Serum 25-hydroxyvitamin D levels and overall mortality.

A systematic review and meta-analysis of prospective cohort studies.

Ageing Res Rev. 2012 Feb 16.
Schöttker B, Ball D, Gellert C, Brenner H.
Division of Clinical Epidemiology and Aging Research, German Cancer Research Center, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany; Equal contributions on first authors.

OBJECTIVE:
To provide a systematic review and meta-analysis of prospective, population-based cohort studies on the association of serum 25-hydroxyvitamin D (25(OH)D) and all-cause mortality.
METHODS:

Relevant studies were identified by systematically searching Medline, EMBASE and ISI Web of Knowledge. Reported hazard ratios (HRs) for 25(OH)D categories were recalculated employing comprehensive trend estimation from summarized dose-response data and pooled in a random effects model meta-analysis.
RESULTS:

Overall, 12 original studies were included in the review and meta-analysis comprising 32,142 mainly elderly study participants with measured 25(OH)D of whom 6,921 died during follow-up. An inverse association between 25(OH)D levels and all-cause mortality was found in all but two studies that was statistically significant in several of the individual studies.

In meta-analysis, 25(OH)D levels were significantly inversely associated with all-cause mortality with a pooled HR of 0.92 (95% confidence interval: 0.89-0.95) for a 20 nmol/l increase in 25(OH)D levels.

CONCLUSION: In this meta-analysis of prospective, population-based cohort studies, a 20-nmol/l-increase in 25(OH)D levels was associated with an 8% lower mortality in the general elderly population.
This agrees with results from meta-analyses on randomized controlled trials that found a decrease in mortality with vitamin D(3) supplementation of a comparable magnitude.

Highlights

• Systematic review and meta-analysis of 12 population-based cohort studies.
• A 20 nmol/l increase in vitamin D levels was associated with an 8% lower mortality.
• Vitamin D deficiency might be an underestimated underlying cause of premature death.
• Plausible mechanisms how vitamin D influences life expectancy have been suggested.
• Public health approaches to increase vitamin D levels might be easily implemented.

Abbreviations
1,25(OH)2D, 1,25-dihydroxyvitamin D; 25(OH)D, 25-hydroxyvitamin D; 95%-CI, 95% confidence interval; CKD, chronic kidney disease; df, degrees of freedom; ESCPG, Endocrine Society Clinical Practice Guideline; HR, hazard ratio; IOM, Institute of Medicine (USA); PTH, parathyroid hormone; RCT, randomized controlled trial; UV-B, ultraviolet B

Keywords
Vitamin D; Mortality; Cohort Studies; Meta-analysis; Review; Systematic; Elderly

Copyright © 2012. Published by Elsevier B.V.

PMID: 22343489
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See also VitaminDWiki

• All items in Mortality and vitamin D (not just Cardio) 321 items
• 40 ng Vitamin D perhaps optimal for reduced mortality – Meta-analysis Jan 2012
• Dr. Grant on vitamin D and mortality in VitaminDWiki
• Vitamin D with Calcium reduces mortality by 7 percent – meta-analysis May 2012
• Not just elderly: for 180,000 adults, death rate 2X higher if low vitamin D – May 2012