Socioeconomic Inequalities in Physical Activity and Sedentary Behaviour among the Chilean Population: A Systematic Review of Observational Studies

Round 1

Reviewer 1 Report

The research is well-conducted and the manuscript is well-written. I congratulate the authors on their work. I send a brief suggestion 

Minor corrections

Section: "conclusion". The first sentence has already been mentioned above and should be removed from this section. This section should be more straightforward.

Author Response

We would like to thank the reviewer for your encouraging comments.

Please find attached a document containing our responses.

Author Response File: Author Response.pdf

Reviewer 2 Report

This is a well designed systematic review of the literature on a topic of global interest and a key risk factor (obesity) for numerous health and well-being outcomes. The methods are very appropriate to the aims of the study and they are very well described.  The results, including the tables and figures, are clearly written and provide specific areas for further investigation. Having these data on a Chilean population is an important addition to the literature and may suggest future research in other populations in Latin America.

The biggest challenge for this paper is the relatively small number of studies that ended up in the final sample. However, the authors do a thoughtful job of describing the key factors considered in the quality assessment of the final sample of papers.

Overall, the study addresses an important topic in an understudied population, and it is well designed, clearly written, and provides both methods and results that can lead to future paths of investigation.

Author Response

We would like to thank the reviewer for your encouraging comments.

Please find attached a document containing our responses.

Author Response File: Author Response.pdf

Reviewer 3 Report

Dear authors,

I appreciate the opportunity to review your manuscript. I find the topic of the review very interesting and necessary to improve obesity rates worldwide.

The methodology of the review is very correct and well written, but during the review of your manuscript some doubts have arisen and I would like to share some comments with you.

The abstract starts with the following sentence "Socioeconomic inequalities in physical (in)activity and sedentary behaviours are key mediators to obesity and health socioeconomic inequalities", don't you think that the relationship between these socioeconomic inequalities and diet as risk factors for obesity should be mentioned? Furthermore, you can read that the scientific literature was reviewed until 31 December 2019, but from which year does the search start? And why?

The abstract concludes with the following sentence: "These findings provide insights to public health and physical activity researchers and policymakers aiming to reduce socioeconomic inequalities in PA and SB in Chile and other countries".  The studies reviewed were of low/medium quality. Do you think this is correct? 

Did the reviewed studies define PA, SB and SEP in the same way as they do in your manuscript? If not, biases may appear and the scientific quality of the review conducted is diminished.

Don't you think that eliminating dietary intake results may lead to a bias in the interpretation of your results?

The articles found and selected for this review do not define SEP in the same way. Some articles study differences in educational level of mother, fathers, employment, household income, ... Do you think their results can be interpreted in a similar way?

The discussion should be written in a more orderly way. It is difficult to interpret. For example, the paragraph starting on line 380 should be at the beginning of the discussion, as they talk about their results.

The paragraph on line 223-232 is written in italics. Why use italics?

On line 312 the following sentence appears: "Our findings suggesting a consistent lower LTPA among the lower SEP groups agree with several reviews of articles among adults from Europe and Western-developed countries". This is contradicted by line 305: "However, inconsistent associations between SEP and total PA, MVPA, transport, transport-related PA, and work-related PA, and low PA were observed".

In line 314 the following sentence appears: "Moreover, our study reporting that adults from lower SEP engaged more in physical inactivity is a novel finding, not observed in the aforementioned reviews". Like the previous comment, this sentence may contradict the sentence on line 305.

Could the gender difference related to PA and transport-related PA be due to the fact that many women are housewives? There is data on this difference.

Obesity is related to PA and SB, but can obesity also lead to a decrease in BP and increase in PB, because of related limitations? It would be interesting to add something on this point, mentioning that the relationship is twofold.

In the conclusions, it should be added that these policies should also pay attention to diet, especially access to food for populations with low socio-economic levels.

As a conclusion: the topic is very interesting, but excluding diet and the causal relationship of PA, SB and SEP in the onset of obesity reduces the applicability of its results in the implementation of health and social policies. However, with some modifications it could be a starting point for an intervention study in different populations.

Kind regards.

 

Author Response

We would like to thank the reviewer for your encouraging comments.

Please find attached a document containing our responses.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Dear authors,

after reading the responses to the comments made in the first revision, I do not feel that the manuscript has improved to be accepted in its current format.

The manuscript does not provide evidence that improves on what has already been published. It seems a starting point for future study. 

The authors' previous publication in another journal on inequalities in access to a healthy diet does not justify that the diet is not present in this review. The absence of this term gives rise to important biases.

The impact of social inequalities on different aspects of society is well known. What evidence or knowledge does your review add to that already published? This question would help to interpret your results and not just be a starting point for further research.

Furthermore, the search period should be restricted, as you cannot compare studies carried out in the 1980s with those carried out today. Access to vehicles, the rise of urban transport, ..., has influenced and influences society and, as a consequence, the physical condition of the population.

Kind regards.

 

Author Response

We thank the reviewer for their comments.

Please see the attachment containing our responses.

Author Response File: Author Response.pdf