PONE-D-20-29562

Individual and community-level determinants of infant mortality in Ethiopia

PLOS ONE

Dear Dr. Kiross,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

This is a very interesting paper. The text is clear, but it needs some revision as detailed by the reviewers. Based on the reviewers' comments and my own reading, I believe the paper could improve the contextualization of the problem and provide more detailed on the variables included in the model, please, provide a brief comment explaining what they are exactly capturing, and the expected results.

A few important issues, that could be clarified, are regarding the methodology: a) please, explain in more detailed the exclusion of some community level factors, more detailed on the estimation of ICC and PCV for the logistic models. I would like to see more information on the presentation of each model. It is my understanding that the modeling strategy should first estimate a model that allows  to decompose the variance between the levels of analysis was presented. It does not include explanatory variables, and the error terms act only on the dependent variable, allowing the partition of the total variability found in the data according to the levels of analysis. Based on the null model, more models could be developed, as there is great heterogeneity in the dependent variable. Was that the approach followed? 

Please, see detailed comments by the reviewers and also the attached file. 

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Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: I Don't Know

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3. Have the authors made all data underlying the findings in their manuscript fully available?

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Overall Assessment: The manuscript is well conceived and executed and makes an important contribution to understanding the underlying causes of infant mortality in Ethiopia.

Introduction:

The authors state that the Ethiopian Demographic and Health Survey (EDHS) 2016 has been analyzed for infant mortality before by other researchers. However, they make the case that all earlier studies have examined individual level factors only and did not pay sufficient attention to community level factors. The authors argue, convincingly why other studies failed to take into account shared community level characteristics, which make a significant contribution to high infant mortality rates; they rightly say that these need to be taken into account when considering infant mortality rates, given the objectives attaining SDG 3 goals of reducing infant mortality rates. The literature review section on this aspect is thorough and point to numerous community level factors that should be taken into account while discussing infant mortality in Ethiopia.

Materials and Methods

The method section is straight forward and clearly written, describing the study variables and the community characteristics. While Table 1 appears to be very cumbersome, all the information Is there. The table captures information pertaining to parameters for analysis, including, antenatal care, place of birth, number of adverse pregnancy events, skilled delivery (referring to a doctor, nurse or a midwife). Postnatal checkups, tetanus shots, age of partner, household wealth index, distance from health facility. This table also included the community level factors such as region of residence, quality of water available, sanitation facilities, multidimensional poverty indices. These items were recoded for analysis, recoding of these items.

Results and Data Analysis:

The results (tables 2-7) describe the general characteristics of the study population at the individual and community level. The data analyses consist of descriptive analysis section and a multi-stage multivariate analysis. It requires fairly sophisticated analytical skills. Some of the results are consistent with findings by other investigators. However, they have managed to tease out information that is important.

Suggestions to improve readability.

1. Line 85: - which could be introduces a serious bias - is grammatically wrong. It should read as follows: which could introduce a serious bias;

2. Line 111: the last sentence is a bit confusing need to make sure that the reference is quoted correctly;

3. Line 158: replace -that share with who share;

4. Table 1, page 6: there needs to be an explanation of what century day code means in the context of this study;

5. Table 1 Page 7 reported birth size: It cannot be three fourths (3/4ths) of the births but two thirds (2/3) of the births;

6. Table 1, page 7, reported birth size: delete were from the sentence;

7. Table 1, page 7 reported birth size delete were and write gave birth;

8. Table 1, total live births replace much with many;

9. Table 1 page 7: need to pay attention to tense; since past tense was used earlier, I suggest using was instead of is;

10. Table 1: page 8 age of mother instead of mother's;

11. Table 1, Marital status page 8 marital status and not martial status;

12. Table 1, page 8: marital status - it seems that the categories did not follow what was indicated in the text. Suggest rewriting this section to avoid confusion;

13. Table 1, number of adverse pregnancy events, page 8: replace child with infant in this phrase;

14. Table 1, page 9: should this be the last pregnancy? Please clarify

15. Table 1, place of birth, page 9: this phrase needs to be edited: place where mothers gave not give. the word origination needs to be replaced;

16. Table 1, number of adverse pregnancy events, page 10: replace child with infant in this phrase;

17. table 1, skilled delivery, page 10: insert was in this sentence:

18. Table 1, partner age, page 11: were husbands always older than the wife?

19. Table 1, House-hold wealth, page 11: index the correct spelling; this should be principal and not principle;

20. Table 1, distance from health facility, page 11: was instead of were;

21. Table 1, distance from health facility, page 11: rating not rate;

22. Table 1, distance from the health facility, page 12: add after self report

23. Table 1, distance from health facility, page 12: options not option

24. Table 1, distance from the health facility, page 12: delete it from the sentence to read as is.

25. Table 1, region of residence, Page 12: replace who with that

26. Line 204: had instead of have.

27. Line 210: should be - at an age.

28. Line 214: majority of the head of households were males

29. Line 284: delete a

30. Line 287: The authors have only considered female genital mutilation as a contributing factor. They have not considered the impact of male child preference and neglect of female infants. In India for example, female infant mortality or sex ratio favors male infants. Suggest paper by Prabhat Jha https://arthaimpact.com/wp-content/uploads/2019/09/bc574888-cd46-4f7b-afc2-8d024829057b_35.pdf

31. Line 298: Multiple births have a huge impact on the on the health of the pregnant woman during the perinatal period, including deliveries. I wonder if the authors attempted to correlate C-sections with multiple pregnancies.

32. Line 302: insert a comma after the word increased.

33. Line 303: remove was from this sentence

34. Line 305: rephrase the ....lower among women who attended four and more antenatal care visits

35. Line 308: change sentence compared to women (mothers) who had no such previous loss

36. Line 309: I suggest deleting the sentence Studies ...on the survival of the next infant OR add the references to this statement

37. Line 311: I suggest changing the word survivorship to survival. The meaning of biologically and environmentally is not clear in this context. I suggest removing this altogether or provide more explanation as to why there is an environmental concern.

38. Line 314: insert of before breastfeeding

39. Line 316: I am not familiar with maternal depletion syndrome please include a description.

40. Line 323: do you mean 4.1% instead of 41.%?

41. Line 324 and 325: This sentence needs to be fixed, it is not grammatically correct

42. Line 326: I suggest changing the sentence to - but much higher than- instead of and also much higher compared to other African countries.

43. Line 327-329: these data seem a bit random since not all regions are compared with respect to family planning, immunization coverage and access to hospitals between Tigray, Somali and Afar regions. Could comparative statistics not be located for all the parameters??

44. Line 330: suggest changing the tense to past tense since that is the format used.

45. Line 336-337: this argument seems logical. However, it seems that there are people who belong to the rich category in this group. Was a separate analysis done for the group considered to be rich in infant mortality group?

46. Line 344: the most important reason why infant mortality is high in the mountainous region is the distance from a health post where any assistance can be given to gravid women. Sometimes women have to walk or be carried physically over very difficult terrain to reach the health post. If there is obstructed labor or needing C-section, neither the woman nor the infant survives the journey. Some acknowledgment of this reality should be included in this text.

47. Lines 350-351 This sentence seems to contradict the main argument made in the paper that both community level and individual level factors affect infant mortality. I suggest modifying the statement somewhat.

48. Line 362-365: This could be a stronger statement than the one presented here. Clearly, as suggested in the paper, community level factors include health infrastructure with availability of health facilities and even antenatal services. These come well within the purview of the SDG goals and deserve a stronger recommendation as a conclusion of the analysis.

Reviewer #2: Overall Impression

The manuscript presents an original idea, well executed, and aligned with the scope and broad audience of the journal. Their results support previous evidence of upstream determinants of infant mortality in the Global South and may be impactful and translatable to actions in the country based on. However, I believe that some aspects of this research should be reconsidered. Therefore, I recommend major revisions for this work.

Discussion of specific areas for improvement

The methodological approach implemented in this study seems appropriate for the research question. However, is not very clear the definitions (stated in table 1) and selection of some individual and community- level factors mentioned in the method section that were not part of the main analysis. On one hand, regarding the definition of access to improved water or sanitation at the community level it is not clearly stated whether these variables are capturing the proportion of population with these conditions or whether this is a characteristic of each household included in the study. On the other hand, there are concerns about collinearity among variables at individual and community level that were mentioned in the method section, such as decision-making authority or wealth/ poverty indexes at both individual and community level. As some of these variables were not included in the main analysis, it is important to rule out whether the exclusion correspond to a lack of real association or non-observed effect due to collinearity or incorrect definition of its hierarchical level.

The units of analysis described in the method section correspond to 10,641 children 0-5 years old, while descriptive tables 2-6 are based on (apparently) the number of mothers included in the survey (11,023). I think the authors should clearly state the units of analysis considered and align descriptive tables to this in order to avoid confusion in the readiness of the paper.

Method section needs also to include a brief description of how ICC and PCV measures were calculated for multi-level logistic models as these are different from the way variance component are obtained in linear models.

The study remarks regions as one of the main community-level factors associated to infant mortality. Further in the discussion, the authors explained the potential influence of community-level factors that were not measured in the analysis but considered embedded in the meaning of region (such as access to public services different across regions) on infant mortality. I think that assessing interactions between regions and some individual-level characteristics could bring a more refined approach to the interpretation of these characteristics described in the discussion. If interactions were explored as part of the main analysis and not reported it should be stated in the methods or results section.

Discussion could take leverage of this information to elaborate on the importance of macro- social determinants of infant mortality.

Minor comments

Overall, the manuscript should revise the organization of some sections and tables to improve readability. There are some sentences in the introduction that sounds repetitive (arguments in lines 68-72 are similar to evidence stated in lines 91-94 line 116 similar to 188; 126 similar to 128;) and could be summarized in a more succinct way, which will also allow more room for the description of limitations of previous work in recognizing upstream determinants of infant death and the impact of ignoring this.

Authors should also revise the writing in table 1, being consistent in the way variables are described, and check for missing words/ expression and typos. Tables 2- 6 can be summarized in one table to facilitate the reading. I suggest including in tables 1-6 only variables used in main analysis, to avoid confusion during the reading of the manuscript. Variables considered in previous examination but omitted from main analysis could be referred as supplementary tables.

Edition comments.

Table titles should be reviewed to properly described its contents. Font size should be reviewed throughout tables, and footnote for some marks stated in the tables should be also included

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Reviewer #1: No

Reviewer #2: No

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Submitted filename: Reviiew report for paper.docx

Individual-, household- and community-level determinants of infant mortality in Ethiopia

PONE-D-20-29562R1

Dear Dr. Kiross,

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Kind regards,

Bernardo Lanza Queiroz, Ph.D

Academic Editor

PLOS ONE

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