PONE-D-20-27905

Changes in contraceptive and sexual behaviours among unmarried young people in Nigeria: evidence from nationally representative surveys

PLOS ONE

Dear Dr. Adedini,

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.

Both reviewers make interesting points regarding the analysis and interpretation of results, which technically is sound. Look, in particular, at comments by reviewer 2, and please adjuts the text accordingly.

Expanding on reviewer 2 comments, there is a change in the analysis that I see necessary. Reviewer 2 points to the difference between males and females, and looking at table 4 we see that behaviour of males and females is radically different. However, the analysis is carried out jointly for both sexes with sex only as a control variable. I don't see this as appropriate. You should fit a different equation for each sex, or, if you prefer so, use a model with full interactions among sex and the rest of variables. That would allow you to test equality of the different coefficients according to sex. It is very difficult to interpret the results from the joint analysis and I don't see a priori any reasons why the effects of covariates should be the same for both sexes when levels are so different. As you know, one of the requirement for publication in Plos One is a high technical standard and this requirement goes in that direction.

One other minor comment: Table 4 does not specify if N is weighted or unweighted. Also there is no information on the kind of weighting applied. It should be normalized weights (average 1).

Please submit your revised manuscript by Nov 09 2020 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

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We look forward to receiving your revised manuscript.

Kind regards,

José Antonio Ortega, Ph.D.

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: Yes

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

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

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: The authors have contributed to an important aspect of sexual and reproductive health (SRH) by looking at the prevailing factors contributing to poor SRH outcomes. The novelty of this work is in no doubt considering the conceptualization, methodology and analysis. However, the author would have employed multi-level analysis; this would have shown the degree of variation within each community of the young people; also, this would have shown other factors that contribute to poor SRH outcomes among young Nigeria as such developing required interventions to address the study conclusion will be targeted to the needed group(s) at different levels, as against socio-demographic characteristics of the respondents alone. Though the technicality of this work is sound, this could be a very good suggestion to employ in the future.

Please kindly check on the manuscript submitted, from lines 56 to 58 about Nigeria being the country with the highest-burden of HIV - You might want to check the literature to be sure.

Also, please kindly check on the manuscript from lines 77 to 81 statement. It appears vague and not passing any message.

Reviewer #2: The manuscript is interesting and has presented the main idea clearly. The subject of this document is relevant and is within the interests of several international organizations that aim to reduce the risks associated to sexual risk behavior in order to achieve SRH-focused objectives. I think the document is on the right track, but it needs major revisions especially on the policy implications.

I include first a couple of comments at the general level and then some more specific ones.

General comments

1. Authors focus their research on the interest on SRH, as it is shown in the Introduction. However, the Discussion has lack of analysis regarding the policy implications and the agenda for policymakers. I expand this comment below.

2. Early sex is defined as having had first sexual intercourse at or before age 14. This is not necessarily the case in this paper. Maybe the authors could make it explicit and show the proportion of the sample falling into this definition. Beyond that, to generalize, author should avoid the term “early sex” and use “sexual debut during adolescence” or “sexual debut before age 18” when referring to this SRH dimension.

3. Nigeria is one of the most populated countries in the world and also one of the highest TFR. Even more, Nigeria is still on the early stage of fertility transition. Besides the potential risk of STIs due to the erratic use of condoms, non-use of modern contraceptives contributes to high levels of fertility. There is research discussing on the benefits of population reduction. Fertility preferences and desires could shape contraceptive use behavior. Authors should account for the high-fertility context of Nigeria at the moment of drawing their conclusions.

4. Author use the terms unmarried and never married as synonyms, although there is a subtle difference. Unmarried includes 4 categories: never married, widowed, not living together, and divorced. It is true that among women aged 15-24 never married and unmarried are quite similar; however, authors should note this difference for further research.

5. Minor language revision and proof-reading before resubmitting.

Specific comments

Introduction

6. From SRH perspective, one of the biggest concerns is unmet need for contraceptives. On the one hand, causes of unmet need are highly correlated to SRH rights violations (barriers to use, gender violence, and social pressure, among others) (e.g., Machiyama et al 2017, doi: 10.1186/s12978-016-0268-z). On the other hand, there is plenty of research analysing the adverse consequences of unmet need (e.g., HIV, unintended pregnancies, maternal mortality). Authors fail to address this issue in the introduction as a context of non-use of contraceptives, even more when unmarried adolescents are at higher risk of having unmet need (Sánchez and Ortega 2018, doi: 10.4054/DemRes.2018.38.45).

7. Authors refer to target 3.7 of the Sustainable Development Goals but they fail to cite it explicitly.

Data

8. Authors should clarify whether they are using never married or unmarried women.

9. Authors present the total number of households of each survey and the sample they are using. However, I would like to know the proportion of the sample compared to the corresponding age group. They could include this information in both Table 2 and text.

10. Authors should include how they have defined “sexually active women”. Having had sex over the last month? Over the last year? Or are they referring to ever-had-sex women as sexually active?

11. Authors are using 2008, 2013, and 2018 DHS “…based on the understanding that a ten-year period is a reasonably long period of time”. By the same logic, a thirty-year period is even more reasonable long period and should be preferred. Why are not they using the 1990 and 2003 DHS? Of course, 1990 DHS does not include men sample; however, they could use 1990-2018 for women and 2003-2018. It is not clear to me why they are not using all available surveys.

12. Religion is included in Table 2 but then left out of the analysis. Why? It would be interesting to observe the influence of religion on contraceptive use behavior.

13. Since secondary/higher education includes roughly 90% of the sample, perhaps the addition of a third category could help show differences by educational level.

Results

14. Table 3 should specify that figures are in percentages.

15. I think that keeping the column “At least one sexual risk” in Table 4, as it is in Table 3, contributes to the analysis. I would recommend to keep the column. The same for Table 5. The multivariate analysis could also be done for “At least one sexual risk”.

16. When analyzing wealth quintiles, I would recommend to use the middle quintile as the base category. Perhaps this will make the differences between quintiles clearer.

17. I would recommend to keep the same order of columns in Table 5 as it is in Tables 3 and 4. It would help to readability.

18. Regarding the results of the logit model, analysis of non-use of modern contraceptives should be expanded.

Discussion

19. I have concerns about the conclusions drawn from the variable "sexual relations before age 18" when comparing the cohorts, as they could be misleading as they are presented now. First, except for those aged 19, all of women of ages 15-19 have had sexual intercourse before age 18 and that is reflected on the estimates of table 5. In other words, the probability of having had sex before the age of 18 for people aged 15 to 19 is practically 1 (so, no surprises there).

Second, adolescents aged 15 to 17 still have several years ahead of them to have their first sexual encounter (taking into account the imposed threshold of 18 years of age). In other words, they have not had the opportunity to complete the exposure period for which the analysis is intended. In this regard, this is why the DHS program does not publish estimates of first sexual intercourse by exact age 18 for those aged 15-19, but it does in the case of by exact age 15.

Authors should find a better (and accurate) way of presenting their results.

20. Authors do not refer at any point about the underlying causes of non-use of contraceptives and inconsistent condom use. As it is now focused, it would be understood that not using modern contraceptives is the result of a negligent decision. However, this is not usually the cases, especially among young people.

It makes me wonder, do women want to use contraceptives? Perhaps they don’t use them because they don’t want them (preferences that could result in high fertility). Or maybe they do not use them because they are not able to get them (unmet need; thus, fail in meeting SRH goals). Depending on the reasons, the policy would be designed.

From there, it would be nice to have some context from other sub-Saharan African countries. From there, authors could compare their result to those found in other countries in the region (e.g., Sedgh and Hussain 2014, doi: 10.1111/j.1728-4465.2014.00382.x; Moreira et al 2019, doi: 10.1186/s12978-019-0805-7).

21. In the cases of unmet need, not using contraceptives usually leads to unintended pregnancy. In adolescence, it is often considered one of the most common burdens of life, responsible for adverse outcomes in adulthood, like reduced labor income, lower educational achievements, or unsafe abortion (e.g., Hindin et al. 2016, doi: 10.2471/BLT.16.170688; Santhya and Jejeebhoy 2015, doi: 10.1080/17441692.2014.986169). Authors fail to discuss the consequences of unintended pregnancy due to non-use of contraceptives, which becomes more relevant in the high-fertility context of Nigeria and in the light of meeting SDG goals.

On the other hand, from a SRH rights perspective, authors should discuss about the importance that adolescents meet their contraceptive needs (e.g., Sánchez and Ortega 2018, doi: 10.4054/DemRes.2018.38.45).

22. There has been little discussion about gender disparities in risky sexual behavior. Results show, first, that women face higher risky behavior than men and, second, it has increased over time. It could give lights about gender violence, especially in recent years (from results in 2018).

23. Statement from line 288 to line 290 contradicts the results presented earlier.

24. I do not agree with the data limitations discussed by the authors:

24.1 Temporality issue: this can be controlled in the regressions.

24.2 Lack of inference of causality: this is not clear to me. Authors are not looking for causality, why should it be a problem?

24.3 Inability to explore other relevant variables outside the data collection framework of the original study: What variables do the authors refer to?

24.4 Recall bias: Authors are using questions reporting on current information and, in some cases, they go back up to 12 months before the survey. Precisely, recall bias is significantly reduced when using the most current information.

I’m not saying that there are no data limitations. I’m only pointing out that I do not agree with those included in the manuscript.

24.5 Finally, in the Introduction authors say SHR policies in Nigeria over the last two decades have been ineffective. I would recommend to discuss on potential solutions.

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Reviewer #1: Yes: Obasanjo Bolarinwa

Reviewer #2: No

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PONE-D-20-27905R1

Changes in contraceptive and sexual behaviours among unmarried young people in Nigeria: evidence from nationally representative surveys

PLOS ONE

Dear Dr. Adedini,

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.

Reviewer 1, who proposed some changes is satisfied. Reviewer 2 has not been invited since they were already willing to accept.  The manuscript has improved to a large extent, and the main concern regards the lack of visibility of the who is unmarried sexually active. These are the minor changes suggested:

• Religion has been added to the analysis but not to table 1.
• Avoid the use of the word “respondents” in discussing table 2, since you are not talking about the characteristics of the survey respondents: the biased characteristics depend on the selection strategy:  never married sexually active. That has to be born in mind in the interpretation of results, which currently is not (lines 174), which should be rewritten after redesign as suggested below.
• As reviewer 1 originally pointed out, this is important for interpretation. The current design of table 2 incorporating the proportion only for the age-group with a different format and a footnote is not satisfactory. Reading the table one wonders why there is an overrepresentation of wealthier / more educated. It could be because of sexual activity or because of selection in marriage, and those go in different directions. Please redesign the table in the following way:
  • Omit absolute numbers, except in the header (as it currently stands)
  • Provide nine columns, three for each survey, including percentages by socidemographic characteristics for the three subgroups of married, not sexually active, and unmarried sexually active (your group of interest). You could include also a chi-square test of association if desired.
  • The interpretation for the first part of results becomes then much more focused: most likely the over representation of wealthier/more educated will be due to lower prevalence of marriage, but there might also be differences in sexual activity. Just rephrase. 
• Line 118: Remove “been” should be “to have ever engaged in sexual intercourse”
• Line 445, 449 highlight higher risk for female, but this is not true for all dimensions (multiple partners goes in the different direction). Please rephrase so that it leads naturally to lines 451-452 saying that SRH policies need to “ account for specific gender peculiarities”.
• Rephrase line 80 as “and pf the adverse consequences of unmet need among young people such as”

Please submit your revised manuscript by Jan 21 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

We look forward to receiving your revised manuscript.

Kind regards,

José Antonio Ortega, Ph.D.

Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

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2. 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 #2: (No Response)

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

Reviewer #2: (No Response)

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

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: (No Response)

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: (No Response)

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6. 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 #2: (No Response)

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Reviewer #2: No

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Changes in contraceptive and sexual behaviours among unmarried young people in Nigeria: evidence from nationally representative surveys

PONE-D-20-27905R2

Dear Dr. Adedini,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

One minor detail that has to be addressed is, in table 2, writing "Ever married" where currently stated "Married". This is in line with the comment made in the original draft by a reviewer suggesting clarification of whether unmarried meant unmarried or never married. I assume it really is "Ever married".

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

José Antonio Ortega, Ph.D.

Academic Editor

PLOS ONE

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