Reviewer's report
Title:Consumption of Coffee Reduces Risk for Liver Cancer: A Meta-Analysis
Version: 2Date:16 October 2012
Reviewer: Susan Stewart
Reviewer's report:
This is well-conducted study of some interest, and the methods and interpretation
of the results are appropriate. I have only a few comments.
Minor essential revisions: Please address the following issues.
1. Materials and methods: statistical analysis
a. How were random effects models used? Were any of the pooled ORs shown
in the results section computed from random effects models?
b. The next to last sentence in the section states that p<0.05 was considered
statistically significant; however, the 4th sentence of the section states that
p<0.10 was considered statistically significant for the evaluation of heterogeneity.
For which analyses was a significance level of 0.05 used?
2. Results
a. Study characteristics: The second sentence states that there were 15 articles
(should be 16).
b. Subgroup analysis: Table 4 shows that I2 was > 50% for two of the subgroup
analyses (hospital-based case-control studies and studies unadjusted for main
confounders), indicating heterogeneity. Were the pooled ORs for these
subgroups computed using random effects models?
3. Discussion: The authors note that their results are consistent with those of a
previously published meta-analysis (Bravi et al., 2007). This is not surprising,
since the authors’ meta-analysis includes all of the studies in the previous
meta-analysis; this overlap should be noted.
Level of interest: An article whose findings are important to those with closely
related research interests
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:Consumption of Coffee Reduces Risk for Liver Cancer: A Meta-Analysis
Version: 2Date:16 October 2012
Reviewer: Susan Stewart
Reviewer's report:
This is well-conducted study of some interest, and the methods and interpretation
of the results are appropriate. I have only a few comments.
Minor essential revisions: Please address the following issues.
1. Materials and methods: statistical analysis
a. How were random effects models used? Were any of the pooled ORs shown
in the results section computed from random effects models?
b. The next to last sentence in the section states that p<0.05 was considered
statistically significant; however, the 4th sentence of the section states that
p<0.10 was considered statistically significant for the evaluation of heterogeneity.
For which analyses was a significance level of 0.05 used?
2. Results
a. Study characteristics: The second sentence states that there were 15 articles
(should be 16).
b. Subgroup analysis: Table 4 shows that I2 was > 50% for two of the subgroup
analyses (hospital-based case-control studies and studies unadjusted for main
confounders), indicating heterogeneity. Were the pooled ORs for these
subgroups computed using random effects models?
3. Discussion: The authors note that their results are consistent with those of a
previously published meta-analysis (Bravi et al., 2007). This is not surprising,
since the authors’ meta-analysis includes all of the studies in the previous
meta-analysis; this overlap should be noted.
Level of interest: An article whose findings are important to those with closely
related research interests
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:Consumption of Coffee Reduces Risk for Liver Cancer: A Meta-Analysis
Version: 2Date:16 October 2012
Reviewer: Susan Stewart
Reviewer's report:
This is well-conducted study of some interest, and the methods and interpretation
of the results are appropriate. I have only a few comments.
Minor essential revisions: Please address the following issues.
1. Materials and methods: statistical analysis
a. How were random effects models used? Were any of the pooled ORs shown
in the results section computed from random effects models?
b. The next to last sentence in the section states that p<0.05 was considered
statistically significant; however, the 4th sentence of the section states that
p<0.10 was considered statistically significant for the evaluation of heterogeneity.
For which analyses was a significance level of 0.05 used?
2. Results
a. Study characteristics: The second sentence states that there were 15 articles
(should be 16).
b. Subgroup analysis: Table 4 shows that I2 was > 50% for two of the subgroup
analyses (hospital-based case-control studies and studies unadjusted for main
confounders), indicating heterogeneity. Were the pooled ORs for these
subgroups computed using random effects models?
3. Discussion: The authors note that their results are consistent with those of a
previously published meta-analysis (Bravi et al., 2007). This is not surprising,
since the authors’ meta-analysis includes all of the studies in the previous
meta-analysis; this overlap should be noted.
Level of interest: An article whose findings are important to those with closely
related research interests
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