title: Vitamin D, parathyroid hormone, and cardiovascular events among older adults.
abstract: OBJECTIVE
  The aim of this study was to evaluate associations of 25-hydroxyvitamin D (25-OHD) and parathyroid hormone (PTH) concentrations separately and in combination with incident cardiovascular events and mortality during 14 years of follow-up in the CHS (Cardiovascular Health Study).
  
  
  BACKGROUND
  Vitamin D deficiency and PTH excess are common in older adults and may adversely affect cardiovascular health.
  
  
  METHODS
  A total of 2,312 participants who were free of cardiovascular disease at baseline were studied. Vitamin D and intact PTH were measured from previously frozen serum using mass spectrometry and a 2-site immunoassay. Outcomes were adjudicated cases of myocardial infarction, heart failure, cardiovascular death, and all-cause mortality.
  
  
  RESULTS
  There were 384 participants (17%) with serum 25-OHD concentrations <15 ng/ml and 570 (25%) with serum PTH concentrations ≥ 65 pg/ml. After adjustment, each 10 ng/ml lower 25-OHD concentration was associated with a 9% greater (95% confidence interval [CI]: 2% to 17% greater) relative hazard of mortality and a 25% greater (95% CI: 8% to 44% greater) relative hazard of myocardial infarction. Serum 25-OHD concentrations <15 ng/ml were associated with a 29% greater (95% CI: 5% to 55% greater) risk for mortality. Serum PTH concentrations ≥ 65 pg/ml were associated with a 30% greater risk for heart failure (95% CI: 6% to 61% greater) but not other outcomes. There was no evidence of an interaction between serum 25-OHD and PTH concentrations and cardiovascular events.
  
  
  CONCLUSIONS
  Among older adults, 25-OHD deficiency is associated with myocardial infarction and mortality; PTH excess is associated with heart failure. Vitamin D and PTH might influence cardiovascular risk through divergent pathways.
authors.affiliation: Kidney Research Institute, University of Washington, Seattle, WA, USA. brk@u.washington.edu
authors.forename: Bryan
authors.initials: B
authors.lastname: Kestenbaum
authors.forename: Ronit
authors.initials: R
authors.lastname: Katz
authors.forename: Ian
authors.initials: I
authors.lastname: de Boer
authors.forename: Andy
authors.initials: A
authors.lastname: Hoofnagle
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Sarnak
authors.forename: Michael G
authors.initials: MG
authors.lastname: Shlipak
authors.forename: Nancy S
authors.initials: NS
authors.lastname: Jenny
authors.forename: David S
authors.initials: DS
authors.lastname: Siscovick
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002318:Cardiovascular Diseases / Q000097:blood* / Q000175:diagnosis* / Q000401:mortality; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood*; D011446:Prospective Studies; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D