Serum 25-hydroxyvitamin D concentration and risk for major clinical disease events in a community-based population of older adults: a cohort study

Ann Intern Med. 2012 May 1;156(9):627-34. doi: 10.7326/0003-4819-156-9-201205010-00004.

Abstract

Background: Circulating concentrations of 25-hydroxyvitamin D [25-(OH)D] are used to define vitamin D deficiency. Current clinical 25-(OH)D targets based on associations with intermediate markers of bone metabolism may not reflect optimal levels for other chronic diseases and do not account for known seasonal variation in 25-(OH)D concentration.

Objective: To evaluate the relationship of 25-(OH)D concentration with the incidence of major clinical disease events that are pathophysiologically relevant to vitamin D.

Design: Cohort study.

Setting: The Cardiovascular Health Study conducted in 4 U.S. communities. Data from 1992 to 2006 were included in this analysis.

Participants: 1621 white older adults.

Measurements: Serum 25-(OH)D concentration (using a high-performance liquid chromatography-tandem mass spectrometry assay that conforms to National Institute of Standards and Technology reference standards) and associations with time to a composite outcome of incident hip fracture, myocardial infarction, cancer, or death.

Results: Over a median 11-year follow-up, the composite outcome occurred in 1018 participants (63%). Defining events included 137 hip fractures, 186 myocardial infarctions, 335 incidences of cancer, and 360 deaths. The association of low 25-(OH)D concentration with risk for the composite outcome varied by season (P = 0.057). A concentration lower than a season-specific Z score of -0.54 best discriminated risk for the composite outcome and was associated with a 24% higher risk in adjusted analyses (95% CI, 9% to 42%). Corresponding season-specific 25-(OH)D concentrations were 43, 50, 61, and 55 nmol/L (17, 20, 24, and 22 ng/mL) in winter, spring, summer, and autumn, respectively.

Limitation: The observational study was restricted to white participants.

Conclusion: Threshold concentrations of 25-(OH)D associated with increased risk for relevant clinical disease events center near 50 nmol/L (20 ng/mL). Season-specific targets for 25-(OH)D concentration may be more appropriate than static targets when evaluating health risk.

Primary funding source: National Institutes of Health.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Cause of Death
  • Female
  • Follow-Up Studies
  • Hip Fractures / epidemiology*
  • Humans
  • Male
  • Myocardial Infarction / epidemiology*
  • Neoplasms / epidemiology*
  • Proportional Hazards Models
  • Risk Assessment
  • Risk Factors
  • Seasons
  • United States / epidemiology
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood
  • Vitamin D Deficiency / blood
  • Vitamin D Deficiency / complications*

Substances

  • Vitamin D
  • 25-hydroxyvitamin D

Grant support