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Vitamin D supplements and cancer incidence and mortality: a meta-analysis.

Keum N, Giovannucci E - Br. J. Cancer (2014)

Bottom Line: Observational studies suggest that effects of vitamin D may be stronger for cancer mortality than for incidence.Over 2-7 years of duration, vitamin D supplementations had little effect on total cancer incidence (400-1100 IU per day, summary relative risk (RR)=1.00, 95% confidence interval (CI)=0.94-1.06, I(2)=0%; four RCTs with combined 4333 cases), but significantly reduced total cancer mortality (400-833 IU per day, summary RR=0.88, 95% CI=0.78-0.98, I(2)=0%, three RCTs with combined 1190 deaths).Over 2-7 years of duration, the benefit of vitamin D supplementation may be limited to cancer mortality.

View Article: PubMed Central - PubMed

Affiliation: Departments of Nutrition and Epidemiology, Harvard School of Public Health, Building 2, 3rd floor, 655 Huntington Avenue, Boston, MA 02115, USA.

ABSTRACT

Background: Observational studies suggest that effects of vitamin D may be stronger for cancer mortality than for incidence. Yet, existing randomised controlled trials (RCTs) of vitamin D supplementation have limited power to examine the relationships as their primary end points are not cancer incidence or mortality.

Methods: Meta-analyses of RCTs of vitamin D supplementation and total cancer incidence and mortality were conducted.

Results: Over 2-7 years of duration, vitamin D supplementations had little effect on total cancer incidence (400-1100 IU per day, summary relative risk (RR)=1.00, 95% confidence interval (CI)=0.94-1.06, I(2)=0%; four RCTs with combined 4333 cases), but significantly reduced total cancer mortality (400-833 IU per day, summary RR=0.88, 95% CI=0.78-0.98, I(2)=0%, three RCTs with combined 1190 deaths).

Conclusions: Over 2-7 years of duration, the benefit of vitamin D supplementation may be limited to cancer mortality.

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Related in: MedlinePlus

Flowchart of study selection.
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fig1: Flowchart of study selection.

Mentions: To be included, studies had to be a RCT providing information on the effect of vitamin D supplementation (with or without calcium supplementation) on total cancer incidence or mortality. When there were several publications from the same trial, the publication most fully covering the intervention period was selected. This study selection process is summarised in Figure 1.


Vitamin D supplements and cancer incidence and mortality: a meta-analysis.

Keum N, Giovannucci E - Br. J. Cancer (2014)

Flowchart of study selection.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150260&req=5

fig1: Flowchart of study selection.
Mentions: To be included, studies had to be a RCT providing information on the effect of vitamin D supplementation (with or without calcium supplementation) on total cancer incidence or mortality. When there were several publications from the same trial, the publication most fully covering the intervention period was selected. This study selection process is summarised in Figure 1.

Bottom Line: Observational studies suggest that effects of vitamin D may be stronger for cancer mortality than for incidence.Over 2-7 years of duration, vitamin D supplementations had little effect on total cancer incidence (400-1100 IU per day, summary relative risk (RR)=1.00, 95% confidence interval (CI)=0.94-1.06, I(2)=0%; four RCTs with combined 4333 cases), but significantly reduced total cancer mortality (400-833 IU per day, summary RR=0.88, 95% CI=0.78-0.98, I(2)=0%, three RCTs with combined 1190 deaths).Over 2-7 years of duration, the benefit of vitamin D supplementation may be limited to cancer mortality.

View Article: PubMed Central - PubMed

Affiliation: Departments of Nutrition and Epidemiology, Harvard School of Public Health, Building 2, 3rd floor, 655 Huntington Avenue, Boston, MA 02115, USA.

ABSTRACT

Background: Observational studies suggest that effects of vitamin D may be stronger for cancer mortality than for incidence. Yet, existing randomised controlled trials (RCTs) of vitamin D supplementation have limited power to examine the relationships as their primary end points are not cancer incidence or mortality.

Methods: Meta-analyses of RCTs of vitamin D supplementation and total cancer incidence and mortality were conducted.

Results: Over 2-7 years of duration, vitamin D supplementations had little effect on total cancer incidence (400-1100 IU per day, summary relative risk (RR)=1.00, 95% confidence interval (CI)=0.94-1.06, I(2)=0%; four RCTs with combined 4333 cases), but significantly reduced total cancer mortality (400-833 IU per day, summary RR=0.88, 95% CI=0.78-0.98, I(2)=0%, three RCTs with combined 1190 deaths).

Conclusions: Over 2-7 years of duration, the benefit of vitamin D supplementation may be limited to cancer mortality.

Show MeSH
Related in: MedlinePlus