.forename: Hussein F
authors.initials: HF
authors.lastname: Saadi
authors.forename: M Gary
authors.initials: MG
authors.lastname: Nicholls
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Frampton
authors.forename: Sheela
authors.initials: S
authors.lastname: Benedict
authors.forename: Javed
authors.initials: J
authors.lastname: Yasin