Reviewer's report
Title:Associations of Coffee Consumption with Markers of Liver Injury in the
Insulin Resistance Atherosclerosis Study
Version:2Date:27 February 2015
Reviewer: Ran Jin
Reviewer's report:
Dickson et al. identified significant inverse associations of caffeinated coffee
consumption with ALT, AST, and the NAFLD liver fat score, suggesting a
beneficial impact of caffeinated coffee consumption on liver-related outcomes.
Generally, this is a well-organized and well-written manuscript of important
interest in the related research field. The authors have clearly stated the current
knowledge gaps and posed their research questions, also the methods are
sufficiently provided to support their findings. I am very pleased to review this
work and following are my comments and suggestions. The authors have
adjusted several clusters of potential confounds in the linear regression models
aiming to analyze an independent relationship between coffee consumption and
the liver health. I am not surprised that the observed associations were
attenuated by controlling for insulin sensitivity given the fact that fatty liver and
impaired insulin sensitivity are highly correlated. It is very critical to adjust dietary
factors as the authors did in model 3, but my major concern is sugar
consumption (primarily fructose) should be also controlled as a confounder. Tons
of evidence has proposed fructose (e.g. from sugar-sweetened beverages) as a
culprit of NAFLD. It could be that habitually higher coffee consumers are more
likely to have less sugar-sweetened drinks which could be an underlying link for
the authors’ reported inverse associations in this study. It will be more convincing
to me if the sugar adjustment could be performed, so I will take this as a request
for major compulsory revisions. In addition, a minor concern is although the
reported inverse associations are statistically significant, correlation coefficients
are small numbers (almost > - 0.1 for all) thus how important it will be in the
biological nature?
Level of interest: An article of importance in its field
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:Associations of Coffee Consumption with Markers of Liver Injury in the
Insulin Resistance Atherosclerosis Study
Version:2Date:27 February 2015
Reviewer: Ran Jin
Reviewer's report:
Dickson et al. identified significant inverse associations of caffeinated coffee
consumption with ALT, AST, and the NAFLD liver fat score, suggesting a
beneficial impact of caffeinated coffee consumption on liver-related outcomes.
Generally, this is a well-organized and well-written manuscript of important
interest in the related research field. The authors have clearly stated the current
knowledge gaps and posed their research questions, also the methods are
sufficiently provided to support their findings. I am very pleased to review this
work and following are my comments and suggestions. The authors have
adjusted several clusters of potential confounds in the linear regression models
aiming to analyze an independent relationship between coffee consumption and
the liver health. I am not surprised that the observed associations were
attenuated by controlling for insulin sensitivity given the fact that fatty liver and
impaired insulin sensitivity are highly correlated. It is very critical to adjust dietary
factors as the authors did in model 3, but my major concern is sugar
consumption (primarily fructose) should be also controlled as a confounder. Tons
of evidence has proposed fructose (e.g. from sugar-sweetened beverages) as a
culprit of NAFLD. It could be that habitually higher coffee consumers are more
likely to have less sugar-sweetened drinks which could be an underlying link for
the authors’ reported inverse associations in this study. It will be more convincing
to me if the sugar adjustment could be performed, so I will take this as a request
for major compulsory revisions. In addition, a minor concern is although the
reported inverse associations are statistically significant, correlation coefficients
are small numbers (almost > - 0.1 for all) thus how important it will be in the
biological nature?
Level of interest: An article of importance in its field
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:Associations of Coffee Consumption with Markers of Liver Injury in the
Insulin Resistance Atherosclerosis Study
Version:2Date:27 February 2015
Reviewer: Ran Jin
Reviewer's report:
Dickson et al. identified significant inverse associations of caffeinated coffee
consumption with ALT, AST, and the NAFLD liver fat score, suggesting a
beneficial impact of caffeinated coffee consumption on liver-related outcomes.
Generally, this is a well-organized and well-written manuscript of important
interest in the related research field. The authors have clearly stated the current
knowledge gaps and posed their research questions, also the methods are
sufficiently provided to support their findings. I am very pleased to review this
work and following are my comments and suggestions. The authors have
adjusted several clusters of potential confounds in the linear regression models
aiming to analyze an independent relationship between coffee consumption and
the liver health. I am not surprised that the observed associations were
attenuated by controlling for insulin sensitivity given the fact that fatty liver and
impaired insulin sensitivity are highly correlated. It is very critical to adjust dietary
factors as the authors did in model 3, but my major concern is sugar
consumption (primarily fructose) should be also controlled as a confounder. Tons
of evidence has proposed fructose (e.g. from sugar-sweetened beverages) as a
culprit of NAFLD. It could be that habitually higher coffee consumers are more
likely to have less sugar-sweetened drinks which could be an underlying link for
the authors’ reported inverse associations in this study. It will be more convincing
to me if the sugar adjustment could be performed, so I will take this as a request
for major compulsory revisions. In addition, a minor concern is although the
reported inverse associations are statistically significant, correlation coefficients
are small numbers (almost > - 0.1 for all) thus how important it will be in the
biological nature?
Level of interest: An article of importance in its field
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.
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