Giuseppe
Emeritus
[Source: British Medical Journal, full page: (LINK). Abstract, edited.]
Research
Vitamin D and risk of cause specific death: systematic review and meta-analysis of observational cohort and randomised intervention studies
<CITE><ABBR>BMJ </ABBR>2014; 348 doi: http://dx.doi.org/10.1136/bmj.g1903 (Published 1 April 2014) / Cite this as: <ABBR>BMJ</ABBR> 2014;348:g1903</CITE>
<CITE></CITE>
<CITE></CITE>Rajiv Chowdhury, 1, Setor Kunutsor, 1, Anna Vitezova, 2, Clare Oliver-Williams, 1, Susmita Chowdhury, 3, Jessica C Kiefte-de-Jong, 2, Hassan Khan, 1, Cristina P Baena, 4, Dorairaj Prabhakaran, 5, Moshe B Hoshen, 6, Becca S Feldman, 6, An Pan, 7 8, Laura Johnson, 9, Francesca Crowe, 10, Frank B Hu, 7, Oscar H Franco, 2
Author Affiliations: <SUP>1</SUP>Department of Public Health and Primary Care, University of Cambridge, Strangeways Research Laboratory, Cambridge CB1 8RN, UK; <SUP>2</SUP>Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands; <SUP>3</SUP>Public Health Genomics Foundation, Cambridge, UK; <SUP>4</SUP>Pontif?cia Universidade Cat?lica do Paran?, Brazil; <SUP>5</SUP>Centre for Chronic Disease Control, New Delhi, India; <SUP>6</SUP>Clalit Research Institute and Chief Physician?s Office, Clalit Health Services, Israel; <SUP>7</SUP>Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, US; <SUP>8</SUP>National University of Singapore, Republic of Singapore; <SUP>9</SUP>School for Policy Research, University of Bristol, UK; <SUP>10</SUP>Cancer Epidemiology Unit, University of Oxford, Oxford, UK
Correspondence to: R Chowdhury rajiv.chowdhury@phpc.cam.ac.uk or O H Franco o.franco@erasmusmc.nl
Accepted 27 February 2014
Abstract
Objective
To evaluate the extent to which circulating biomarker and supplements of vitamin D are associated with mortality from cardiovascular, cancer, or other conditions, under various circumstances.
Design
Systematic review and meta-analysis of observational studies and randomised controlled trials.
Data sources
Medline, Embase, Cochrane Library, and reference lists of relevant studies to August 2013; correspondance with investigators.
Study selection
Observational cohort studies and randomised controlled trials in adults, which reported associations between vitamin D (measured as circulating 25-hydroxyvitamin D concentration or vitamin D supplement given singly) and cause specific mortality outcomes.
Data extraction
Data were extracted by two independent investigators, and a consensus was reached with involvement of a third. Study specific relative risks from 73 cohort studies (849 412 participants) and 22 randomised controlled trials (vitamin D given alone versus placebo or no treatment; 30 716 participants) were meta-analysed using random effects models and were grouped by study and population characteristics.
Results
In the primary prevention observational studies, comparing bottom versus top thirds of baseline circulating 25-hydroxyvitamin D distribution, pooled relative risks were 1.35 (95% confidence interval 1.13 to 1.61) for death from cardiovascular disease, 1.14 (1.01 to 1.29) for death from cancer, 1.30 (1.07 to 1.59) for non-vascular, non-cancer death, and 1.35 (1.22 to 1.49) for all cause mortality. Subgroup analyses in the observational studies indicated that risk of mortality was significantly higher in studies with lower baseline use of vitamin D supplements<SUB>.</SUB> In randomised controlled trials, relative risks for all cause mortality were 0.89 (0.80 to 0.99) for vitamin D<SUB>3</SUB> supplementation and 1.04 (0.97 to 1.11) for vitamin D<SUB>2</SUB> supplementation<SUB>.</SUB> The effects observed for vitamin D<SUB>3</SUB> supplementation remained unchanged when grouped by various characteristics. However, for vitamin D<SUB>2</SUB> supplementation, increased risks of mortality were observed in studies with lower intervention doses and shorter average intervention periods.
Conclusions
Evidence from observational studies indicates inverse associations of circulating 25-hydroxyvitamin D with risks of death due to cardiovascular disease, cancer, and other causes. Supplementation with vitamin D<SUB>3</SUB> significantly reduces overall mortality among older adults; however, before any widespread supplementation, further investigations will be required to establish the optimal dose and duration and whether vitamin D<SUB>3</SUB> and D<SUB>2</SUB> have different effects on mortality risk.
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Research
Vitamin D and risk of cause specific death: systematic review and meta-analysis of observational cohort and randomised intervention studies
<CITE><ABBR>BMJ </ABBR>2014; 348 doi: http://dx.doi.org/10.1136/bmj.g1903 (Published 1 April 2014) / Cite this as: <ABBR>BMJ</ABBR> 2014;348:g1903</CITE>
<CITE></CITE>
<CITE></CITE>Rajiv Chowdhury, 1, Setor Kunutsor, 1, Anna Vitezova, 2, Clare Oliver-Williams, 1, Susmita Chowdhury, 3, Jessica C Kiefte-de-Jong, 2, Hassan Khan, 1, Cristina P Baena, 4, Dorairaj Prabhakaran, 5, Moshe B Hoshen, 6, Becca S Feldman, 6, An Pan, 7 8, Laura Johnson, 9, Francesca Crowe, 10, Frank B Hu, 7, Oscar H Franco, 2
Author Affiliations: <SUP>1</SUP>Department of Public Health and Primary Care, University of Cambridge, Strangeways Research Laboratory, Cambridge CB1 8RN, UK; <SUP>2</SUP>Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands; <SUP>3</SUP>Public Health Genomics Foundation, Cambridge, UK; <SUP>4</SUP>Pontif?cia Universidade Cat?lica do Paran?, Brazil; <SUP>5</SUP>Centre for Chronic Disease Control, New Delhi, India; <SUP>6</SUP>Clalit Research Institute and Chief Physician?s Office, Clalit Health Services, Israel; <SUP>7</SUP>Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, US; <SUP>8</SUP>National University of Singapore, Republic of Singapore; <SUP>9</SUP>School for Policy Research, University of Bristol, UK; <SUP>10</SUP>Cancer Epidemiology Unit, University of Oxford, Oxford, UK
Correspondence to: R Chowdhury rajiv.chowdhury@phpc.cam.ac.uk or O H Franco o.franco@erasmusmc.nl
Accepted 27 February 2014
Abstract
Objective
To evaluate the extent to which circulating biomarker and supplements of vitamin D are associated with mortality from cardiovascular, cancer, or other conditions, under various circumstances.
Design
Systematic review and meta-analysis of observational studies and randomised controlled trials.
Data sources
Medline, Embase, Cochrane Library, and reference lists of relevant studies to August 2013; correspondance with investigators.
Study selection
Observational cohort studies and randomised controlled trials in adults, which reported associations between vitamin D (measured as circulating 25-hydroxyvitamin D concentration or vitamin D supplement given singly) and cause specific mortality outcomes.
Data extraction
Data were extracted by two independent investigators, and a consensus was reached with involvement of a third. Study specific relative risks from 73 cohort studies (849 412 participants) and 22 randomised controlled trials (vitamin D given alone versus placebo or no treatment; 30 716 participants) were meta-analysed using random effects models and were grouped by study and population characteristics.
Results
In the primary prevention observational studies, comparing bottom versus top thirds of baseline circulating 25-hydroxyvitamin D distribution, pooled relative risks were 1.35 (95% confidence interval 1.13 to 1.61) for death from cardiovascular disease, 1.14 (1.01 to 1.29) for death from cancer, 1.30 (1.07 to 1.59) for non-vascular, non-cancer death, and 1.35 (1.22 to 1.49) for all cause mortality. Subgroup analyses in the observational studies indicated that risk of mortality was significantly higher in studies with lower baseline use of vitamin D supplements<SUB>.</SUB> In randomised controlled trials, relative risks for all cause mortality were 0.89 (0.80 to 0.99) for vitamin D<SUB>3</SUB> supplementation and 1.04 (0.97 to 1.11) for vitamin D<SUB>2</SUB> supplementation<SUB>.</SUB> The effects observed for vitamin D<SUB>3</SUB> supplementation remained unchanged when grouped by various characteristics. However, for vitamin D<SUB>2</SUB> supplementation, increased risks of mortality were observed in studies with lower intervention doses and shorter average intervention periods.
Conclusions
Evidence from observational studies indicates inverse associations of circulating 25-hydroxyvitamin D with risks of death due to cardiovascular disease, cancer, and other causes. Supplementation with vitamin D<SUB>3</SUB> significantly reduces overall mortality among older adults; however, before any widespread supplementation, further investigations will be required to establish the optimal dose and duration and whether vitamin D<SUB>3</SUB> and D<SUB>2</SUB> have different effects on mortality risk.
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