Spirometric Profile among Detergents Factory Workers in the North West Bank of Palestine: A Cross-Sectional Study

Reviewer 1 comments:

Authors’ Response:

This study seems interesting, but it is a bit unclear what it tells and what the focus really is. The text has potentials but more information is needed to be able to evaluate it properly. I have some comments to explain what the challenge is for this manuscript:

Thank you. We updated the entire manuscript, rearranging and adding extra information.

-The title indicates a study among detergent factory workers. However, no factories are described as the population for the study in methods. In the discussion 4.1, it is mentioned that ‘not all factories accept to participate.’. There is no text in methods about this. The methods must be prolonged and include properly how the people in the study were recruited.

We revised the whole methods section and elaborated more in details on the study population and how we selected the study groups and the comparison group

-The introduction is confusing, as it has information about many chemicals, about cleaning work and about production of chemicals. The aim at the end focuses on workers of chemical substances factories. Later, it is not clear what the study was about; are the workers from detergent factories? Or from other chemical production sites? It is important to be precise in the aim and make all information in the introduction relevant for the study. Production is not the same as using detergents for cleaning.

We agree with your comments. We extensively updated and rewrote the introduction taking into account your notes. We hope it is more precise and specific now.

-In methods, the selection of participants is very unclear, and as written above, we need more knowledge about the workers. It is also unclear how the non-workers were selected. It is very important to know these facts, to be able to understand if the results are valid or not. More information in the methods is needed on all these issues.

Also, if factory workers are included, knowledge about this factory is needed so we can understand what the workers are exposed to.

Your comments are valid, and we agree with them. The methodology section now includes more information about the factories, workers, and comparison group.

-Results end up with 94 participants. A test for sample size is mentioned in Methods 2.1, but what were the results? And how are these results calculated in relation to the number you ended up with?

We appreciate your noting this. We modified this section by adding a paragraph detailing the sample size calculation, the underlying assumptions, and the resulting sample size.

We changed the section on eligibility criteria to the preceding paragraph; under the Study design and population section.

The spirometry has been performed nicely, and the results show that the lung function of the non-workers is better than among workers. However, this may have several explanations and it is not possible to discuss without more knowledge from methods about the selection of participants. It might be so simple that if workers of a factory are invited to come for an examination, the ones with health problems will volunteer and not the others. We have no possibility to evaluate this and to understand what the findings are related to.

We agree with your comments. We completely updated and rewrote the methodology section in light of your comments, particularly those regarding the selection of study participants; both the detergent factory workers and the comparison group.

It is mentioned that you have asked for time at work and daily exposure? What does that mean, and I cannot see any results from these questions.

We modified the methods sections to describe the measurement tools and the type of information that we obtained in greater detail.

-A detail; lung age must be defined.

Thank you for bringing this to our attention. In both the introduction and the methods section, we added detailed information on lung age with the proper citation.

-The conclusion must be re-written and answer the aim (which needs to be revised). This study cannot lead to a conclusion on use of masks in a factory – no such issues have been mentioned in the text before.

We revised and rephrased the conclusion and recommendations in light with the study results.

-In general, the text will benefit from English language editing. Some unclear parts are probably unclear due to language issues.

We revised the entire manuscript for English, and we hope it is now clearer.

Reviewer 2 comments

Authors’ Response:

Point 1: Extensive editing in English is required. The English language needs proofreading and reworking as I have noticed a number of routine language expressions which are not transferable to English

We made a concentrated effort to improve the clarity of the English throughout the document after going through multiple rounds of editing.

Point 2: The spirometry results may different, but they stay between normal limits, so this difference is not clinically important and may be due to other factors

Yes, we agree with your comment. We brought this up in the discussion and stressed that, while the findings were statistically significant, they were still within the normal clinical range. Nonetheless, we emphasized that the results should be concerning because lung function declines over time.

Point 3: You should compare only % of spirometry parameters and not absolute values, because of the vast variability between normal values depending on the patients special characteristics (age, gender, race, weight and height). The absolute values are used only to estimate differences over time at the same person.

We added a figure in the results section (figure 1) presenting and comparing only the percentages of spirometry parameters

Point 4: Line 104-113: A detailed presentation of the spirometry maneuver is not necessary as long as is performed according to the ERS Standards, as it is already stated

Thank you. We summarized this section in response to your comment.

Point 5: Line 117: chrematistics? you mean characteristics? Also, age and gender are not personal information, they are demographic characteristics

Thank you for noting this. We corrected and rephrased this section.

Point 6: Line 66: Missing an E at FEV1/FVC

Done

Reviewer 3 comments

Authors’ Response:

Generic

Language: Extensive English editing is needed. Single sentence does not constitute a paragraph. Merge either with preceding or following para.

We revised the whole manuscript and rephrased most of its paragraphs and edited for English language. We hope this problem is solved now.

References: Properly cite in-text references. e.g. instead of 1,2,3,4,5, write 1-5.

We reviewed all of the references and standardized the formatting with the assistance of a reference manager.

Please avoid using …etc.. Give full information/idea with a full stop at the end.

We agree with your comment. We revised the whole manuscript and rephrased most of its paragraphs and sentences.

Please be specific and consistent while using “chemical factories workers” or “cleaning chemical factories’ workers”. Better use cleaning/detergent factories’ workers as “Chemical” is very broad term.

Thank you for bringing this to our attention. We revised the entire manuscript and corrected any inconsistencies. We used “detergent factories’ workers” to describe our participants.

Title: Spirometric profile among of detergents factory workers in Palestine: A Cross-Sectional Study. Please also mention the at least the state where study was conducted as a sample of 94 is not representative of “Palestine”

We appreciate your comment and agree with it. We added the location where the study was done to the title.

Abstract:

Lines 18-19: “spirometry was performed to assess workers’ lung functions…” was spirometry done on workers only?

Line 26: “relatively limited working years”….working years were not analyzed. Please write conclusion in line with study methods and results.

Authors may consider adding “occupational health” as a key word

We revised the whole abstract and updated it in line with your comments. We added the “occupational health” as a key word.

Introduction

Please organize the introduction part. There is duplication and redundancy. First explain the chemical and detergents (types, uses, production) briefly then talk about exposures and health outcomes. Then authors may talk about spirometry. Finally give the rational that why was the current study conducted and what would be the importance of the study findings.

Thank you for your advice on how to structure the introduction. We extensively updated and rewrote the introduction based on your suggestions. We believe it is acceptable now and simple to read.

Lines 63-65: “Compared…..FEV1/FVC.” In these lines, authors seem to present findings of current study. Please avoid any such presentation in the introduction

We agree with your viewpoint. We removed this part entirely from the introduction. We reinserted it in the discussion with appropriate English editing and rephrasing.

Line 73: Please specify which workers were included in the German study? Were these detergent factory workers or some other occupation?

As previously stated, we revised the entire introduction. We felt it was more acceptable to remove the German study because it was so old (published in 1987), and we replaced it with more recent literature.

Methods

Methods in general need more details and clarity specially in in terms of sample and sampling.

Authors mentioned “a random population sample of men…”

· Where from the participants selected?

· How did the researchers approach the participants.

· How large is the population (detergent workers)

· Where from non-workers selected?

· Who were non-worker. Were they unemployed or working in some other occupation? If so, their occupational history in important.

We revised the whole methods section and elaborated more in details on the study population and how we selected the study groups and the comparison group and all other points mentioned in your comment.

Line 94: The heading given is “Sample size”, however, under the heading, authors have mentioned exclusion criteria. Please describe the assumptions and calculated sample size.

Spirometry: Please specify if you considered “smoking shortly before spirometry”? Also mention about the quality grades of spirometry results. Were the spirometric results of some of the participants rejected because of quality issue? If yes, please specify. Please also mention the reference value used for predicted values.

Thank you for noting this. We modified this section by adding a paragraph detailing the sample size calculation, the underlying assumptions, and the resulting sample size.

We changed the section on eligibility criteria to the preceding paragraph; under the Study design and population section.

Results:

Please provide the meaning of “*” and other symbols used in tables as footnotes. In the methods, author mentioned that data was collected on “participants' occupation status (working in chemical detergent factories, time in working in these factories, and daily exposure to detergents.)”. However, there is no such analyses or results related to these important variables.

We agree that we did not report these variables. The summary results of the durations of employment at these factories and the daily working hours were added to the first paragraph of the results.

Discussion

Overall, discussion is very generic.

In the first para, authors have listed a number of specific chemicals which could be presented briefly in the introduction.

We edited and rewritten the discussion in response to your feedback.

Line 169: Authors mentioned “age and sex matched control”. There is no matching done in this study.

This was a typo, we corrected it.

Line 172:  (--  percent  and  ---  percent)…please check and correct.

Thank you for showing this. All typos and inconsistencies in the manuscript were checked and corrected.

Limitations

Please also talk about possible "healthy workers effect". What about lack of information about occupational history of both the groups such as duration of work ...previous exposures ..household characteristics. Also discuss small sample in terms of power and representativeness.

Thank you for your suggestions and comments. We changed and entirely rewrote the paragraph about study limitation based on your feedback.

Reviewer 1 comments:

Authors’ Response:

The authors of this study have improved the text substantially, and explained a lot of issues that were not clear in the previous version of the manuscript. However, some information is still not given clearly. The new text tells details suggesting that the results given are not valid, and absolutely not be used to advise on preventive issues at these types of workplaces (as the authors suggest in their conclusion). The reasons are that:

Thank you for your time and input. We added more details to the introduction, methodology, and discussion. We hope it has improved since then.

-Few workers participated (28) and were compared with 66 healthy workers. There is no information about the size of the population in the 3 factories, and the selection of the production workers is not described. Workers with health problems are more likely to participate in such studies, and if that was the case here, this may have affected the results. The selection of workers is not described, and this issue is not discussed in the discussion.

Thank you for reinforcing this point. We elaborated further on the study's participants. In reality, we chose every employee at each of the three factories. We hope this is now clearer.

-The participants in the comparison group were chosen using exclusion criteria which did not seem to be similar for the detergent factory workers and may have led to a selection of healthier workers in the comparison group. People with for instance lung disorders as asthma were excluded from the comparison group. This makes it unsure whether the differences between these 2 groups are due to selection issues – and might not be due to any difference in exposure.

Sorry that this point wasn’t clear. In fact, we used the same exclusion criteria for both groups. We revised the section on eligibility criteria in the methods section. We hope it is clear now.

-There is no description of exposures of the factory workers from the production of cleaning agents. The manuscript only has some listing of possible chemical cleaning agents in the world without any description of what is produced in the factories of this study. This makes it impossible to interpret any results.

We added a description of the workers in this study and their responsibilities in the factories, which provides us an indication of their exposure.

-The information from the spirometry is not optimally explained. Table 2 gives the impression that the lung function parameters are very good for both groups? FVC is 4.5 for detergent factory works and 4.3 for comparison group. However, the results in table 2 are not clear. It is needed to state what the measures are: Liter? Milliliter? Percent? Also, there are puzzling figures in table 2, since for instance FEV1/FVC is supposed to be written like

this: 0.XX. 90.3 is not a figure to be given for this ratio, this is wrong. Was it meant to be 0.90? Also, when you give this measure, we would like to know how many people have a value below 0.7 – that is

a measure that indicates lung dysfunction.

PEF is most often measured in ml – and PEF%, what is that?

We defined the parameters in the methods section and made some changes to table 2. We hope they are clear now

These unclarities makes one suspect that the authors do not have sufficient competence to describe and evaluate the spirometry results, and the authors are advised to find competent people to help on this issue. All in all – the study has many major flaws and it is difficult to interpret. To give conclusions and suggest how to improve work places, much more information must be given and larger, stronger studies must be performed.

We consulted a pulmonologist and made some changes in the manuscript.

Introduction: It is important to focus this text on work during production of cleaning agents, not work when using cleaning substances. The study is about detergent factory workers. Therefore, the text in the introduction referring to studies of cleaners – those workers that clean and use cleaning agents – are not very relevant here. On page 2, line 51-62, the authors write about cleaners, not the producers, and this part ought to be deleted/rewritten. The reference no. 8, 9 and 11 are about cleaners -not producers of cleaning agents. Ref. 10 concerns general issues on asthma, not production of cleaning agents. There is not much literature about workers production cleaning agents – or it is quite old. You bring in 2 later, no 15 and 16, and should concentrate on these and not include irrelevant references.

I suggest referring to for instance the data sheet ILO has produced on Detergent and disinfectant manufacturing worker https://www.ilo.org/wcmsp5/groups/public/---ed_protect/---protrav/---

safework/documents/publication/wcms_185871.pdf

This data sheet gives basic information about the issue you write about.

Thank you for your suggestions and sharing with us the International Labor Organization fact sheet outlining the risks and preventative measures associated with this occupation. We added a paragraph describing more in details the production process and the risks are the workers prone to. The literature on this subject is limited, and we did our best to locate solely studies on detergent workers. We added the results of research conducted on other populations, such as cleaners, to demonstrate the severity of this problem and to indicate that employees may experience even worse consequences than those exposed to these compounds. In the same context, Study No. 10 refers to the negative results that may occur for those who are exposed to these substances.

Ref 17 is not relevant either, this is about a group of 312 small industry workers, mainly mechanics, welders and painters. A few cleaners might be included in the study, but production of detergents is not mentioned. You should delete the sentence on line 83-85 concerning this.

We deleted the sentence on line 83-85 concerning this point.

Discussion: The first paragraph is far off the reality as it gives conclusion that the study adds to evidence. The following text suggests that work in the detergent factory decreases the lung function parameters. This cannot be stated based on these results.

Thank you for drawing our attention to this. The first paragraph of the discussion has been updated to reflect your comments. We hope it is more appropriate now.

Reviewer 3 comments

Authors’ Response:

I am thankful to the authors for considering my comments/suggestion and making changes in the manuscript. Authors have adequately all the comments and made revisions. Just one minor comments;

The figure 1 better be removed as it duplicates the table 2. It is not advised to repeat the same information.

Thank you for taking the time and making the effort. The figure was added on the request of another reviewer, and we primarily provided some of the most important information. The figure does not include all of table two.