Title: Association between Dietary Inflammatory Index and Ulcerative Colitis: A Case-control
Study
Version: 1 Date: 21 Jan 2025
Reviewer's report:
Authors aims to confirm the causal relationship between DII and the onset of UC, as well as
the impact of DII on disease activity in UC patients, using a cross-sectional survey. The topic is
intriguing indeed, but there are some comments that need to be addressed or answered.
1.
The authors have conducted a cross-sectional survey of the dietary habits of individuals who
have already developed UC. To confirm whether DII is a cause of UC onset, data on DII before
the onset of UC is necessary, as the dietary habits could have changed after the onset of UC or
been modified in response to disease symptoms. Additionally, dietary habits change over time.
For these reasons, it seems difficult to assess a causal relationship regarding the onset mechanism
of UC based on a cross-sectional survey of individuals who have already developed UC.
2.
The aforementioned issue also applies when examining the relationship between DII and disease
activity. For those who are already experiencing exacerbation, their diet is likely to have changed
after a flare-up in terms of both content and intake. It would be more appropriate to longitudinally
assess whether differences in DII among individuals with similar background factors impact
future differences in disease activity. Furthermore, disease activity is likely to be strongly
influenced by other factors, such as current treatments and/or disease type.
3.
The authors state, “The correlation analysis between DII and UC was performed after adjusting
for confounders, which had a strong reliability.” However, in the text, only total energy intake
and use of medication are mentioned as covariate factors. Please specify all the confounding
factors that were adjusted for. Additionally, with only 106 cases (remission 50 / active 56), due
to the issue of overfitting, it seems that there may be limitations on the number of variables that
can be included in the regression model.
4.
Please consider factors such as age, sex, disease type, disease duration, UC treatment
medications, socioeconomic status as confounding factors between diet and UC disease activity.
5.
The authors state, “An Iranian study showed that UC was associated with increased DII (12).
Lamers demonstrated that the relationship between DII and disease activity is not significant in
UC,” and in this study, authors are also evaluating the same aspects as prior studies, namelly DII
and UC risk, as well as UC disease activity. Please clarify what the knowledge gap is between
DII and UC, and clearly state what the novelty of this study is.
6.
Please describe how the control group was selected. Was it matched based on any factors?
7.
Please add the information about comorbidities, and medications to Table 1. Similarly, for Table
2, please include important factors for confirming the causal relationship between DII and UC
disease activity such as disease type, disease duration.
Title: Association between Dietary Inflammatory Index and Ulcerative Colitis: A Case-control
Study
Version: 1 Date: 21 Jan 2025
Reviewer's report:
Authors aims to confirm the causal relationship between DII and the onset of UC, as well as
the impact of DII on disease activity in UC patients, using a cross-sectional survey. The topic is
intriguing indeed, but there are some comments that need to be addressed or answered.
1.
The authors have conducted a cross-sectional survey of the dietary habits of individuals who
have already developed UC. To confirm whether DII is a cause of UC onset, data on DII before
the onset of UC is necessary, as the dietary habits could have changed after the onset of UC or
been modified in response to disease symptoms. Additionally, dietary habits change over time.
For these reasons, it seems difficult to assess a causal relationship regarding the onset mechanism
of UC based on a cross-sectional survey of individuals who have already developed UC.
2.
The aforementioned issue also applies when examining the relationship between DII and disease
activity. For those who are already experiencing exacerbation, their diet is likely to have changed
after a flare-up in terms of both content and intake. It would be more appropriate to longitudinally
assess whether differences in DII among individuals with similar background factors impact
future differences in disease activity. Furthermore, disease activity is likely to be strongly
influenced by other factors, such as current treatments and/or disease type.
3.
The authors state, “The correlation analysis between DII and UC was performed after adjusting
for confounders, which had a strong reliability.” However, in the text, only total energy intake
and use of medication are mentioned as covariate factors. Please specify all the confounding
factors that were adjusted for. Additionally, with only 106 cases (remission 50 / active 56), due
to the issue of overfitting, it seems that there may be limitations on the number of variables that
can be included in the regression model.
4.
Please consider factors such as age, sex, disease type, disease duration, UC treatment
medications, socioeconomic status as confounding factors between diet and UC disease activity.
5.
The authors state, “An Iranian study showed that UC was associated with increased DII (12).
Lamers demonstrated that the relationship between DII and disease activity is not significant in
UC,” and in this study, authors are also evaluating the same aspects as prior studies, namelly DII
and UC risk, as well as UC disease activity. Please clarify what the knowledge gap is between
DII and UC, and clearly state what the novelty of this study is.
6.
Please describe how the control group was selected. Was it matched based on any factors?
7.
Please add the information about comorbidities, and medications to Table 1. Similarly, for Table
2, please include important factors for confirming the causal relationship between DII and UC
disease activity such as disease type, disease duration.
Please review this paper.
user
Title: Association between Dietary Inflammatory Index and Ulcerative Colitis: A Case-control
Study
Version: 1 Date: 21 Jan 2025
Reviewer's report:
Authors aims to confirm the causal relationship between DII and the onset of UC, as well as
the impact of DII on disease activity in UC patients, using a cross-sectional survey. The topic is
intriguing indeed, but there are some comments that need to be addressed or answered.
1.
The authors have conducted a cross-sectional survey of the dietary habits of individuals who
have already developed UC. To confirm whether DII is a cause of UC onset, data on DII before
the onset of UC is necessary, as the dietary habits could have changed after the onset of UC or
been modified in response to disease symptoms. Additionally, dietary habits change over time.
For these reasons, it seems difficult to assess a causal relationship regarding the onset mechanism
of UC based on a cross-sectional survey of individuals who have already developed UC.
2.
The aforementioned issue also applies when examining the relationship between DII and disease
activity. For those who are already experiencing exacerbation, their diet is likely to have changed
after a flare-up in terms of both content and intake. It would be more appropriate to longitudinally
assess whether differences in DII among individuals with similar background factors impact
future differences in disease activity. Furthermore, disease activity is likely to be strongly
influenced by other factors, such as current treatments and/or disease type.
3.
The authors state, “The correlation analysis between DII and UC was performed after adjusting
for confounders, which had a strong reliability.” However, in the text, only total energy intake
and use of medication are mentioned as covariate factors. Please specify all the confounding
factors that were adjusted for. Additionally, with only 106 cases (remission 50 / active 56), due
to the issue of overfitting, it seems that there may be limitations on the number of variables that
can be included in the regression model.
4.
Please consider factors such as age, sex, disease type, disease duration, UC treatment
medications, socioeconomic status as confounding factors between diet and UC disease activity.
5.
The authors state, “An Iranian study showed that UC was associated with increased DII (12).
Lamers demonstrated that the relationship between DII and disease activity is not significant in
UC,” and in this study, authors are also evaluating the same aspects as prior studies, namelly DII
and UC risk, as well as UC disease activity. Please clarify what the knowledge gap is between
DII and UC, and clearly state what the novelty of this study is.
6.
Please describe how the control group was selected. Was it matched based on any factors?
7.
Please add the information about comorbidities, and medications to Table 1. Similarly, for Table
2, please include important factors for confirming the causal relationship between DII and UC
disease activity such as disease type, disease duration.
assistant