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Cochrane Database of Systematic Reviews

Zinc supplementation for the prevention of type 2 diabetes mellitus in adults with insulin resistance

Information

DOI:
https://doi.org/10.1002/14651858.CD005525.pub3Copy DOI
Database:
  1. Cochrane Database of Systematic Reviews
Version published:
  1. 28 May 2015see what's new
Type:
  1. Intervention
Stage:
  1. Review
Cochrane Editorial Group:
  1. Cochrane Metabolic and Endocrine Disorders Group

Copyright:
  1. Copyright © 2015 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.

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Authors

  • Regina El Dib

    Correspondence to: Department of Anaesthesiology, Botucatu Medical School, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil

    [email protected]

    [email protected]

  • Orsi LF Gameiro

    Reabilitation Service, Universidade Estadual Paulista (UNESP), Botucatu, Brazil

  • Matheus SP Ogata

    Department of Anaesthesiology, Botucatu Medical School, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil

  • Norma SP Módolo

    Department of Anaesthesiology, Botucatu Medical School, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil

  • Leandro G Braz

    Department of Anaesthesiology, Botucatu Medical School, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil

  • Eliane C Jorge

    Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Botucatu Medical School, Universidade Estadual Paulista (UNESP), Botucatu, Brazil

  • Paulo do Nascimento Junior

    Department of Anaesthesiology, Botucatu Medical School, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil

  • Vânia Beletate

    Clinical Nutrition, University of São Camilo, Piraciacaba SP, Brazil

Contributions of authors

Regina El Dib (RED): co‐ordinating the review, data management, interpretation of data, writing the review, securing funding for the review, guarantor for the review, responsible for reading and checking the review before submission.

Luis Felipe Orsi Gameiro (LFOG): undertaking manual searches, screening search results, organising retrieval of publications, screening retrieved publications against inclusion criteria, appraising quality of publications, abstracting data from publications, obtaining and screening data on unpublished studies, data management for the review, entering data into Review Manager, double entry of data.

Matheus SP Ogata (MSPO): providing additional data about publications, abstracting data from publications, obtaining and screening data on unpublished studies, entering data into Review Manager, double entry of data.

Norma SP Módolo (NSPM): responsible for reading and checking the review before submission.

Leandro G Braz (LGB): responsible for reading and checking the review before submission.

Eliane C Jorge: responsible for reading and checking the review before submission.

Paulo do Nascimento Junior (PNJ): responsible for reading and checking the review before submission.

Vânia Beletate (VB): conceiving the review.

Sources of support

Internal sources

  • Brazilian Cochrane Center, Brazil.

External sources

  • No sources of support supplied

Declarations of interest

RED: none known.

LFOG: none known.

MSPO: none known.

NSPM: none known.

LGB: none known.

ECJ: none known.

PNJ: none known.

VB: none known.

Acknowledgements

The authors would like to thank Regis Bruni Andriolo for his useful advice in the development of the original review. We also would like to thank Karla Bergerhoff and Maria‐Inti Metzendorf for the searches done for this review update. We also are thankful for Dr. Esperanza Martínez‐Abundis and Dr. Gómez‐García who provided us with further information and details of their publications.

Version history

Published

Title

Stage

Authors

Version

2015 May 28

Zinc supplementation for the prevention of type 2 diabetes mellitus in adults with insulin resistance

Review

Regina El Dib, Orsi LF Gameiro, Matheus SP Ogata, Norma SP Módolo, Leandro G Braz, Eliane C Jorge, Paulo do Nascimento Junior, Vânia Beletate

https://doi.org/10.1002/14651858.CD005525.pub3

2007 Jan 24

Zinc supplementation for the prevention of type 2 diabetes mellitus

Review

Vânia Beletate, Regina El Dib, Álvaro N Atallah

https://doi.org/10.1002/14651858.CD005525.pub2

2005 Oct 19

Zinc supplementation for the prevention of type 2 diabetes mellitus

Protocol

Vânia Beletate, Álvaro N Atallah, Regina P El Dib

https://doi.org/10.1002/14651858.CD005525

Differences between protocol and review

This review is an update of the previous Cochrane systematic review, which included one RCT (Beletate 2007).

The previous author Álvaro Atallah decided not to participate in the update of the review. For this update the following new authors contributed: Luis Felipe Orsi Gameiro, Matheus Senna Pereira Ogata, Norma Sueli Pinheiro Modolo, Leandro Gobbo Braz, Eliane C Jorge and Paulo do Nascimento Junior.

We updated the Methods section (added the 'Summary of findings' table and the new 'Risk of bias' assessment). We changed adverse events from a secondary to a primary outcome measure.

Keywords

MeSH

PICOs

Population
Intervention
Comparison
Outcome

The PICO model is widely used and taught in evidence-based health care as a strategy for formulating questions and search strategies and for characterizing clinical studies or meta-analyses. PICO stands for four different potential components of a clinical question: Patient, Population or Problem; Intervention; Comparison; Outcome.

See more on using PICO in the Cochrane Handbook.

Study flow diagram.
Figures and Tables -
Figure 1

Study flow diagram.

'Risk of bias' graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
Figures and Tables -
Figure 2

'Risk of bias' graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study.
Figures and Tables -
Figure 3

'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study.

Comparison 1 Zinc supplementation versus placebo, Outcome 1 HOMA‐IR.
Figures and Tables -
Analysis 1.1

Comparison 1 Zinc supplementation versus placebo, Outcome 1 HOMA‐IR.

Comparison 1 Zinc supplementation versus placebo, Outcome 2 Lipids.
Figures and Tables -
Analysis 1.2

Comparison 1 Zinc supplementation versus placebo, Outcome 2 Lipids.

Comparison 2 Zinc supplementation versus exercise, Outcome 1 HOMA‐IR.
Figures and Tables -
Analysis 2.1

Comparison 2 Zinc supplementation versus exercise, Outcome 1 HOMA‐IR.

Comparison 2 Zinc supplementation versus exercise, Outcome 2 Lipids.
Figures and Tables -
Analysis 2.2

Comparison 2 Zinc supplementation versus exercise, Outcome 2 Lipids.

Zinc supplementation for the prevention of type 2 diabetes mellitus

Population: non‐diabetic adults with insulin resistance

Settings: not specified/outpatients

Intervention: zinc supplementation

Comparison: placebo or exercise

Outcomes

Illustrative comparative risks* (95% CI)

Relative effect
(95% CI)

No of participants
(studies)

Quality of the evidence
(GRADE)

Comments

Assumed risk

Corresponding risk

Placebo or exercise

Zinc supplementation

Incidence of type 2 diabetes mellitus

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Outcome not reported

Diabetic complications

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Outcome not reported

Adverse events

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Outcome not reported

Health‐related quality of life

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Outcome not reported

All‐cause mortality

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Outcome not reported

Socioeconomic effects

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Outcome not reported

*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: confidence interval

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

Figures and Tables -
Table 1. Overview of study populations

Intervention(s) and comparator(s)

Sample sizea

Screened/eligible
[N]

Randomised
[N]

ITT
[N]

Analysed
[N]

Finishing study
[N]

Randomised finishing study
[%]

Follow‐up timeb

(1) Gómez‐García 2006

I: 100 mg/day zinc sulfate

12
(6 participants per group; 80% power)

14

7

7

7

100

1 month

C: placebo

7

7

7

100

total:

14

14

14

100

(2) Marreiro 2006

I: 30 mg/day zinc amino chelate

28

28

28

100

1 month

C: placebo

28

28

28

100

total:

56

56

56

100

(3) Soheilykhah 2012

I: 50 mg/day zinc sulfate

28

28

100

12 weeks

C: regular exercise and weight control

25

25

100

total:

58

53

53

91.4

Grand total

All interventions

63

63

All comparators

60

60

All interventions and comparators

128

123

aAccording to power calculation in study publication or report
bDuration of intervention and/or follow‐up under randomised conditions until end of study

"‐" denotes not reported

C: comparator; I: intervention; ITT: intention‐to‐treat.

Figures and Tables -
Table 1. Overview of study populations
Comparison 1. Zinc supplementation versus placebo

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 HOMA‐IR Show forest plot

1

Mean Difference (IV, Fixed, 95% CI)

Totals not selected

1.1 HOMA‐IR

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2 Lipids Show forest plot

2

Mean Difference (IV, Fixed, 95% CI)

Totals not selected

2.1 Total cholesterol

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.2 Total cholesterol

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.3 HDL cholesterol

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.4 HDL cholesterol

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.5 LDL cholesterol

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.6 LDL cholesterol

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.7 VLDL cholesterol

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.8 VLDL lipoprotein

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.9 Triglycerides

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.10 Triglycerides 

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

Figures and Tables -
Comparison 1. Zinc supplementation versus placebo
Comparison 2. Zinc supplementation versus exercise

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 HOMA‐IR Show forest plot

1

Mean Difference (IV, Fixed, 95% CI)

Totals not selected

2 Lipids Show forest plot

1

Mean Difference (IV, Fixed, 95% CI)

Totals not selected

2.1 Total cholesterol

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.2 HDL cholesterol

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.3 LDL cholesterol

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.4 Triglycerides

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

Figures and Tables -
Comparison 2. Zinc supplementation versus exercise