| Title and abstract |
1 |
(a) Indicate the study’s design with a commonly used term in the title or the abstract |
|
| (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 |
2,3 |
| Objectives |
3 |
State specific objectives, including any prespecified hypotheses |
3 |
| Methods |
|
| Study design |
4 |
Present key elements of study design early in the paper |
3 |
| Setting |
5 |
Describe the setting, locations, and relevant dates, including periods of recruitment, exposure, follow-up, and data collection |
3,4,5 |
| 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 |
3 |
|
(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 |
3 |
| 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 |
5 |
| Bias |
9 |
Describe any efforts to address potential sources of bias |
3,5 |
| Study size |
10 |
Explain how the study size was arrived at |
n/a |
| Quantitative variables |
11 |
Explain how quantitative variables were handled in the analyses. If applicable, describe which groupings were chosen and why |
5 |
| Statistical methods |
12 |
(a) Describe all statistical methods, including those used to control for confounding |
5,6 |
|
(b) Describe any methods used to examine subgroups and interactions |
n/a |
|
(c) Explain how missing data were addressed |
n/a |
|
(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 |
n/a |
|
|
(e) Describe any sensitivity analyses |
5 |
| Results |
|
| Participants |
13* |
(a) Report numbers of individuals at each stage of study—eg numbers potentially eligible, examined for eligibility, confirmed eligible, included in the study, completing follow-up, and analysed |
4,6 |
| (b) Give reasons for non-participation at each stage |
4 |
| (c) Consider use of a flow diagram |
4 |
| Descriptive data |
14* |
(a) Give characteristics of study participants (eg demographic, clinical, social) and information on exposures and potential confounders |
6,7 |
| (b) Indicate number of participants with missing data for each variable of interest |
n/a |
| (c) Cohort study—Summarise follow-up time (eg, average and total amount) |
|
| Outcome data |
15* |
Cohort study—Report numbers of outcome events or summary measures over time |
|
Case-control study—Report numbers in each exposure category, or summary measures of exposure |
6-12 |
|
Cross-sectional study—Report numbers of outcome events or summary measures |
|
| Main results |
16 |
(a) Give unadjusted estimates and, if applicable, confounder-adjusted estimates and their precision (eg, 95% confidence interval). Make clear which confounders were adjusted for and why they were included |
6-12 |
| (b) Report category boundaries when continuous variables were categorized 6-12 |
n/a |
| (c) If relevant, consider translating estimates of relative risk into absolute risk for a meaningful time period n/3 |
n/a |
| Other analyses |
17 |
Report other analyses done—eg analyses of subgroups and interactions, and sensitivity analyses |
| Discussion |
|
| Key results |
18 |
Summarise key results with reference to study objectives |
15 |
| 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 |
13,14,15 |
| Interpretation |
20 |
Give a cautious overall interpretation of results considering objectives, limitations, multiplicity of analyses, results from similar studies, and other relevant evidence |
|
| Generalisability |
21 |
Discuss the generalisability (external validity) of the study results n/3 |
n/a |
| Other information |
|
| Funding |
2222 |
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 |
1,16 |