@article {1384, title = {Serum 25-hydroxyvitamin D concentration and risk for major clinical disease events in a community-based population of older adults: a cohort study.}, journal = {Ann Intern Med}, volume = {156}, year = {2012}, month = {2012 May 01}, pages = {627-34}, 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.

}, keywords = {Aged, Cause of Death, Female, Follow-Up Studies, Hip Fractures, Humans, Male, Myocardial Infarction, Neoplasms, Proportional Hazards Models, Risk Assessment, Risk Factors, Seasons, United States, Vitamin D, Vitamin D Deficiency}, issn = {1539-3704}, doi = {10.7326/0003-4819-156-9-201205010-00004}, author = {de Boer, Ian H and Levin, Gregory and Robinson-Cohen, Cassianne and Biggs, Mary L and Hoofnagle, Andy N and Siscovick, David S and Kestenbaum, Bryan} }