| Item No | Recommendation | Page No |
Title and abstract | 1 | (a) Indicate the study’s design with a commonly used term in the title or the abstract | 1 |
(b) Provide in the abstract an informative and balanced summary of what was done and what was found | 2 | ||
Introduction | |||
Background/ rationale | 2 | Explain the scientific background and rationale for the investigation being reported | 3 |
Objectives | 3 | State specific objectives, including any prespecified hypotheses | 3, 4 |
Methods | |||
Study design | 4 | Present key elements of study design early in the paper | 4, 5 |
Setting | 5 | Describe the setting, locations, and relevant dates, including periods of recruitment, exposure, follow-up, and data collection | 4, 5 |
Participants | 6 | (a) Cohort study—Give the eligibility criteria, and the sources and methods of selection of participants. Describe methods of follow-up Case-control study—Give the eligibility criteria, and the sources and methods of case ascertainment and control selection. Give the rationale for the choice of cases and controls Cross-sectional study—Give the eligibility criteria, and the sources and methods of selection of participants | 4, 5 |
(b) Cohort study—For matched studies, give matching criteria and number of exposed and unexposed Case-control study—For matched studies, give matching criteria and the number of controls per case |
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Variables | 7 | Clearly define all outcomes, exposures, predictors, potential confounders, and effect modifiers. Give diagnostic criteria, if applicable | 5 |
Data sources/ measurement | 8* | For each variable of interest, give sources of data and details of methods of assessment (measurement). Describe comparability of assessment methods if there is more than one group | 4 |
Bias | 9 | Describe any efforts to address potential sources of bias | 7 |
Study size | 10 | Explain how the study size was arrived at | 4 |
Quantitative variables | 11 | Explain how quantitative variables were handled in the analyses. If applicable, describe which groupings were chosen and why | 4, 5 |
Statistical methods | 12 | (a) Describe all statistical methods, including those used to control for confounding | 4, 5 |
(b) Describe any methods used to examine subgroups and interactions | 4, 5 | ||
(c) Explain how missing data were addressed | 4, 5 | ||
(d) Cohort study—If applicable, explain how loss to follow-up was addressed Case-control study—If applicable, explain how matching of cases and controls was addressed Cross-sectional study—If applicable, describe analytical methods taking account of sampling strategy | 4, 5 | ||
(e) Describe any sensitivity analyses |
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Results | |||
Participants | 13* | (a) Report numbers of individuals at each stage of study—e.g. numbers potentially eligible, examined for eligibility, confirmed eligible, included in the study, completing follow-up, and analyzed | 5, 6 |
(b) Give reasons for non-participation at each stage | 5, 6 | ||
(c) Consider use of a flow diagram | 5, 6 | ||
Descriptive data | 14* | (a) Give characteristics of study participants (e.g. demographic, clinical, social) and information on exposures and potential confounders | 5, 6 |
(b) Indicate number of participants with missing data for each variable of interest | 5, 6 | ||
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| (c) Cohort study—Summarize follow-up time (e.g., average and total amount) | 5, 6 |
Outcome data | 15* | Cohort study—Report numbers of outcome events or summary measures over time | 5, 6 |
Case-control study—Report numbers in each exposure category, or summary measures of exposure |
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Cross-sectional study—Report numbers of outcome events or summary measures |
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Main results | 16 | (a) Give unadjusted estimates and, if applicable, confounder-adjusted estimates and their precision (e.g., 95% confidence interval). Make clear which confounders were adjusted for and why they were included | 5, 6 |
(b) Report category boundaries when continuous variables were categorized | 5, 6 | ||
(c) If relevant, consider translating estimates of relative risk into absolute risk for a meaningful time period |
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Other analyses | 17 | Report other analyses done—e.g. analyses of subgroups and interactions, and sensitivity analyses | 5, 6 |
Discussion | |||
Key results | 18 | Summarize key results with reference to study objectives | 6, 7 |
Limitations | 19 | Discuss limitations of the study, taking into account sources of potential bias or imprecision. Discuss both direction and magnitude of any potential bias | 7 |
Interpretation | 20 | Give a cautious overall interpretation of results considering objectives, limitations, multiplicity of analyses, results from similar studies, and other relevant evidence | 6, 7 |
Generalizability | 21 | Discuss the generalizability (external validity) of the study results | 7, 8 |
Other information | |||
Funding | 22 | Give the source of funding and the role of the funders for the present study and, if applicable, for the original study on which the present article is based | 1, 7 |