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纳入研究16篇文献的质量评价（STROBE声明）

STROBE statement-checklist criteria included in 16 reports of passive smoking and lung cancer risk

Items	Recommendation	Number of stydy [n (%)]
Title and abstract	1.1 Indicate the study’s design with a commonly used term in the title or the abstract	6 (27.3%)
	1.2 Provide in the abstract an informative and balanced summary of what was done and what was found	16 (72.7%)
Introduction
Background/rationale	2 Explain the scientific background and rationale for the investigation being reported	17 (77.3%)
Objectives	3 State specific objectives, including any prespecified hypotheses	18 (81.8%)
Methods
Study desin	4 Present key elemens of study design early in the paper	15 (68.2%)
Setting	5 Describe the setting, locations, and relevant dates, including periods of recruitment, exposure, follow-up, and data collection	20 (90.9%)
Participants	6.1 Give the eligibility criteria, and the sources and methods of ascertainment, and control selection. Give the rationale for the choice of cases and controls	11 (50.0%)
	6.2 For matched studies, give matching criteria and the number of controls per case	10 (45.5%)
Variables	7 Clearly define all outcomes, exposures, predictors, potential confounders, and effect modifiers. Give diagnostic criteria, if applicable	10 (45.5%)
Datasources/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	12 (54.5%)
Bias	9 Describe any efforts to address potential sources of bias	3 (13.6%)
Study size	10 Explain how the study size was arrived at	0 (0)
Quantitative variables	11 Explain how quantitative variables were handled in the analyses. If applicable, describe which groupings were chosen and why	11 (50.0%)
Statistical methods	12.1 Describe all statistical methods, including those used to control for confounding	16 (72.7%)
	12.2 Describe any methods used to examine subgroups and interactions	14 (63.6%)
	12.3 Explain how missing data were addressed	9 (40.9%)
	12.4 If applicable, explain how matching of cases and controls was addressed 12.5 Describe any sensitivity analyses	11 (50.0%)
Results
Participants	13.1 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)	16 (72.7%)
	13.2 Give reasons for non-participation at each stage	8 (36.4%)
	13.3 Consider use of a flow diagram	2 (9.1%)
Descriptive data	14.1 Give characteristics of study participants (eg demographic, clinical, social) and information on exposures and potential confounders	13 (59.1)
	14.2 Indicate number of participants with missing data for each variable of interest	9 (40.9%)
Outcome data	15 Report numbers in each exposure category, or summary measures of exposure	17 (77.3%)
	16.1 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	12 (54.5%)
	16.2 Report category boundaries when continuous variables were categorized	14 (63.6%)
	16.3 If relevant, consider translating estimates of relative risk into absolute risk for a meaningful time period	6 (27.3%)
Other analyses	17 Report other analyses done (eg analyses of subgroups and interactions, and sensitivity analyses)	7 (31.8%)
Discusion
Key results	18 Summarise key results with reference to study objectives	22 (100%)
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	12 (54.5%)
Interpretation	20 Give a cautious overall interpretation of results considering objectives, limitations, multiplicity of analyses, results from similar studies, and other relevant evidence	11 (50.0%)
Generalisability	21 Discuss the generalisability (external validity) of the study results	7 (12.7%)
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	9 (40.9%)