Prevalence of Multiple Chemical Sensitivity in Canada Between 2000 and 2020
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsI found the manuscript interesting. I've made several suggestions in the attached file. I understand that this is intended to be a brief report; however, some additional detail would be helpful. Specifically, you start the manuscript with three highlights related to public health. These are not addressed in your discussion.
I found the discussion criteria of interest and would like to know more about why the subgroups were excluded.
I would like to know more about the survey you used to gather your data. For example, what is the survey cycle? How is the survey conducted? Is it in person, telephone or other means? Has the survey been validated? If interviewers are involved, what is the mechanism to prevent interviewer bias?
As this is an international journal, some description of the provinces might be appropriate-what is the difference between the maritime provinces and others?
See comments in the attached file.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript addresses an important topic, but several aspects require clarification and improvement.
- Introduction
The introduction summarizes many studies from Japan, Denmark, Spain, the USA, Australia, and Canada, including Ontario 2005 and CCHS 2012, but it does not state what is still unknown. It does not explain why an analysis covering 2000 to 2020 is needed compared with what already exists. The final sentence only announces the topic, not a new contribution.
- Materials and Methods
The section describes the CCHS data source and the survey question used to identify MCS, but it provides little methodological detail. The exclusion of several population groups is listed, yet the implications for representativeness are not addressed.
The change from interviewer-based to online data collection is mentioned, but no method is described to account for its effect on MCS reporting. The analysis is limited to descriptive statistics, with no information on survey weighting, sampling design, or how uncertainty was handled.
The section states what data were used, but not how key sources of bias and variability were managed.
- Results
The section relies almost entirely on tables and figures, while the text mainly repeats the numerical values shown in them. The Results would be clearer if the text focused on a smaller number of key findings instead of restating percentages already visible in Table 1, Table 2, and Figures 1 to 3.
Confidence intervals are presented, but they are not used in the narrative to indicate the precision of the estimates or the uncertainty around differences between provinces, sexes, and age groups. The authors should clarify in the text how these intervals should be interpreted.
The section also mixes overall trends, provincial comparisons, and age and sex patterns without a clear structure. Separating these results more clearly would improve readability and help the reader follow the main findings.
Check the correctness of the data in Figure 1 (Female's MCS > MCS Canada?)
- Discussion
The section starts by restating the main prevalence trend and several province-level values that already appear in the Results. This repetition could be reduced so that the Discussion focuses on interpretation.
The paragraph on regional variation introduces an explanation about the lack of awareness among patients and healthcare providers, but the study does not measure awareness, training, or diagnostic practice. This point should be framed as a hypothesis, not as an explanation.
The sex and age paragraphs include several mechanisms that are not supported by the CCHS data. Examples include assumptions about males being more vocal and about gender bias in how complaints are perceived. These explanations are not supported by the data presented.
International comparisons are used to show similar patterns, but the section does not state what this study adds beyond confirming trends using CCHS data. The authors should state the specific contribution of this analysis within the Canadian context.
- Conclusions and Limitations
Statements about healthcare burden, workplace disability, and accommodation needs are not derived from the CCHS prevalence data analyzed in this study.
Several recommendations, such as changes to medical education, product labeling, greenwashing regulation, and legal recognition, are proposed without being linked to any variables measured in the analysis.
It is recommended to add future research directions linked to the limitations, not only general statements.
Comments on the Quality of English LanguageThe quality of the English language can be assessed more accurately by a language editor or a native English speaker
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors have adequately addressed the comments.
Comments on the Quality of English LanguageThe quality of the English language can be assessed more accurately by a language editor or a native English speaker
