Table 3 STROBE statement—checklist of items that should be included in reports of cross-sectional studies [32]

Title and abstract

(a) Indicate the study’s design with a commonly used term in the title or the abstract

2

(b) Provide in the abstract an informative and balanced summary of what was done and what was found

2

Introduction

Background/rationale

Explain the scientific background and rationale for the investigation being reported

3

Objectives

State specific objectives, including any pre-specified hypotheses

3

Methods

Study design

Present key elements of study design early in the paper

4

Setting

Describe the setting, locations, and relevant dates, including periods of recruitment, exposure, follow-up, and data collection

4

Participants

(a) Give the eligibility criteria and the sources and methods of selection of participants

4

Variables

Clearly define all outcomes, exposures, predictors, potential confounders, and effect modifiers. Give diagnostic criteria, if applicable

4–5

Data sources/measurement

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

Describe any efforts to address potential sources of bias

–

Study size

Explain how the study size was arrived at

4–5

Quantitative variables

Explain how quantitative variables were handled in the analyses. If applicable, describe which groupings were chosen and why

4–5

Statistical methods

(a) Describe all statistical methods, including those used to control for confounding

5

(b) Describe any methods used to examine subgroups and interactions

5

(c) Explain how missing data were addressed

5

(d) If applicable, describe analytical methods taking account of sampling strategy

5

(e) Describe any sensitivity analyses

5

Results

Participants

(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

7

(b) Give reasons for non-participation at each stage

4–5

(c) Consider use of a flow diagram

–

Descriptive data

(a) Give characteristics of study participants (e.g., demographic, clinical, social) and information on exposures and potential confounders

6

(b) Indicate number of participants with missing data for each variable of interest

–

Outcome data

Report numbers of outcome events or summary measures

6

Main results

(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

6

(b) Report category boundaries when continuous variables were categorized

6

(c) If relevant, consider translating estimates of relative risk into absolute risk for a meaningful time period

6

Other analyses

Report other analyses done—e.g., analyses of subgroups and interactions, and sensitivity analyses

6

Discussion

Key results

Summarize key results with reference to study objectives

7

Limitations

Discuss limitations of the study, taking into account sources of potential bias or imprecision. Discuss both direction and magnitude of any potential bias

–

Interpretation

Give a cautious overall interpretation of results considering objectives, limitations, multiplicity of analyses, results from similar studies, and other relevant evidence

7–8

Generalizability

Discuss the generalizability (external validity) of the study results

7–8

Other information

Funding

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

09