Online supplemental material 1

Meta-analysis of Observational Studies in Epidemiology (MOOSE) Checklist

Criteria / Brief description of how the criteria were handled in the meta-analysis
Reporting of background should include
Problem definition / Tea is the second most popularbeverage in the world. It originates from the leaves of the plant Camellia sinensis. Of the total amount of tea consumed in the world, 20% is green tea (unfermented) ,78% is black tea (fermented) and 2% is oolong tea (partially fermented). Several studies assessing green tea and black tea consumption with the risk of endometrial cancer (EC) have yielded inconsistent results
Hypothesis statement / Green tea and black tea mightinfluence the risk of EC.
Description of study outcomes / Risk of EC
Type of exposure or intervention used / Green tea and black tea consumption
Type of study designs used / We included case-control studies, cohort studies.
Study population / We placed no restriction.
Reporting of search strategy should include
Qualifications of searchers / The credentials of the two investigators QZ and HL are indicated in the author list.
Search strategy, including time period included in the synthesis and keywords / We searched PubMed, Embase, Cochrane Library and China Biological Medicine Database from inception to February 2, 2015. The following keywords were used in our search strategies: ("endometrial cancer" OR "endometrium cancer" OR "endometrial carcinoma" OR "endometrium carcinoma" OR "endometrial neoplasms" OR "endometrium neoplasms" OR "corpus uteri cancer" OR "corpus uteri neoplasm" OR "corpus uteri carcinoma" OR "uterus tumor" OR "uterine tumor") AND ("Tea" OR "green tea" OR "black tea" OR "catechin" OR "theaflavin" OR " thearubigin").
Databases and registries searched / PubMed, Embase, Cochrane Library and China Biological Medicine Database
Search software used, name and version, including special features / We did not employ any search software. EndNote was used to merge retrieved citations and eliminate duplications
Use of hand searching / We hand-searched bibliographies of retrieved papers for additional references,
List of citations located and those excluded, including justifications / Details of the literature search process are outlined in the flow chart. The citation list is available upon request
Method of addressing articles published in languages other than English / We placed no restrictions on language; The final papers are all in English and Chinese.
Method of handling abstracts and unpublished studies / No unpublished studies were observed.
Description of any contact with authors / No studies need to contact authors
Reporting of methods should include
Description of relevance or appropriateness of studies assembled for assessing the hypothesis to be tested / Detailed inclusion and exclusion criteria were described in the methods section.
Rationale for the selection and coding of data / Data extracted from each of the studies were relevant to the population characteristics, study design, exposure, outcome, and possible effect modifiers of the association.
Assessment of confounding / No restricted for the analysis. Conducted sensitivity analyses by eliminating each study.
Assessment of study quality, including blinding of quality assessors; stratification or regression on possible predictors of study results / We used the Newcastle-Ottawa Quality Assessment Scale (NOQAS) to assess the study quality of the included studies
Assessment of heterogeneity / Heterogeneity of the studies were explored within two types of study designs using Cochrane’s Q test of heterogeneity and I2 statistic that provides the relative amount of variance of the summary effect due to the between-study heterogeneity.
Description of statistical methods in sufficient detail to be replicated / Description of methods of meta-analyses, dose-response meta-analysis, sensitivity analyses and assessment of publication bias are detailed in the methods.
Provision of appropriate tables and graphics / Results
Reporting of results should include
Graph summarizing individual study estimates and overall estimate / Figure 2
Table giving descriptive information for each study included / Table 1
Results of sensitivity testing / Results
Indication of statistical uncertainty of findings / 95% confidence intervals were presented with all summary estimates. Power analyses were conducted
Reporting of discussion should include
Quantitative assessment of bias / Discussion
Justification for exclusion(eg, exclusion of non–English-language citations) / No exclusions on the basis of language ofpublication.
Assessment of quality of included studies / NOS score status can partly explainthe heterogeneity observed in the black tea and risk of EC.
Reporting of conclusions should include
Consideration of alternative explanations for observed results / Consideration of alternative explanations for observed results was discussed in the “limitations of the meta-analysis” in the discussion section
Generalization of the conclusions((ie, appropriate for the data presented and within the domain of the literature review)) / Discussion
Guidelines for future research / We recommend future studies on the associations betweenblack tea and EC.
Disclosure of funding source / This work was supported by Instructional science and technology Program of Changde City(2014ZD11), NSFC(Natural Science Foundation of China) (81360351).