Reviewer's report
Title:Physical Activity is Associated with Reduced Risk of Esophageal Cancer,
Particularly Esophageal Adenocarcinoma: A Systematic Review and
Meta-Analysis
Version:2Date:10 April 2014
Reviewer: Michael Leitzmann
Reviewer's report:
Major essential revisions:
One potential concern is that the current analysis principally focusses on EAC
and provides virtually no data on ESCC. Could you possibly have missed some
studies on physical activity and ESCC risk? Related to this, your literature review
was conducted over a year ago and may therefore not be current. For example, a
study by Dar et al. on occupational physical activity and ESCC was published in
September 2013 and should probably have been included in the meta-analysis.
The abstract states that physical activity may modify the effect of obesity on risk
for EAC. However, the manuscript did not address that specific question, so I
recommend removing that statement.
The Methods section states that effect estimates were pooled using a fixed
effects model if a study reported on more than one physical activity domain.
Please ensure that the assumption for that model was not violated (i.e., there
was no heterogeneity of effect estimates in the underlying studies).
The results section states that results remained statistically significant on
restricting analysis to high-quality studies. However, the upper limit of the 95%
confidence interval is 1.0 and therefore lacks formal statistical significance.
Minor essential revisions:
Reference number 34 contains typos in the author list.
The name of the author Huerta et al. is misspelled in the Tables and Figures.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a statistician.
Declaration of competing interests:
I declare that I have no competing interests.
Reviewer's report
Title:Physical Activity is Associated with Reduced Risk of Esophageal Cancer,
Particularly Esophageal Adenocarcinoma: A Systematic Review and
Meta-Analysis
Version:2Date:10 April 2014
Reviewer: Michael Leitzmann
Reviewer's report:
Major essential revisions:
One potential concern is that the current analysis principally focusses on EAC
and provides virtually no data on ESCC. Could you possibly have missed some
studies on physical activity and ESCC risk? Related to this, your literature review
was conducted over a year ago and may therefore not be current. For example, a
study by Dar et al. on occupational physical activity and ESCC was published in
September 2013 and should probably have been included in the meta-analysis.
The abstract states that physical activity may modify the effect of obesity on risk
for EAC. However, the manuscript did not address that specific question, so I
recommend removing that statement.
The Methods section states that effect estimates were pooled using a fixed
effects model if a study reported on more than one physical activity domain.
Please ensure that the assumption for that model was not violated (i.e., there
was no heterogeneity of effect estimates in the underlying studies).
The results section states that results remained statistically significant on
restricting analysis to high-quality studies. However, the upper limit of the 95%
confidence interval is 1.0 and therefore lacks formal statistical significance.
Minor essential revisions:
Reference number 34 contains typos in the author list.
The name of the author Huerta et al. is misspelled in the Tables and Figures.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a statistician.
Declaration of competing interests:
I declare that I have no competing interests.
Please review this paper.
user
Reviewer's report
Title:Physical Activity is Associated with Reduced Risk of Esophageal Cancer,
Particularly Esophageal Adenocarcinoma: A Systematic Review and
Meta-Analysis
Version:2Date:10 April 2014
Reviewer: Michael Leitzmann
Reviewer's report:
Major essential revisions:
One potential concern is that the current analysis principally focusses on EAC
and provides virtually no data on ESCC. Could you possibly have missed some
studies on physical activity and ESCC risk? Related to this, your literature review
was conducted over a year ago and may therefore not be current. For example, a
study by Dar et al. on occupational physical activity and ESCC was published in
September 2013 and should probably have been included in the meta-analysis.
The abstract states that physical activity may modify the effect of obesity on risk
for EAC. However, the manuscript did not address that specific question, so I
recommend removing that statement.
The Methods section states that effect estimates were pooled using a fixed
effects model if a study reported on more than one physical activity domain.
Please ensure that the assumption for that model was not violated (i.e., there
was no heterogeneity of effect estimates in the underlying studies).
The results section states that results remained statistically significant on
restricting analysis to high-quality studies. However, the upper limit of the 95%
confidence interval is 1.0 and therefore lacks formal statistical significance.
Minor essential revisions:
Reference number 34 contains typos in the author list.
The name of the author Huerta et al. is misspelled in the Tables and Figures.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a statistician.
Declaration of competing interests:
I declare that I have no competing interests.
assistant