title: Serum 25-hydroxyvitamin D and parathyroid hormone in relation to plasma B-type natriuretic peptide: the Hoorn Study.
abstract: OBJECTIVE
  A disturbed vitamin D-parathyroid hormone (PTH)-calcium axis may play a role in the pathogenesis of heart failure. Therefore, we investigated whether lower 25-hydroxyvitamin D (25(OH)D) and higher PTH are cross sectionally and after 8 years of follow-up associated with higher B-type natriuretic peptide (BNP) levels in older men and women.
  
  
  METHODS
  We measured baseline 25(OH)D, PTH, and BNP in 502 subjects in 2000-2001 in the Hoorn Study, a population-based cohort. Follow-up BNP was available in 2007-2009 in 278 subjects. Subjects were categorized according to season- and sex-specific quartiles of 25(OH)D and PTH at baseline. We studied the association of 25(OH)D and PTH quartiles with BNP using linear regression analyses adjusting for confounders. Analyses were stratified by kidney function estimated glomerular filtration rate (eGFR; ≤60 ml/min per 1.73 m(2)) because of significant interaction.
  
  
  RESULTS
  At baseline, subjects had a mean age of 69.9±6.6 years, mean 25(OH)D level was 52.2±19.5 nmol/l and mean PTH 6.1±2.4 pmol/l. Cross sectionally, 25(OH)D was associated with BNP in subjects with impaired kidney function (eGFR ≤60 ml/min) only. The association attenuated after adjustment for PTH. PTH was cross sectionally associated with BNP, also in subjects with impaired kidney function only: regression coefficient of highest quartile 9.9 pmol/l (95% confidence interval 2.5, 17.4) with a significant trend across quartiles. Neither 25(OH)D nor PTH was associated with BNP in longitudinal analyses.
  
  
  CONCLUSIONS
  This study showed overall no strong association between 25(OH)D and BNP. However, PTH was associated with BNP in subjects with impaired kidney function and may point to a potential role in myocardial function.
authors.affiliation: Department of Health Sciences, Faculty of Earth and Life Sciences EMGO+, Institute for Health and Care Research, VU University Amsterdam De Boelelaan 10851081 HV, Amsterdam The Netherlands.
authors.forename: Adriana J
authors.initials: AJ
authors.lastname: van Ballegooijen
authors.forename: Marjolein
authors.initials: M
authors.lastname: Visser
authors.forename: Marieke B
authors.initials: MB
authors.lastname: Snijder
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Dekker
authors.forename: Giel
authors.initials: G
authors.lastname: Nijpels
authors.forename: Coen D A
authors.initials: CD
authors.lastname: Stehouwer
authors.forename: Michaela
authors.initials: M
authors.lastname: Diamant
authors.forename: Ingeborg A
authors.initials: IA
authors.lastname: Brouwer
keywords: B-type natriuretic peptide; epidemiology; parathyroid hormone; vitamin D