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. 2024 Jun 11;19(6):e0291699. doi: 10.1371/journal.pone.0291699

Cognition, physical function, and life purpose in the rural elderly population: A systematic review protocol

Hércules Lázaro Morais Campos 1,*, Elisa Brosina De Leon 2, Ingred Merllin Batista de Souza 3, Anna Quialheiro 4, Elizabete Regina Araújo de Oliveira 5
Editor: Mahmoud M Werfalli6
PMCID: PMC11166331  PMID: 38861545

Abstract

Introduction

Aging in rural settings worldwide, from the perspective of cognition, physical function, and life purpose essential constructs for a prosperous old age, still needs comprehensive discussion. This systematic review protocol aims to highlight the prevalence of cognitive decline, physical functioning, and life purpose in older adults aging in rural community settings.

Methods and analysis

We will include cross-sectional studies published until April 2023 found in 8 databases: Embase, MEDLINE, LILACS, PsycINFO, Scopus, SciELO, and Web of Science. Ryyan software will be used for the first selection, and the Observational Study Quality Evaluation (OSQE) will assess methodological quality and risk of bias. Primary analysis will involve titles and abstracts using MeSH descriptors such as "Physical functioning," "Cognition," "Cognitive function," "Life purpose," "Elderly," "Older," "Rural aging," "Rural population," "Communities, rural," "Distribution, rural spatial," "Medium communities," "Rural settlement," "Small community." If necessary, secondary analysis will include a complete reading of selected articles by two blinded reviewers, confirmed by a third person. Publication bias will be assessed using cross-sectional analytical study quality. Sensitivity analyses will identify manuscripts significantly influencing combined prevalence of endpoints.

Introduction

Aging within the rural context takes place in various ways globally. The literature increasingly emphasizes that individuals aging in this unique setting exhibit different epidemiological and health indicators than seniors in urban contexts [1].

Controversies arise regarding elderly individuals aging in rural settings, with challenges such as independence, active community participation, safety, housing choice, loneliness, social isolation, service accessibility, leisure, food, transportation, and agriculture until retirement. Conversely, seniors in rural settings may enjoy good health and quality of life, particularly in the cognitive [1] aspect, with better access to health services and healthier living and eating habits, although facing constant frailty risks [2].

Well-conducted cross-sectional and observational studies play a crucial role in aging research, measuring prevalence of health outcomes, understanding social determinants of health, and describing population characteristics [3].

There remains a need for a synthesis of aging in the rural world from the perspective of cognition, physical function, and life purpose. Thus, this systematic review protocol addresses the question: [1] What is the prevalence of cognition, physical functioning, and life purpose in older adults aging in rural community settings?

Methods and analysis

This systematic review protocol adheres to the PICO strategy and is registered with the International Prospective Register of Systematic Reviews (PROSPERO) under number 2022 CRD42022311053.

Eligibility criteria

Databases and search strategy

The search will include cross-sectional studies until April 2023 in journals indexed in health databases: Embase, MEDLINE, LILACS, PsycINFO, SciVerse Scopus (Scopus), SciELO, and Web of Science. Studies epidemiologically evaluating outcomes of cognition, functionality, and life purpose within rural aging and published in Portuguese, English, or Spanish until April 2023 will be accepted. The protocol follows Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines [4].

Search methods

The search strategy will use 3-step Boolean operators and include terms such as "rural aging," "elderly," "old," "physical functioning," "cognition," and "life purpose." The entire search strategy for this systematic review was planned by a librarian and can be found in S1 Appendix. Two independent reviewers (HLMC and EBDL) will conduct the search, with a third reviewer included if tie-breaking criteria are needed.

Study selection and data extraction

After evaluating titles and abstracts from the searches, potential full texts will be assessed for eligibility by two independent reviewers. Authors of possible full texts will be contacted for questions about eligibility criteria. Studies meeting criteria will be included. For studies with the same sample, only those with the most representative example of that population will be considered.

Selected articles will extract data relevant to the theme, including year of publication, authors, characteristics of study institutions, sampling strategy, type of sample, prevalence of outcomes, and associated factors. Information will be organized and presented in tables.

Study evaluation

Methodological quality and risk of bias will be evaluated using the Observational Study Quality Evaluation (OSQE), widely used in the literature for cross-sectional studies [5]. Studies with scores higher than 5 will be included in the discussion.

Strategy for data overview

The synthesis of outcome study data will adhere to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) statement [5, 6]. When two or more articles report results from the outcome database, only the most comprehensive one will be included in the meta-analysis. Results will be presented in Forest Plots, showing 95% confidence intervals and p-values. Heterogeneity will be assessed using the I2 statistic, considering it high when I2 equals or exceeds 75%. Statistical procedures will be performed in STATA 14.0, with a significance level set at 5% for two-tailed tests [6].

There is no direct patient or public involvement in this study.

Ethical approval is not required, as no personal or private information of individuals will be involved. The intention is to submit this study to a peer-reviewed academic journal.

Cross-sectional studies, while economically feasible and easy to conduct, provide preliminary evidence to support more advanced studies. They offer insights into prevalence and incidence, generating essential hypotheses, and can establish possible associations with exposures or risk factors, whether analytical or descriptive [3].

The functional physical capacity of older people aging in rural settings appears better understood, with older women of good incomes more likely to be sedentary than older men [6]. Studies demonstrate factors associated with frailty in rural elderly, including age, gender, health status variables, self-perception of health, number of chronic conditions, disability in basic activities of daily living (ABVD), disability in instrumental ADLs, length of stay in the chair, and psychosocial problems. Depressive symptoms and cognitive impairment are notable, with increased comorbidity and disability in this population [7].

Regarding cognition, literature presents divergent views on the impact of the rural environment on aging. Sometimes, it is viewed positively [2], while at other times, not [8, 9].

The purpose of life in rural elderly individuals is still understudied, with limited knowledge about its impact on rural aging. Current literature suggests that the elderly with a purpose of life are more resilient, have less risk for developing dementia, feel less pain and are happier and more functional [10].

There are many questions to be answered about the way of aging in the rural context, and some gaps still need to be filled and understood to understand rural elder aging. After all, is rural aging positive or negative on the cognition, physical function, and life purpose of the elderly population?

Supporting information

S1 Checklist. PRISMA-P checklist.

(PDF)

pone.0291699.s001.pdf (184.4KB, pdf)
S1 Appendix. Complete research strategy.

(DOCX)

pone.0291699.s002.docx (27KB, docx)

Data Availability

No datasets were generated or analysed during the current study. All relevant data from this study will be made available upon study completion.

Funding Statement

Fundação de Amparo à Pesquisa do Estado do Amazonas, EDITAL N. 012/2021 – POSGFE Ms Hércules Lázaro Morais Campos anf Research scholarship from the Amazonas State Research Support Foundation - Brazil (FAPEAM). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

References

Decision Letter 0

Mahmoud M Werfalli

1 Dec 2023

PONE-D-23-25450Cognition, physical function and life purpose in the rural elderly population: a systematic review protocolPLOS ONE

Dear Dr. Morais Campos,

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. Please submit your revised manuscript by the Jan 15 2024 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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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions?

The research question outlined is expected to address a valid academic problem or topic and contribute to the base of knowledge in the field.

Reviewer #1: Partly

Reviewer #2: Yes

**********

2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses?

The manuscript should describe the methods in sufficient detail to prevent undisclosed flexibility in the experimental procedure or analysis pipeline, including sufficient outcome-neutral conditions (e.g. necessary controls, absence of floor or ceiling effects) to test the proposed hypotheses and a statistical power analysis where applicable. As there may be aspects of the methodology and analysis which can only be refined once the work is undertaken, authors should outline potential assumptions and explicitly describe what aspects of the proposed analyses, if any, are exploratory.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable?

Descriptions of methods and materials in the protocol should be reported in sufficient detail for another researcher to reproduce all experiments and analyses. The protocol should describe the appropriate controls, sample size calculations, and replication needed to ensure that the data are robust and reproducible.

Reviewer #1: No

Reviewer #2: Yes

**********

4. Have the authors described where all data underlying the findings will be made available when the study is complete?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception, at the time of publication. 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: No

Reviewer #2: No

**********

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 #1: No

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics.

You may also provide optional suggestions and comments to authors that they might find helpful in planning their study.

(Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: It is challenging and complex to analyze 3 outcomes in only one systematic review. Elderly is not well accepted term; you may use “older” instead. Title is too generic; the outcome can be specified (prevalence?). The search limit (until April 2022 but incongruent with the one presented in the main text) should be updated. COSMIN aims to improve the selection of outcome measurement instruments both in research and in clinical practice by developing methodology and practical tools for selecting the most suitable outcome measurement instrument. Therefore it is not valid for the purpose of this study. A valid one could be: “Quality Assessment Tool for Observational Cohort and Cross Sectional Studies” from the National Institutes of Health. I find not necessary to specify the MESH terms in the Abstract. Perhaps this sentence then is not any more necessary (because repetitive): “Publication bias will be assessed using cross-sectional analytical study quality”. The Intro is too brief; the topic can be more deeply presented as well as the justification of the study (what is already known or published? Similar reviews?). You should consider stating in methods that you followed PRISMA-P. The search equations for every database should be presented. Regarding inclusion criteria, how “rural elderly” will be classified/identified?

The authors can describe where all data underlying the findings will be made available when the study is complete.

The manuscript needs a through English review.

Reviewer #2: I am grateful for the opportunity to review a study with such a relevant topic.

I suggest that the search strategy specified per database be added.

I suggest that the authors describe where all the data underlying the findings will be made available when the study is completed.

Yours sincerely.

**********

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Reviewer #1: No

Reviewer #2: Yes: Marcus Fernando da Silva Praxedes

**********

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PLoS One. 2024 Jun 11;19(6):e0291699. doi: 10.1371/journal.pone.0291699.r002

Author response to Decision Letter 0

19 Feb 2024

Greetings

Here is our article with all the changes that have been suggested.

Yours sincerely.

Hércules Lázaro Morais Campos

Attachment

Submitted filename: Response to reviewers.pdf

pone.0291699.s003.pdf (12.1KB, pdf)

Decision Letter 1

Mahmoud M Werfalli

26 Apr 2024

Cognição, função física e propósito de vida na população idosa rural: protocolo de revisão sistemática

PONE-D-23-25450R1

Dear Dr. Prof. Hércules Campos

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.

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,

Mahmoud M Werfalli, PhD

Academic Editor

PLOS ONE

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions?

The research question outlined is expected to address a valid academic problem or topic and contribute to the base of knowledge in the field.

Reviewer #3: Yes

**********

2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses?

The manuscript should describe the methods in sufficient detail to prevent undisclosed flexibility in the experimental procedure or analysis pipeline, including sufficient outcome-neutral conditions (e.g. necessary controls, absence of floor or ceiling effects) to test the proposed hypotheses and a statistical power analysis where applicable. As there may be aspects of the methodology and analysis which can only be refined once the work is undertaken, authors should outline potential assumptions and explicitly describe what aspects of the proposed analyses, if any, are exploratory.

Reviewer #3: Yes

**********

3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable?

Descriptions of methods and materials in the protocol should be reported in sufficient detail for another researcher to reproduce all experiments and analyses. The protocol should describe the appropriate controls, sample size calculations, and replication needed to ensure that the data are robust and reproducible.

Reviewer #3: Yes

**********

4. Have the authors described where all data underlying the findings will be made available when the study is complete?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception, at the time of publication. 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 #3: Yes

**********

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 #3: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics.

You may also provide optional suggestions and comments to authors that they might find helpful in planning their study.

(Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #3: The modifications made by the authors between the original version and the revised version are sufficient to ensure a high standard of rigor and transparency.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #3: No

**********

Acceptance letter

Mahmoud M Werfalli

16 May 2024

PONE-D-23-25450R1

PLOS ONE

Dear Dr. Morais Campos,

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on behalf of

Dr. Mahmoud M Werfalli

Academic Editor

PLOS ONE

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 Checklist. PRISMA-P checklist.

    (PDF)

    pone.0291699.s001.pdf (184.4KB, pdf)
    S1 Appendix. Complete research strategy.

    (DOCX)

    pone.0291699.s002.docx (27KB, docx)
    Attachment

    Submitted filename: Response to reviewers.pdf

    pone.0291699.s003.pdf (12.1KB, pdf)

    Data Availability Statement

    No datasets were generated or analysed during the current study. All relevant data from this study will be made available upon study completion.

    Articles from PLOS ONE are provided here courtesy of PLOS

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