Review: Evidence for the effectiveness of vitamin D and calcium for reducing CV outcomes, cancer, and death is limited

Joel A. Simon

doi:10.7326/0003-4819-151-10-200911170-02005

Question

Does vitamin D, calcium, or a combination of both improve health outcomes?

Review scope

Included studies evaluated oral vitamin D and calcium supplements with known doses, used alone or together, in generally healthy people. Exclusion criteria included studies of older adults (mean age ≥ 65 y) who had a disease other than hypertension at baseline and those of younger adults that included > 20% of people with diseases at baseline. Additional selection criteria were used for each outcome and for systematic reviews. This abstract focuses on a subset of evaluated outcomes in randomized controlled trials (RCTs): mortality, cardiovascular (CV) disease, and cancer.

Review methods

MEDLINE and Cochrane CENTRAL (to Apr 2009), Cochrane Database of Systematic Reviews and Health Technology Assessments (to Dec 2008), and reference lists were searched for English-language RCTs; prospective, nonrandomized, comparative studies; prospective longitudinal or nested case–control studies; and systematic reviews. 165 studies, including 60 RCTs, and 11 systematic reviews met the selection criteria.

Main results

The Table shows selected results.

Conclusion

Evidence for the effectiveness of vitamin D, calcium, or a combination of both for improving health outcomes is limited.

Vitamin D, calcium, or a combination of both vs placebo or no treatment*

Treatments	Outcomes	Number of RCTs (n)	Follow-up	Results†
Vitamin D	Total CV events	1 (2686)	5 y	RR 0.90, 95% CI 0.77 to 1.06
	Total cancer	1 (891)	4 y	Incidence: RR 0.76, CI 0.38 to 1.55‡
		1 (2686)	5 y	Incidence: HR 1.09, CI 0.86 to 1.36 Mortality: HR 0.86, CI 0.61 to 1.20
	Colorectal cancer	1 (2686)	5 y	Incidence: HR 1.02, CI 0.60 to 1.74 Mortality: HR 0.62, CI 0.24 to 1.60
	Mortality	4 (13 833)	3 to 5 y	Pooled RR 0.97, CI 0.92 to 1.02
Calcium	Total cancer	1 (733)	4 y	Incidence: RR 0.53, CI 0.27 to 1.03
	Colorectal cancer	2 (1346)	Not reported	Incidence: Pooled OR 0.34, CI 0.05 to 2.15
Vitamin D + calcium	CV events§	1 (36 282)	7 y	HR 1.08, CI 0.99 to 1.19
	Total cancer	1 (36 282)	7 y	Incidence: HR 0.98, CI 0.91 to 1.05 Mortality: HR 0.89, CI 0.77 to 1.03
		1 (734)	4 y	Incidence: RR 0.40, CI 0.20 to 0.82
	Colorectal cancer	1 (36 282)	7 y	Incidence: HR 1.08, CI 0.86 to 1.34 Mortality: HR 0.82, CI 0.52 to 1.29
	Breast cancer	1 (36 282)	7 y	Incidence: HR 0.96, CI 0.86 to 1.07 Mortality: HR 0.99, CI 0.55 to 1.76
	Mortality	11 (44 688)	Median 2 y	Pooled RR 0.93, CI 0.86 to 1.01

Treatments	Outcomes	Number of RCTs (n)	Follow-up	Results†
Vitamin D	Total CV events	1 (2686)	5 y	RR 0.90, 95% CI 0.77 to 1.06
	Total cancer	1 (891)	4 y	Incidence: RR 0.76, CI 0.38 to 1.55‡
		1 (2686)	5 y	Incidence: HR 1.09, CI 0.86 to 1.36 Mortality: HR 0.86, CI 0.61 to 1.20
	Colorectal cancer	1 (2686)	5 y	Incidence: HR 1.02, CI 0.60 to 1.74 Mortality: HR 0.62, CI 0.24 to 1.60
	Mortality	4 (13 833)	3 to 5 y	Pooled RR 0.97, CI 0.92 to 1.02
Calcium	Total cancer	1 (733)	4 y	Incidence: RR 0.53, CI 0.27 to 1.03
	Colorectal cancer	2 (1346)	Not reported	Incidence: Pooled OR 0.34, CI 0.05 to 2.15
Vitamin D + calcium	CV events§	1 (36 282)	7 y	HR 1.08, CI 0.99 to 1.19
	Total cancer	1 (36 282)	7 y	Incidence: HR 0.98, CI 0.91 to 1.05 Mortality: HR 0.89, CI 0.77 to 1.03
		1 (734)	4 y	Incidence: RR 0.40, CI 0.20 to 0.82
	Colorectal cancer	1 (36 282)	7 y	Incidence: HR 1.08, CI 0.86 to 1.34 Mortality: HR 0.82, CI 0.52 to 1.29
	Breast cancer	1 (36 282)	7 y	Incidence: HR 0.96, CI 0.86 to 1.07 Mortality: HR 0.99, CI 0.55 to 1.76
	Mortality	11 (44 688)	Median 2 y	Pooled RR 0.93, CI 0.86 to 1.01

*CV = cardiovascular; HR = hazard ratio; OR = odds ratio; RCT = randomized controlled trial; RR = relative risk; other abbreviations defined in Glossary. Individual studies were all graded B on a 3-category (A to C) quality scale.

†Values < 1 favor treatment.

‡Calcium was included in both treatment groups in some trials.

§Composite of myocardial infarction, coronary heart disease mortality, coronary artery bypass graft, or percutaneous coronary intervention.

ACP Journal Club |17 November 2009

Review: Evidence for the effectiveness of vitamin D and calcium for reducing CV outcomes, cancer, and death is limited

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ACP Journal Club |17 November 2009

Review: Evidence for the effectiveness of vitamin D and calcium for reducing CV outcomes, cancer, and death is limited

Abstract

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