Barriers and Facilitators of Tobacco Cessation Interventions at the Population and Healthcare System Levels: A Systematic Literature Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

Thank you for allowing me to review your work. The study is particularly important for assessing existing interventional effects on cessation rates, as far as I am aware, there have been almost no studies, including systematic literature reviews, that address the research question at hand. If published, it would undoubtedly serve as a foundation for future relevant studies. The manuscript's structure is clear and well-written. That being said, I have the following minor comments if the authors may consider it:

1. As the authors attempt to create a forest plot or conduct a pooled analysis, in my opinion, it is not required for the following reasons, and I would suggest removing the entire section to be clear for readers, and just keep it as a synthesis systematic review:                  a The present study is a systematic literature review, not a meta-analysis, as the authors mention in the text.                                                                                                                  Heterogeneity is likely to be significant, given the substantial differences in interventions and study characteristics. Although authors perform a random effects model, it is for future research (if authors undertake it) to focus on just one intervention or multiple interventions in different models to identify less heterogeneous, narrower CI effect sizes 
2. The same applies to the funnel plot, as it might mislead readers to assume it is a meta-analysis, where instead authors are performing an important synthesis on a rare topic

Thank you,

Good Luck

 

Author Response

Comment 1.As the authors attempt to create a forest plot or conduct a pooled analysis, in my opinion, it is not required for the following reasons, and I would suggest removing the entire section to be clear for readers, and just keep it as a synthesis systematic review: a The present study is a systematic literature review, not a meta-analysis, as the authors mention in the text.                  Heterogeneity is likely to be significant, given the substantial differences in interventions and study characteristics. Although authors perform a random effects model, it is for future research (if authors undertake it) to focus on just one intervention or multiple interventions in different models to identify less heterogeneous, narrower CI effect sizes :

Thank you for your kind words. We have attempted to address your feedback as follows
and our point by point response is in blue color:

a. Thank you for your insightful feedback. We have now excluded the
sections suggested as we agree with your perspective.

Comment 2. The same applies to the funnel plot, as it might mislead readers to assume it is a
meta-analysis, where instead authors are performing an important synthesis on a
rare topic:
- Thank you for your insightful feedback. We have now excluded the
sections suggested as we agree with your perspective.

Reviewer 2 Report

Comments and Suggestions for Authors

Beautiful study idea! hard to believe only 35 studies met inclusion criteria - which means not much is undertaken to tackle tobacco pandemic systematically and provide effective treatment options. It would be great to see what would change if interventions are rolled out more broadly. On the other hand it is frustrating to see the low effect scores.

What is the main question addressed by the research?

Barriers and facilitators for successful tobacco cessation programs in healthcare system and population based interventions in the US

Do you consider the topic original or relevant to the field? Does it address a specific gap in the field? Please also explain why this is/ is not the case. 

Considering the focus of this issue "ONE Health" there should be some other regions in the world included and also issues around environmental concerns in growing, harvesting, shipping tobacco, waste management, and also working force's rights; the topic is relevant, some (creative) best practice models (e.g. such as Ottawa model of smoking cessation https://www.ottawaheart.ca/patients-visitors/centres-and-programs/omsc/ottawa-model-smoking-cessation) could be presented to improve comprehension.

What does it add to the subject area compared with other published material?

Systematic overview of "lessons learned" in one important/leading area of the world

What specific improvements should the authors consider regarding the methodology?

Maybe some more information on exclusion criteria

Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed? Please also explain why this is/is not the case.

Yes - great statistics

Are the references appropriate?

yes

Author Response

Comment-1: Do you consider the topic original or relevant to the field? Does it address a specific gap
in the field? Please also explain why this is/ is not the case. 
Considering the focus of this issue "ONE Health" there should be some other regions in
the world included and also issues around environmental concerns in growing,
harvesting, shipping tobacco, waste management, and also working force's rights; the
topic is relevant, some (creative) best practice models (e.g. such as Ottawa model of
smoking cessation https://www.ottawaheart.ca/patients-visitors/centres-and-
programs/omsc/ottawa-model-smoking-cessation) could be presented to improve
comprehension.

Response: Thank you for your thoughtful comment.

While we recognize the global relevance of tobacco control and the intersection of tobacco production and environmental, labor, and health justice concerns, we respectfully clarify that the scope of our study is intentionally limited to the U.S. context. This geographic focus is central to the manuscript’s objectives, which are to examine domestic gaps in tobacco control policy
through a justice and equity lens, particularly in the context of the U.S. public health and regulatory environment. As highlighted in the manuscript, our aim is to identify national-level policy gaps and justice implications, rather than to provide a comparative or international analysis.Regarding the inclusion of environmental issues, labor rights, and models like the
Ottawa Model of Smoking Cessation, these are indeed important and worthy of exploration. However, integrating these topics would expand the scope of the paper beyond its intended U.S.-centric justice analysis. We have clarified our rationale for this scope in the revised manuscript.

Comment :2 What does it add to the subject area compared with other published material?

This review provides a comprehensive analysis of both individual and systemic barriers and facilitators to tobacco cessation in the U.S.—a perspective that is often fragmented or underrepresented in existing literature. Unlike prior studies that typically focus on isolated intervention types or specific populations, this review integrates findings across diverse demographic groups and intervention strategies, quantifies pooled effect sizes for both medical and non-medical approaches, and highlights the importance of culturally tailored and digitally enabled solutions.

Comment-3: What specific improvements should the authors consider regarding the methodology?

Thank you for bringing this to our attention. We have now extensively revised the Methods section to incorporate the changes as per the feedback from other reviewers. We hope it meets your expectations.

Comment-4:Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed? Please also explain why this is/is not the case.

Yes, mention the strength or range of effect sizes for key interventions.

Reviewer 3 Report

Comments and Suggestions for Authors

This review article is to identify barriers and facilitators of smoking cessation interventions at the levels of population and healthcare system. The following is my questions and suggestions.

 

Introduction

1. Authors argued that the previous studies identifying the barriers and facilitators have limitations on focusing on specific subpopulations or intervention modalities. And thus, one of the aims in the study is to consider the population and healthcare system level barriers and facilitators. However, if the disparities in tobacco use and intervention utilization are the important reason to identify the barriers and facilitators, is it important to consider the barriers and facilitators at the population level? I don’t think that the previous studies identifying the barriers and facilitators in specific subpopulation would be totally significant. Moreover, I don’t know the meaning of the “population” in this study. The studies included in this review rarely covered the population – Rather, studies focused on certain subpopulations (e.g., low SES group and a certain racial/ethnic group such as African American) and this review simply added or combined these studies. Also, I am not sure that the addition or combinations of all studies can cover a good range of population. For example, a lot of studies included in this review recruited only low SES group, not enough high SES group. All these are also applied to the issue of intervention modalities.

I believe this issue is very important to evaluate the originality and innovation of this review. The barriers and facilitators identified in this review are not very different from ones that authors listed in the introduction (those identified in the problematic previous studies or reviews). More importantly, the addition or combination of the previous studies focusing on a specific subpopulations or intervention modalities must be supported by the test of between-study heterogeneity.

 

2. I am not sure why authors brought the data from low- and middle-income countries at the beginning of the manuscript. This review only focused on the studies in the US.

 

3. What does “ESC-DAG” mean? I believe the full term should have been presented at the first show.

 

4. While I understand the importance/significance of identifying the barriers and facilitators of smoking cessation interventions, I believe the second paragraph is a bit weak to explain this importance/significance. The sentences in the third paragraph (“any treatment before implementation … work in public health.”) could be incorporated in the second paragraph and strengthen the importance/significance of reviews.

 

Materials and methods

5.” The search terms … appendix Table 1A.” -> Table A.1.?

 

6. I believe another important issue of this review is the criterion to identify barriers and facilitators. At least, authors should have explained how they identified the barriers and facilitators. As I checked the studies included in this review, the studies did not directly examine the barriers and facilitators of the smoking interventions, but they suggested the barriers and facilitators as a way to explain their significant or non-significant effects of the smoking cessation interventions.

 

Results

7. Studies suggested the financial incentives as a key barrier (i.e., Baggett et al., 2018; Kendzor et al., 2024) did show the significant group differences in the treatment effects at the short-term follow-ups but not at the long-term follow-ups. In these cases, is it still fine to say the financial incentives as a key barrier? Also, related studies suggesting the SES or finance related factors as a barrier only included the low SES populations (e.g., homeless, SES disadvantaged mothers). Is it still find to suggest the barriers and facilitators at the population level?

 

8. While interventions targeting language barriers showed varied effectiveness, how authors decided the incorporation of multilingual components as a facilitator? Especially, Chen et al. (2021)’s study showed the multilingual components reduced cessation rates (it’s another story that this study compared the treatment and control group that got the different types of treatment at different years – 2004-2008 vs 2012-2019).

 

9. I wonder how authors identified the barriers and facilitators from the studies that did not show any significant effects of smoking cessation intervention and how these studies were incorporated in this review (authors rarely mentioned any barriers or facilitators from these studies). Special concern is Heffner et al. (2020)’ study. When the study did not find the group differences in intervention effects between sexual minority and nonminority, how authors identified the minority stress and stigma as a barrier (especially, minority stress and stigma were not assessed in the study).

 

10. I am not sure that Medicaid expansion can be regarded as smoking cessation intervention in Bailey et al. (2020)’s study – I did not find any specific clinical trial in this study. Also, there were a lot of baseline differences between smokers of Medicaid expanded states vs. those of Medicaid not expanded states, which could be the reasons of the smoking cessation outcomes. How did authors confirm that the difference in smoking cessation between groups attributed to the Medicaid expansion?

 

Discussion

11. A lot of barriers and facilitators were identified in the results even though the criterion is not clear. Then, how did authors select some of them as common barriers and facilitators in the first paragraph in discussion?

 

12. In the third paragraph, authors suggested that future studies need to utilize stratified analyses to identify the barriers and facilitators for specific subpopulations considering the high heterogeneity in studies. I believe it is the limitations in the previous reviews motivating the current review. What is the contribution of this review to the research field? What do you think the originality and innovation of this review?

Author Response

Comment -1:

1. Authors argued that the previous studies identifying the barriers and facilitators have limitations on focusing on specific subpopulations or intervention modalities. And thus, one of the aims in the study is to consider the population and healthcare system level barriers and facilitators. However, if the disparities in tobacco use and intervention utilization are the important reason to identify the barriers and facilitators, is it important to consider the barriers and facilitators at the population level? I don’t think that the previous studies identifying the barriers and facilitators in specific subpopulation would be totally significant. Moreover, I don’t know the meaning of the “population” in this study. The studies included in this review rarely covered the population – Rather, studies focused on certain subpopulations (e.g., low SES group and a certain racial/ethnic group such as African American) and this review simply added or combined these studies. Also, I am not sure that the addition or combinations of all studies can cover a good range of population. For example, a lot of studies included in this review recruited only low SES group, not enough high SES group. All these are also applied to the issue of intervention modalities.

I believe this issue is very important to evaluate the originality and innovation of this review. The barriers and facilitators identified in this review are not very different from ones that authors listed in the introduction (those identified in the problematic previous studies or reviews). More importantly, the addition or combination of the previous studies focusing on a specific subpopulations or intervention modalities must be supported by the test of between-study heterogeneity.

Response:

We greatly appreciate this thoughtful and detailed comment. We agree that clarifying the conceptual framework, terminology, and methodological rationale is important for evaluating the contribution and innovation of this review.

1.  We acknowledge the reviewer’s concern regarding the term "population level." In our revised manuscript, we have clarified this term to mean barriers and facilitators experienced by individuals or groups receiving tobacco cessation
   interventions, as opposed to those at the healthcare system level, which relate to implementation infrastructure (e.g., provider training, insurance coverage, service delivery mechanisms). Thus, the "population level" in our study refers to sub
   groups, often stratified by socioeconomic status, race/ethnicity, gender,geography, or mental health status. We have updated the manuscript to explicitly state this definition in the Introduction.
2. Regarding the scope of included studies, we agree that many studies focus on underserved or high-risk subpopulations. This reflects both the intent of interventions to reduce disparities and the practical challenges of generalizing findings to more affluent populations. While we did not find substantial data from high SES populations (a noted limitation), our aim was not to achieve representative coverage of the entire U.S. population but rather to synthesize cross-cutting determinants of success or failure across diverse contexts and interventions that are often underrepresented in reviews.
3. We acknowledge that barriers and facilitators observed in these focused studies may not generalize to all population segments. However, our contribution lies in systematically identifying recurrent themes across studies that, while focused on different subpopulations, highlight common individual-level and structural challenges.
4. On the point regarding originality, we respectfully note that although prior studies have identified individual barriers and facilitators, they typically do so within a limited scope (e.g., only pregnant smokers, or only behavioral interventions). Our review contributes by integrating evidence from both medical and non-medical interventions, at both the population and system levels, and linking those findings with cessation outcomes where possible. This multilevel synthesis is absent in previous reviews. We have revised the Introduction to better distinguish our review from earlier work and more clearly state the gap we address.
5. Lastly, regarding heterogeneity, we acknowledge the reviewer’s point about combining diverse studies. To address this, we employed a random-effects model to estimate pooled effect sizes, as detailed in the Methods (section 2.4) of the submitted version of the manuscript. We had to remove the section to improve coherence and readability at the request of another reviewer.  We have now added highlighted relevant text in lines 108-123, 174-192, and 385-392.

Comment 2:

I am not sure why authors brought the data from low- and middle-income countries at the beginning of the manuscript. This review only focused on the studies in the US.

Response: Thank you for this observation. We agree that the primary focus of our review is on studies conducted within the United States. The mention of tobacco use in low- and middle-income countries (LMICs) in the Introduction was intended to provide global context for the public health burden of tobacco use. However, we recognize that this may be perceived
as misaligned with the study’s U.S.-specific scope.
                   - In response, we have revised the Introduction to limit the focus to the burden and context of tobacco use in the U.S., Lines 37-39.

Comment:3

What does “ESC-DAG” mean? I believe the full term should have been presented at the first show.

Response:

Thank you for pointing this out. We agree that acronyms should be fully spelled out upon first use to ensure clarity for all readers. In response, we have revised the manuscript to introduce “ESC-DAG” as “Evidence Synthesis for Constructing Directed Acyclic Graphs (ESC-DAG)” at its first mention in the Introduction, hence we have added relevant words in
lines 86-87 added.

Comment-4:

While I understand the importance/significance of identifying the barriers and facilitators of smoking cessation interventions, I believe the second paragraph is a bit weak to explain this importance/significance. The sentences in the third paragraph (“any treatment before implementation … work in public health.”) could be incorporated in the second paragraph and strengthen the importance/significance of reviews.

Response: We appreciate the reviewer’s suggestion to strengthen the rationale and significance of the review. In response, we have revised the second paragraph of the Introduction to incorporate key content from the third paragraph, specifically
the explanation that interventions tested under ideal, controlled settings may yield different outcomes in real-world environments due to contextual and structural barriers and facilitators. We have now added lines 58-64.

Comment-5:

Materials and methods

5.” The search terms … appendix Table 1A.” -> Table A.1.?

Response:

Thank you for your attention to detail. We have now corrected it to accurately reflect the in-text reference.

Comment 6: I believe another important issue of this review is the criterion to identify barriers and facilitators. At least, authors should have explained how they identified the barriers and facilitators. As I checked the studies included in this review, the studies did not directly examine the barriers and facilitators of the smoking interventions, but they suggested the barriers and facilitators as a way to explain their significant or non-significant effects of the smoking cessation interventions.

Response: We thank the reviewer for this valuable comment. We acknowledge that most of the included studies did not examine barriers and facilitators as their primary focus. As such, we adopted a qualitative content analysis approach to identify and extract relevant barriers and facilitators that were discussed in the included studies as part of their interpretation of findings whether in the discussion, limitations, or conclusion sections. In response to the reviewer’s comment, we have revised the manuscript to clarify our process of identifying barriers and facilitators. Specifically, we now state in lines 153 – 159.

Comment-7:Results

Studies suggested the financial incentives as a key barrier (i.e., Baggett et al., 2018; Kendzor et al., 2024) did show the significant group differences in the treatment effects at the short-term follow-ups but not at the long-term follow-ups. In these cases, is it still fine to say the financial incentives as a key barrier? Also, related studies suggesting the SES or finance related factors as a barrier only included the low SES populations (e.g., homeless, SES disadvantaged mothers). Is it still find to suggest the barriers and facilitators at the population level?

Response: We thank the reviewer for this nuanced and important comment. We agree that it is essential to distinguish between short-term effectiveness and long-term sustainability of interventions, especially when assessing the role of financial
incentives. In the studies cited (e.g., Baggett et al., 2018; Kendzor et al., 2024), the observed effects of financial incentives were indeed more pronounced at short-term follow-ups.
1 We have revised the manuscript to clarify that financial incentives may serve as short-term facilitators that enhance initial cessation rates, particularly in highly disadvantaged populations, but may have limited sustained impact without ongoing support or reinforcement strategies in lines 385-392.
2 Regarding the second point, we acknowledge that most of the studies citing SES-related barriers or facilitators were conducted within low- income or vulnerable groups. As such, our use of the term “population level” does not imply generalizability to the entire population, but rather refers to the end-user or recipient perspective as opposed to healthcare system-level implementation factors. We have clarified this usage in both the Introduction and Methods sections and now explicitly note in the Discussion that our findings are most applicable to the underserved populations disproportionately affected by tobacco use and cessation disparities.
3 We have also included a statement in the Limitations section acknowledging the limited representation of higher SES groups in the included studies, and that caution should be exercised when extrapolating these findings to broader populations.

 

Comment 8: While interventions targeting language barriers showed varied effectiveness, how authors decided the incorporation of multilingual components as a facilitator? Especially, Chen et al. (2021)’s study showed the multilingual components reduced cessation rates (it’s another story that this study compared the treatment and control group that got the different types of treatment at different years – 2004-2008 vs 2012-2019).

Response: We appreciate the reviewer’s observation and the reference to the nuanced findings of Chen et al. (2021). In our review, the inclusion of multilingual components as a facilitator was guided by how the original studies framed language accessibility in their intervention design and implementation. Specifically, we considered a component to be
a facilitator if it was explicitly intended to improve engagement, acceptability, or effectiveness among racial and ethnic minoritized groups by addressing language needs regardless of the ultimate measured impact on cessation rates.
For example, several studies (e.g., Zhu et al., 2010; Webb Hooper et al., 2020; Graham et al., 2016) implemented multilingual or language-adapted interventions with the aim of increasing cultural and linguistic relevance for Spanish-speaking participants. These components were classified as facilitators in our synthesis because they were
introduced to overcome a known barrier—language mismatch—and were often accompanied by culturally congruent materials or staff, reflecting a deliberate effort to support access and engagement.We acknowledge that Chen et al. (2021) found lower cessation rates among multilingual services compared to English-language services. However, as noted by the reviewer, that study compared two cohorts from different time periods and with structurally different treatment protocols. Thus, the multilingual component may have been confounded by other factors such as changes in service delivery or participant demographics over time. Importantly, Chen et al. themselves suggested that the intent of the multilingual services was to improve reach and inclusivity among diverse populations—a rationale aligned with our classification criteria.
To clarify this in the manuscript, we have inculcated the revisions in lines 393-403.

 

Comment 9: I wonder how authors identified the barriers and facilitators from the studies that did not show any significant effects of smoking cessation intervention and how these studies were incorporated in this review (authors rarely mentioned any barriers or facilitators from these studies). Special concern is Heffner et al. (2020)’ study. When the study did not find the group differences in intervention effects between sexual minority and nonminority, how authors identified the minority stress and stigma as a barrier (especially, minority stress and stigma were not assessed in the study).

Response:

We thank the reviewer for raising this important point regarding the inclusion of studies without statistically significant intervention effects and the identification of barriers and facilitators from such studies. Our approach in this scoping review was to include studies that implemented cessation interventions with racially/ethnically minoritized and/or sexual and gender minority (SGM) populations, regardless of whether they found statistically significant differences in cessation outcomes. This decision was intentional and consistent with scoping review methodology, which prioritizes mapping the scope and nature of available evidence rather than restricting inclusion to studies with positive findings. These studies are critical for understanding the broader implementation landscape, including contextual and process-related barriers and facilitators.
In the case of studies that did not report significant group differences, such as Heffner et al. (2020)—barriers and facilitators were extracted based not only on outcome data but also from the authors’ descriptions, interpretations, and discussion of
implementation issues or contextual challenges. In Heffner et al. (2020), although minority stress and stigma were not quantitatively assessed as variables, the authors discussed these constructs as relevant contextual factors potentially influencing engagement and outcomes for sexual minority participants. Specifically, they referenced minority stress theory and prior evidence suggesting SGM-specific stressors may impact cessation. In our synthesis, we noted this discussion as indicative of how stigma and minority stress are perceived to interact with cessation efforts, even if not directly
measured in the study. To address this concern, we have now clarified in lines 174-192.

Comment:10: I am not sure that Medicaid expansion can be regarded as smoking cessation intervention in Bailey et al. (2020)’s study – I did not find any specific clinical trial in this study. Also, there were a lot of baseline differences between smokers of Medicaid expanded states vs. those of Medicaid not expanded states, which could be the reasons of the smoking cessation outcomes. How did authors confirm that the difference in smoking cessation between groups attributed to the Medicaid expansion?

Response:

We appreciate the reviewer’s observation regarding the classification of Medicaid expansion in Bailey et al. (2020) and the complexities of attributing cessation outcomes to policy changes in observational designs. We agree that Medicaid expansion does not constitute a direct smoking cessation intervention in the clinical trial sense. However, in our review, we intentionally adopted a broad definition of “intervention” to include policy-level changes that were explicitly studied for their impact on smoking cessation among racial/ethnic minoritized populations. Bailey et al. (2020) conducted a natural experiment using nationally representative, longitudinal data from the Current Population Survey to examine smoking cessation before and after Medicaid expansion, comparing expansion and non-expansion states.The study explicitly aimed to assess the effect of Medicaid expansion on smoking cessation and reported stratified results by race/ethnicity, showing a greater increase in
cessation among Hispanic individuals in expansion states. While we acknowledge that causal inference is limited by potential baseline differences and the absence of randomization, the study design (difference-in-differences approach) and temporal
framing align with public health evaluations of structural interventions. In our synthesis, we included Bailey et al. (2020) as an example of a policy-level intervention with population-level reach and stratified evaluation by race/ethnicity. We have now clarified in the manuscript that this study reflects a natural experiment rather than a clinical trial and that observed effects may be influenced by unmeasured confounding. We have also clarified that in lines 413-441

Comment:11:

Discussion

A lot of barriers and facilitators were identified in the results even though the criterion is not clear. Then, how did authors select some of them as common barriers and facilitators in the first paragraph in the discussion?

Response: We appreciate the reviewer’s request for greater clarity on how common barriers and facilitators were identified and highlighted in the Discussion. In our scoping review, we did not apply quantitative thresholds (e.g.,
frequency counts) to formally rank barriers and facilitators. Instead, we used a qualitative content analysis approach to identify patterns across studies, considering both the frequency with which a barrier or facilitator was reported and the salience given by study authors in their interpretations.
The barriers and facilitators referenced in the first paragraph of the Discussion such as access, cost, culturally appropriate tailoring, and trust were those most consistently emphasized across multiple studies and intervention types. They were also often discussed in relation to broader structural and social determinants, making them especially relevant for public health and implementation science audiences. To address this comment, we have clarified in the lines 174-192.

Comment : 12: In the third paragraph, authors suggested that future studies need to utilize stratified analyses to identify the barriers and facilitators for specific subpopulations considering the high heterogeneity in studies. I believe it is the limitations in the previous reviews motivating the current review. What is the contribution of this review to the research field? What do you think the originality and innovation of this review?

Response:

We thank the reviewer for this important comment. Indeed, a key motivation for conducting this review was to address gaps left by prior reviews that often grouped racial/ethnic and SGM populations together or
focused exclusively on intervention effectiveness without attending to implementation factors. Our review is, to our knowledge, the first to synthesize evidence specifically on implementation barriers and facilitators of smoking cessation interventions targeting both racially/ethnically minoritized and SGM populations in the U.S., with an emphasis on equity-
relevant implementation factors (e.g., language access, cultural tailoring, stigma, structural barriers).
This review makes two key contributions. First, it extends the literature by systematically mapping implementation experiences rather than solely focusing on cessation outcomes. Second, it highlights under-reported and population-specific contextual factors (e.g., minority stress, immigration- related access barriers) that influence intervention uptake and success.
We have now added lines 432-441 to include the clarification.

Reviewer 4 Report

Comments and Suggestions for Authors

• Page 3 of 24, Section 2.3 (Screening Questions)
  It would be better if the authors could provide more details regarding the inclusion and exclusion criteria, such as the study period.

• Table 1A and Table 2A
  It would be helpful if the authors could also include the study period for each study.

• Multiple Figures Labeled as “Figure 1” (Random Effects Forest Plot)
  Several studies display odds ratios with 95% confidence intervals that were below 0. The authors may need to explain or clarify how these values were obtained.

• Table and Figure Labeling
  Please ensure all tables and figures are labeled correctly. Avoid duplicated or incorrect labels.

Author Response

Comment-1:Page 3 of 24, Section 2.3 (Screening Questions)
It would be better if the authors could provide more details regarding the inclusion and exclusion criteria, such as the study period.

Response: Thank you for your attention to detail. We have now added a line in
section 2.2. regarding the same (i.e., lines 140-141).

Comment-2: Table 1A and Table 2A
It would be helpful if the authors could also include the study period for each study.

Response: Thank you for this suggestion. We considered including the study period for each study. However, we chose to limit the number of variables presented in the results tables to maintain clarity and readability, as the tables are already large and contain extensive data. Given that this is not a meta-analysis and we are not assessing temporal trends or time-based
variations in outcomes, we did not consider the study period to be a critical variable for inclusion in the summary tables. Our focus was on the most policy-relevant and outcome-focused variables, as discussed in the revised manuscript. We hope the reviewer understands our rationale for this decision.

Comment:3 Multiple Figures Labeled as “Figure 1” (Random Effects Forest Plot)
Several studies display odds ratios with 95% confidence intervals that were below 0. The authors may need to explain or clarify how these values were obtained.

Response:Thank you for bringing this to our attention. We have now removed the forest plots and funnel plots from the study, upon request by another reviewer to improve readability and coherence.

Comment:3 Table and Figure Labeling
Please ensure all tables and figures are labeled correctly. Avoid duplicated or incorrect labels.

Response: Thank you for bringing this to our attention. We have now ensured that the
table and figure captions are accurate.

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

I believe all my suggestions and questions are well considered and addressed. I do not have any more suggestions or questions. I am still a little worried that many of barriers and facilitators that original studies suggested are included without reinterpretation or reconsideration, but authors' clarifications in the revised manuscript compensated this issue a lot.

Reviewer 4 Report

Comments and Suggestions for Authors

All comments have been appropriately addressed.