Table 1Reporting items for nutrition-related systematic reviews (with or without meta-analyses)

Reporting ItemDefinition for Adequate ReportingRationale for Inclusion
Search termsKeywords for identifying relevant studies for the research questions (i.e., PI(E)COS), or complete search strategy (e.g., keywords, medical subject headings) were described or referred to elsewhere.In QUOROM and MOOSE
Searches in multiple databasesSearch was conducted in more than one electronic database.In QUOROM and MOOSE
Search yearsTime period of the articles searched and included was described.In QUOROM and MOOSE
Searches in multiple languagesSearch was conducted in English and other languages.In QUOROM and MOOSE
Searching for unpublished dataAuthors explicitly stated the efforts to include unpublished data (e.g., contact with authors, meeting abstracts or conference preceding, dissertations, or grey literature search).In QUOROM and MOOSE
Inclusion or exclusion criteriaDefinitions of at least two of the PI(E)COS criteria (e.g., randomized controlled trials of the vitamin E were included) were reported.In QUOROM and MOOSE
Baseline nutrition status of the populationNutrition status of the population at baseline (i.e., malnutrition, normal, or mixed). Acceptable data include data from nutrition assessments, explicit interpretations or discussions of the nutrition status of the locations where the study were conducted, and inclusion/exclusion criterion for the nutrition status of the study population.Malnutrition is associated with vitamins and/or mineral deficiencies. Under- or over-nutrition is associated with mechanisms that affect health outcomes (14). Therefore, baseline nutrition status is an important covariate in any studies concerning the associations between micronutrients and health.
Types of interventions/exposuresNutrient interventions or exposures were described (must include dose/level and type).In QUOROM and MOOSE
Types of comparatorsComparators were described (must include dose/level and type).In QUOROM and MOOSE
Types of outcomesOutcomes or endpoints were defined.In QUOROM and MOOSE
Types of study designsDesign of the included studies was described.In QUOROM
Number of included and excluded studiesNumber of eligible and ineligible studies identified from the search was reported.In QUOROM
Reasons for exclusionReasons for exclusions were described.In QUOROM and MOOSE
Use of specific checklist for quality itemsThe list of quality items for the validity (or quality) assessment of studies were applied and reported for each included studyIn QUOROM and MOOSE
Overall rating of the study givenA overall rating of study quality was assessed (e.g. A, B, C or Good, Fair, Poor)In QUOROM and MOOSE
Models for meta- analyses*The methods of combining estimates (e.g., fixed- and random-effects models) were reported.In QUOROM and MOOSE
Assessment for heterogeneityHeterogeneity across studies was assessed (i.e., statistical methods) or discussed (i.e., qualitative analyses).In QUOROM and MOOSE
Dose-response relationship of the nutrient-outcome associations/effectsDose-response relationships were examined using dose-response statistical models, meta-regression, or subgroup analyses by different doses (i.e., quantitative assessments), or examined qualitatively (i.e. discussions).In MOOSE
Assessment of publication biasQuantitative assessment of publication bias (e.g., funnel plot, Begg and Egger tests) was used.In QUOROM and MOOSE
Discussion of publication biasIssue of publication bias was raised in Discussion.In MOOSE
Data sufficient to calculate the effect size*Data needed to calculate the effect size (e.g., 2×2 table, or mean change within group) for each study were presented in the tables or figures.In QUOROM and MOOSE
Flow diagram for the number of included and excluded studiesA flow diagram showing the progress of study selection was presented.In QUOROM
The total number of primary studies included in the systematic review/meta-analysisThe total number of studies that met inclusion criteria was reported in the text, tables, or figures.In QOUROM and MOOSE
Graphical presentation of the resultsGraphics summarizing individual study estimates and overall estimates were presented.In MOOSE
Strength (e.g. effect size) of nutrient-outcome associations/effectsThe principle measures of effect (e.g., relative risk, odds ratio, risk difference, or absolute difference) were reported.In QUOROM and MOOSE
Uncertainty of nutrient-outcome associations/effectsIndication of statistical uncertainty of findings (e.g., confidence interval), and/or description on the ranges of estimates (e.g., SD) was reported.In QOUROM and MOOSE
Analysis (qualitatively or quantitatively) for potential confounding or interactions of the nutrient-outcome associationAssessment of confounding and/or interactions (e.g., comparability of study groups) was reported, or analyzing crude and adjusted effect sizes separately.In MOOSE
Specific future research recommendationsSpecific suggestions for future research agenda (i.e., other than “"more future research is needed")In QUOROM and MOOSE
Reporting Items for nutrition-related systematic reviews that included intervention studies
Sources of the nutrient interventionsBrand names or components (or formulation) of the nutrient supplements, or foods (or recipes) in the nutrition interventions were reported.Different forms of nutrients (e.g., all-race-α-tocopherol (chemically synthesized form), RRR-α-tocopherol (naturally occurring form), or γ-tocopherol) may have different health benefits and/or bioavailability in the body.
Doses of the nutrient interventionsThe amount of nutrients (or the doses) in the interventions and intervention regimens (e.g., the number of times per day) were reported.High dose of nutrient supplementations may have harmful health effect (15). Also, the dose is necessary to understand what the intervention was.
Baseline nutrient exposures in the study populationBaseline nutrient exposures or the background diet (i.e., baseline dietary intake levels or the levels of the biomarker of intakes) in the study population were reported.Data suggest differential effects of nutrient supplementations on the prevention of chronic diseases depending on the background nutrient exposures (16–19).
Reporting Items for nutrition-related systematic reviews included observational studies
Methods/instruments for assessing intakes of nutrient exposuresMethods or instruments for assessing intakes of nutrient exposures (i.e., dietary assessments (FFQ, 24-hour recall, diet record, or diet recall) and/or biomarkers of intakes) were reported.There are known errors associated with different methods or instruments for assessing dietary intakes. The ideal method or instrument for assessing intakes of nutrient exposures depends on the research question being asked.
Ranges or distributions of the nutrient exposuresRanges or distributions of the nutrient exposures (i.e., quartiles, mean and SD, or ranges) in the study population were reported.Ranges or distributions of the nutrient exposures represent the ranges of “doses” of the nutrients in relation to the health outcomes.
Errors in assessing nutrient exposuresMeasurement errors of the dietary assessments or biomarkers of intakes were reported or discussed.Dietary intake cannot be estimated without errors. Some of these errors can be dealt with by analytical techniques (20). Some of these errors can introduce biases.
Potential impacts of the errors from assessing the nutrient exposures on the nutrient-outcome associationPotential impacts of the errors from assessing the nutrient exposures on the nutrient-outcome association were reported or discussed.The impact of particular type of errors in measuring the nutrient exposures depends on the research question being asked and the analytical methodology used to address it (21).

PI(E)COS, Population, Intervention, Exposure, Comparator, Outcome, and Study design; QUOROM, Quality Of Reporting Of Meta-analyses; MOOSE, Meta-analysis of Observational Studies in Epidemiology; FFQ, food frequency questionnaire; SD, standard deviation

*

Data were collected for systematic reviews with meta-analyses only

From: 2, Methods

Cover of Reporting of Systematic Reviews of Micronutrients and Health: A Critical Appraisal
Reporting of Systematic Reviews of Micronutrients and Health: A Critical Appraisal: Nutrition Research Series, Vol. 3.
Technical Reviews, No. 17.3.
Chung M, Balk EM, Ip S, et al.

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