Sedentary behaviour levels in adults with an intellectual disability: a systematic review protocol

Background: Sedentary behaviour contributes to non-communicable diseases, which account for almost 71% of world deaths. Of these, cardiovascular disease is one of the largest causes of preventable death. It is not yet fully understood what level of sedentary behaviour is safe. People with an intellectual disability have poorer health than the general population with higher rates of multi-morbidity, obesity and inactivity. There is a paucity of evidence on whether this poorer health is due to sedentary behaviour or physical inactivity. This systematic review will investigate the sedentary behaviour levels of adults with an intellectual disability. Method: The PRISMA-P framework will be applied to achieve high-quality articles. An extensive search will be conducted in Medline, Embase, psycINFO and Cinahl and grey literature sources. All articles will be independently reviewed by two reviewers and a third to resolve disputes. Initially, the articles will be reviewed by title and abstract and then the full article will be reviewed using stringent inclusion criteria. All article data will be summarised in a standardised tabular format. The National Institute of Health’s quality assessment tool will be used to assess article quality. GRADE will be used to assess the quality of the evidence. The primary outcome of interest is the prevalence of sedentary behaviour levels for people with an intellectual disability. The definition of sedentary behaviour to be used for the purposes of this study is: ‘low physical activity as identified by metabolic equivalent (MET) or step levels or as measured by the Rapid Assessment of Physical activity questionnaire (RAPA) or the International Physical Activity questionnaire (IPAQ) or sitting for more than 3 hours per day’. Conclusion: This systematic review will provide a critical insight into the prevalence of sedentary behaviour in adults with an intellectual disability.


Rationale
According to the World Health Organisation (WHO, 2013), non-communicable diseases account for almost 71% of world deaths. Non-communicable diseases are non-infectious and chronic but can be prevented. Of these, cardiovascular disease (CVD) is one the largest causes of preventable death worldwide with over 17.9 million dying annually. CVD can manifest as increased blood pressure or elevated blood lipid levels, leading to heart attack or stroke. One of the main contributors to CVD is lack of physical activity (Forouzanfar et al., 2016). Physical activity is any bodily movement which uses skeletal muscles and results in energy expenditure (WHO, 2019) while a sedentary lifestyle is one which has low levels of physical activity and consequently low levels of energy expenditure. In general, people with intellectual disability (ID) have poorer health than their non-disabled contemporaries (Emerson et al., 2016) and often experience health disparities (Krahn & Fox, 2014). However, the real state of the science regarding sedentary behaviour and people with ID is not known. Further investigation is essential to understand if sedentary behaviour contributes to these health differences.
It is necessary to understand some of the known contributors to CVD, obesity and physical inactivity, as well as sedentary behaviours because these are all modifiable and inter-related health risks factors.

Sedentary behaviour. Sedentary comes from the Latin word
sedere which means to sit and can describe a wide range of distinct activities which require low levels of energy expenditure in any setting (Thorp et al., 2011). The first real attempt to define the term 'sedentary' was made in 2012 (Tremblay et al., 2017). This was in an effort to avoid confusion by standardising the terms to refer to sedentary or inactive behaviours used in journals. A metabolic equivalent (MET), known as the resting metabolic rate, is an objective measurement scale used to classify activity types and levels. A MET is the amount of oxygen (O 2 ) burned at rest and is the equivalent of 3.5ml O 2 per kg body weight per minute (Jette et al., 1990)

Amendments from Version 1
A reference to the Westrop Systematic review on physical activity and sedentary behaviour in people with an intellectual disability (Westrop et al., 2019) has been included in the introduction section of this protocol. In addition, the National Institute Health (NIH) tools for observational, cohort, cross-sectional and randomised controlled trials have been included in the extended data and the tool for assessing systematic reviews removed. A reference that shows all quality assessment tools by the NIH is also included. Furthermore, the criteria for RCTS has been added to the table. The wording has been changed to highlight that the tools being used for quality assessment are validated tools. Of concern is that Ireland is one of the least active countries in Europe (Loyen et al., 2016).

Physical inactivity and people with ID
For People with an ID, the amount of moderate PA done, and the number of hours spent watching TV was found to be significantly associated with obesity level (Hsieh et al., 2014).

Methods
PRISMA-P, for the reporting and development of systematic review protocols is used as the guide in the writing of this protocol (Shamseer et al., 2015). The completed PRISMA-P checklist for this protocol is available as extended data (Lynch, 2020).

Eligibility criteria
The criteria for inclusion in the review are as follows: • Population: adults aged 18+ with an Intellectual Disability The criteria for exclusion in the review are as follows: • Population: Children with or without an ID and Adults without ID • Language: Articles that are not available in English • Study design: Any type of reviews • Conference proceedings and published conference abstracts only

Information sources Databases
The following four databases will be used to perform the search:

Medline
Embase psycINFO Cinahl In addition, the following sources will be explored for grey literature sources: The

Search strategy
The search strategy was refined into two concepts following the application of PICO. Concept 1 is 'Sedentary behaviour or inactivity' and Concept 2 is 'Intellectual Disability'. Each of the two concepts will be searched using MESH terms and keywords and then combined using OR. Then the total results of each concept will be combined using AND (See Figure 1). This search will be repeated for each of the four databases. The resulting article list will be the complete combined database search results. This list will be screened for inclusion.

Search string.
An example of the search string used for the Medline database is shown in Table 1.
Screening process. All identified articles from each database that is searched, as well as all grey literature sources, will be combined and duplicates removed. Endnote software will be used to store all the identified articles. The articles will be stored in folders which are named after the search process used. Using the inclusion criteria as detailed above, all articles will initially be screened by title and then by abstract. The remaining full text articles will be retrieved and read thoroughly. Those that do not meet the inclusion criteria will be omitted. The remaining articles will then be quality assessed using two separate   assessors with a third person as an adjudicator should any discrepancies arise.

Quality assessment and risk of bias.
The remaining articles will be assessed using two validated quality assessment tools from the National Institute of Health (National Institute Health, 2020), the first for observational cohort and cross-sectional studies and the second for randomised controlled trials (RCTs).
The tools used are available as extended data (Lynch, 2020).
These tools are used to critically assess the internal validity of each article and identify any issues or sources of potential bias. According to Cochrane, effectively evaluating the quality of a study is done by looking at its design, methodology, results, analysis and reporting, and how they relate to the original research question (Higgins et al., 2011).
There are different types of study quality assessment tools for the different study types. For Controlled Intervention Studies and Observational Cohort and Cross-sectional studies, 14 criteria are used to evaluate the study quality, while for Case-Control studies 12 criteria are used. 11 criteria are used to determine the study quality of RCTs. This means that a maximum quality score of 11, 12 or 14 can be achieved depending on the study type. This quality score will be used to determine if the study should be included in the review. Quality scores are divided into 3 main categories: Good, Fair or Poor. See Table 2 for details.
Any studies that are excluded will be tracked with reasons for rejection.

Quality scoring
Scores are attributed to distinct parts of the study design for example type of study, design and blinding, where a 'yes' answer gives a score of '1', a 'no' answer a score of '0' and could potentially highlight an issue with the article. See Table 3.

Ethics
This research project is part of the IDS-TILDA project. Full ethical approval for IDS-TILDA has been granted by the Trinity College Dublin Faculty of Health Sciences Research Ethics Committee.

Study records Data management
All search records will be kept in an excel spreadsheet detailing the database, type of search (keyword or MESH terms) and the resulting search numbers. The articles will be stored in Endnote. Each stage of the search and review will be recorded in excel. For each stage of the search process, articles will be stored in an appropriately named folder in EndNote X9 for windows.

Selection process
The selection process of studies for inclusion, which are identified by the search strategy, will be done by two independent review authors [LL and EB]. The initial screening will be done by title and abstract. If eligibility is inconclusive from the title and abstract, the full text of the article will be assessed. Any articles that do not match the inclusion criteria will be excluded. Any differences on article inclusion between the two authors will be resolved by discussions with the third review author [MMc]. Finally, the full-text article of all potential articles that could be included in the review will be independently assessed by the authors for inclusion as above.

Data collection process
An excel spreadsheet will act as the data extraction tool. This will be used to summarise all the shortlisted studies. The categories to be captured are as in

Outcomes and prioritisation
The outcomes of this investigation into sedentary behaviour will determine the sedentary behaviour levels of older adults with an intellectual disability.

Data synthesis
If quantitative studies are homogenous in nature a metaanalysis may be performed and a forest plot produced to summarise results. A narrative synthesis will be used to summarise all the study article data and relevant information. For qualitative studies, a thematic analysis of the semantic and latenttopics of the articles using a 6-step process (see Table 5), will guide the derivation of a framework for the analysis of the outcome data (Braun & Clarke, 2006).
Statistical comparisons of article data will be reviewed on a case-by-case basis.

Confidence in cumulative evidence
The GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach will be used to assess the strength of the body of evidence of the review. In line with the Cochrane methodology, each outcome will be ranked according to whether the quality is high, moderate, low or very low. The GRADE framework will be used to assess each outcome in the following areas: risk of bias, consistency of effect, imprecision, indirectness and publication bias (Schünemann et al., 2019).

Dissemination of information
The dissemination plan will be to present at conferences for example the THEconf March 2021, Irish Gerontology Society PhD event and other ID or physical activity events or conferences as well as publishing in journals.

Study status
Searches are currently in progress.

Conclusion
This systematic review of the sedentary behaviour levels of older adults with an intellectual disability will provide a critical insight into the sedentary behaviours of this population group.

Open Peer Review
I think that the application is well written and clear despite being very similar to the Westrop work which was published last year. The field of ID is a small one and I imagine that there are not sufficient new works to lead to any differing conclusions than those of Westrop. However, I understand that the HRB are keen to support reanalysis of literature and therefore indexing of this protocol may be justified.
Thank you for inviting me to review this work.