title: 25-Hydroxyvitamin D is associated with plasma renin activity and the pressor response to dietary sodium intake in Caucasians.
abstract: BACKGROUND
  Concentrations of 1,25-hydroxyvitamin D have been positively associated with dietary sodium and salt sensitivity (SS) of blood pressure (BP), and inversely with plasma renin activity (PRA). We investigated the association between PRA and 25-hydroxyvitamin D (25OHD), the most clinically relevant vitamin D metabolite, and whether 25OHD associates with SS of BP in renin phenotypes of hypertension.
  
  
  METHODS
  We performed cross-sectional analyses on 223 Caucasian subjects with hypertension maintained in high and low dietary sodium balance. Subjects were distinguished as having low-renin (LR) or normal-renin (NR) hypertension. Multivariable linear regression was used to evaluate adjusted relationships.
  
  
  RESULTS
  Increasing 25OHD concentrations were inversely associated with PRA (p < 0.05) on both salt diets. Furthermore, 25OHD was associated with SS of BP in LR hypertension (b = 0.62, p = 0.04), but not in NR hypertension (b = 0.06, p = 0.59). In an adjusted multivariable interaction model, renin status (LR vs. NR) was a significant effect modifier of the relationship between 25OHD and SS of BP (p = 0.04).
  
  
  CONCLUSIONS
  Our findings suggest that 25OHD is inversely associated with PRA and positively associated with SS of BP in LR hypertension subjects. These results extend and support prior evidence indicating an interaction between dietary sodium, the RAS, and vitamin D that influences BP in hypertension.
authors.affiliation: Division of Endocrinology, Diabetes, and Hypertension, Brigham and Women's Hospital and Harvard Medical School, USA. avaidya1@partners.org
authors.forename: Anand
authors.initials: A
authors.lastname: Vaidya
authors.forename: John P
authors.initials: JP
authors.lastname: Forman
authors.forename: Paul N
authors.initials: PN
authors.lastname: Hopkins
authors.forename: Ellen W
authors.initials: EW
authors.lastname: Seely
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Williams
mesh_terms: D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012083:Renin / Q000097:blood*; D012982:Sodium, Dietary / Q000494:pharmacology*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D044465:White People
chemical_list: D012982:Sodium, Dietary; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D012083:Renin