Reviewer's report
Title:Green tea consumption and risk of esophageal cancer: a meta-analysis of
epidemiologic studies
Version: 2Date:4 September 2012
Reviewer: Alessandra Tavani
Reviewer's report:
After revision the paper has greatly improved. However there is still an important
limitation. The keywords the authors used are imprecise. The term “tea” is not
enough when in a bibliographic research you need to obtain all papers.
Databases usually search keywords only in the text and not in Tables and tea
could be included in a Table together with other foods without comment in the
text, especially if it is not related to the studied disease. Thus the authors should
use “tea OR food OR diet OR beverage OR drinking…….”. Maybe they will not
find other papers, but this must be checked. Otherwise authors risk to exclude
mainly null papers, which is a big bias for a quantitative overall risk estimate of
the risk.
There are other smaller limitations which do not preclude paper publication, but
render the paper less informative than it could be:
1) As for the dose-response analyses asked by one referee, the authors say that
they could not perform the analysis because papers have used inconsistent
measures of the amount of tea consumption. This is an intrinsic limitation of all
meta-analyses. However, what it is usually done is that the authors select all
papers reporting at least 3 categories of consumption and pool their results for a
low/medium/high intake.
2) The authors should also report drinkers vs non drinkers; to obtain the category
“drinkers” they should pool within each study all categories of drinkers.
3) The sensitivity analysis has not been shown.
4) It is not indicated to which category of consumption the RR/OR refer to:
highest vs lowest in each paper? If this is the case the authors should also do
report a RR/OR estimate excluding the paper considering only drinkers vs non
drinkers.
Possibly all these suggested analyses will not change the message of the paper,
but they add much information and render the paper more methodologically
correct.
Level of interest: An article of importance in its field
Quality of written English: Needs some language corrections before being
published
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
Reviewer's report
Title:Green tea consumption and risk of esophageal cancer: a meta-analysis of
epidemiologic studies
Version: 2Date:4 September 2012
Reviewer: Alessandra Tavani
Reviewer's report:
After revision the paper has greatly improved. However there is still an important
limitation. The keywords the authors used are imprecise. The term “tea” is not
enough when in a bibliographic research you need to obtain all papers.
Databases usually search keywords only in the text and not in Tables and tea
could be included in a Table together with other foods without comment in the
text, especially if it is not related to the studied disease. Thus the authors should
use “tea OR food OR diet OR beverage OR drinking…….”. Maybe they will not
find other papers, but this must be checked. Otherwise authors risk to exclude
mainly null papers, which is a big bias for a quantitative overall risk estimate of
the risk.
There are other smaller limitations which do not preclude paper publication, but
render the paper less informative than it could be:
1) As for the dose-response analyses asked by one referee, the authors say that
they could not perform the analysis because papers have used inconsistent
measures of the amount of tea consumption. This is an intrinsic limitation of all
meta-analyses. However, what it is usually done is that the authors select all
papers reporting at least 3 categories of consumption and pool their results for a
low/medium/high intake.
2) The authors should also report drinkers vs non drinkers; to obtain the category
“drinkers” they should pool within each study all categories of drinkers.
3) The sensitivity analysis has not been shown.
4) It is not indicated to which category of consumption the RR/OR refer to:
highest vs lowest in each paper? If this is the case the authors should also do
report a RR/OR estimate excluding the paper considering only drinkers vs non
drinkers.
Possibly all these suggested analyses will not change the message of the paper,
but they add much information and render the paper more methodologically
correct.
Level of interest: An article of importance in its field
Quality of written English: Needs some language corrections before being
published
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
Please review this paper.
user
Reviewer's report
Title:Green tea consumption and risk of esophageal cancer: a meta-analysis of
epidemiologic studies
Version: 2Date:4 September 2012
Reviewer: Alessandra Tavani
Reviewer's report:
After revision the paper has greatly improved. However there is still an important
limitation. The keywords the authors used are imprecise. The term “tea” is not
enough when in a bibliographic research you need to obtain all papers.
Databases usually search keywords only in the text and not in Tables and tea
could be included in a Table together with other foods without comment in the
text, especially if it is not related to the studied disease. Thus the authors should
use “tea OR food OR diet OR beverage OR drinking…….”. Maybe they will not
find other papers, but this must be checked. Otherwise authors risk to exclude
mainly null papers, which is a big bias for a quantitative overall risk estimate of
the risk.
There are other smaller limitations which do not preclude paper publication, but
render the paper less informative than it could be:
1) As for the dose-response analyses asked by one referee, the authors say that
they could not perform the analysis because papers have used inconsistent
measures of the amount of tea consumption. This is an intrinsic limitation of all
meta-analyses. However, what it is usually done is that the authors select all
papers reporting at least 3 categories of consumption and pool their results for a
low/medium/high intake.
2) The authors should also report drinkers vs non drinkers; to obtain the category
“drinkers” they should pool within each study all categories of drinkers.
3) The sensitivity analysis has not been shown.
4) It is not indicated to which category of consumption the RR/OR refer to:
highest vs lowest in each paper? If this is the case the authors should also do
report a RR/OR estimate excluding the paper considering only drinkers vs non
drinkers.
Possibly all these suggested analyses will not change the message of the paper,
but they add much information and render the paper more methodologically
correct.
Level of interest: An article of importance in its field
Quality of written English: Needs some language corrections before being
published
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
assistant