Mapping behavioural interventions to reduce sugar-sweetened beverage (SSB) consumption among US adults: a scoping review protocol

Abstract

Introduction

Sugar-sweetened beverages (SSBs) are sugary drinks such as sodas, fruit drinks and sweetened teas and are the leading source of added sugars in the American diet. SSBs are also linked to chronic diseases like type 2 diabetes, cardiovascular disease and certain cancers. Despite their well-known health risks, SSB consumption remains high in the United States of America (USA), with 63% of adults consuming them daily, often exceeding the recommended limit of 50 g of added sugar per day. Though efforts to reduce SSB intake through educational programmes, policy initiatives and taxes exist, further research is needed to assess the effectiveness of interventions to reduce SSB consumption in the USA. Understanding the role of behavioural interventions in lowering SSB consumption among adults is critical to address public health strategies.

Methods and analysis

The proposed scoping review will be conducted in accordance with the Joanna Briggs Institute methodological framework for scoping reviews. An advanced search will be conducted in three electronic databases: PubMed, PsycINFO and Scopus. The reference lists of included studies will also be reviewed to identify additional relevant literature. All identified citations will be compiled in EndNote, and duplicate citations will be eliminated. Identification of studies will occur through the three-step search process: (1) initial screening of studies according to inclusion criteria, (2) eligibility determined through full-text assessment and (3) inclusion of qualified studies meeting the criteria. To be included, studies must report on an existing behavioural intervention to reduce SSB consumption. All studies will undergo screening by two independent reviewers. Any disagreements that arise will be resolved through discussion or with an additional reviewer. A data extraction tool has been developed to extract relevant data from all eligible studies. The extracted data will be presented in a diagrammatic form, alongside a narrative summary, in line with Preferred Reporting Items for Systematic Reviews and Meta-Analysis: extension for Scoping Reviews reporting guidelines.

Ethics and dissemination

Ethics approval was not sought as all data will be collected from published literature. We will present our findings at relevant conferences and submit manuscripts for publication in peer-reviewed journals.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• The scoping review will adhere to the Joanna Briggs Institute methodology for scoping reviews, which is a strength.

• Involvement of an experienced senior medical librarian in developing the search strategy was adopted and is a strength.

• As this is a scoping review, there is no plan for a meta-analysis; thus, the review will offer a descriptive mapping of the evidence rather than quantifying effect sizes or statistically comparing outcomes across studies.

• Despite a comprehensive literature search, a limitation is the restriction to studies written or translated in English and conducted in the USA.

• A limitation is the exclusion of grey literature from the review.

Introduction

Sugar-sweetened beverages (SSBs), also known as sugary drinks, refer to any beverage containing added sugar or other sweeteners such as, ‘brown sugar, corn sweetener, corn syrup, dextrose, fructose, glucose, high-fructose corn syrup, honey, lactose, malt syrup, maltose, molasses, raw sugar and sucrose’.^{1 2} Examples of SSBs include, but are not limited to, sodas, fruit drinks, sport drinks, energy drinks, as well as sweetened waters, coffee and tea beverages with added sugars.^{3 4} SSBs have been linked to an increased risk of chronic diseases.⁵ Consuming high quantities of SSBs is associated with weight gain, type 2 diabetes, other cardiovascular diseases and some cancers.⁵ Limiting the intake of SBBs may prevent weight gain and reduce the risk of some diseases.

In contrast to naturally occurring sugars, such as those found in nutritious foods like fruits, vegetables and milk, added sugars refer to syrups and other caloric sweeteners added during the processing of foods.^{2 6} Added sugars are included in foods and beverages to sweeten them, increasing calorie content without providing any nutritional value.² Indeed, SSBs are the leading source of added sweeteners in the American diet.⁷ The Dietary Guidelines for Americans recommend a daily limit of 50 g of added sugars, based on a 2000-calorie diet. However, adults are reporting a higher intake of added sugars.¹ According to data collected in 2010 and 2015 in the National Health Interview Survey, which includes participants from all 50 states, 63% of US adults consumed SSBs once or more times daily.⁸ A single serving of an SSB contains approximately 40 g of sugar, meaning that individuals consuming more than one SSB per day are likely to exceed the recommended daily limit of added sugar.⁹

Despite the well-documented health risks associated with excessive SSB consumption, the prevalence of these beverages in the American diet remains high. This underscores the need for effective interventions to address their consumption. There have been some efforts to reduce SSB consumption in youth and adolescents across various levels of the ecological framework including educational programmes and counselling at the individual and interpersonal levels, policy initiatives in schools and the workplace environment and taxes at the policy level.^{10 11} However, further investigation is needed to better understand how behavioural interventions and policies have impacted SSB consumption rates in the USA, which is crucial for developing and refining public health strategies targeting adult SSB consumption.1012,14 While policy-level changes often have broader and more immediate impacts by influencing environmental and structural factors, behavioural interventions are designed to influence individuals’ health-related behaviours by modifying knowledge, attitude and behaviour toward SSB consumption and therefore, are needed to support and enhance the effectiveness and acceptance of policy changes at a broader level.^{12 15}

Methods and analysis

The proposed scoping review will be conducted in accordance with the Joanna Briggs Institute methodology for scoping reviews.^{16 17} We will undertake the following five stages in the review process: (1) identifying the research question; (2) identifying relevant studies; (3) study selection; (4) charting the data and (5) collating, summarising, and reporting the results.

Additionally, we follow the patient/population, intervention, comparison and outcome (PICO) theoretical approach to formulate and establish a research question in this review (table 1). The PICO framework predefines key components that are necessary to facilitate the search strategy.¹⁸

Table 1. Patient/population, intervention, comparison and outcome (PICO) framework.

Population/patient problem	Intervention	Comparison	Outcomes
US adults who have received a behavioural intervention to reduce sugar-sweetened beverage (SSB) consumption	Family-based behavioural intervention School-based behavioural intervention (with adult outcome) Community-based behavioural intervention (with adult outcome) Individual-based behavioural intervention	Non-recipients of behavioural intervention Pre- and postintervention comparison	Decreased consumption of SSBs Increased consumption of non-SSB beverages (eg, water)

Patient and public involvement

Patients and the public were not involved in the design, conduct, reporting or dissemination plans of this study, as it is a scoping review of existing literature. This review aims to summarise and map the current body of evidence to inform future research and potential patient engagement.

Stage 1: identifying the research question

The objective of this scoping review is to map the existing literature on behavioural interventions targeting SSB reduction among US adults. Specifically, this review aims to: (1) identify the types of behavioural interventions that have been conducted, (2) map the breadth of evidence available on these interventions and (3) highlight gaps in the current research to inform future studies. By synthesising the available evidence, this review seeks to provide a comprehensive overview of the strategies that have been employed to address SSB consumption and their outcomes. To meet these objectives, the following research question was posed:

1. What type of behavioural interventions have been conducted to reduce SSB consumption among adults in the USA?

Stage 2: identifying relevant studies

The search strategy was developed by the research team in collaboration with an experienced medical librarian. A comprehensive search of the literature will be conducted using the following electronic databases: PubMed, PsycINFO and Scopus. PubMed was selected for its extensive coverage of biomedical literature, with over 35 million citations. PsycINFO provides broad coverage of behavioural science literature relevant to the topic. Scopus was included for its interdisciplinary scope across public health, social science and behavioural research, and its strength in indexing recent publications. The search strategy will consist of a controlled vocabulary approach known as Medical Subject Headings (MeSH) and a title/abstract search using selected keywords. MeSH terms and concepts will be combined using Boolean logic and operators. Using MeSH terms and keywords, a search string will be formulated to conduct an advanced search on both electronic databases to identify studies on the topic. A draft search strategy is included in online supplemental file 1). The search strategy was intentionally kept broad to ensure comprehensive capture of relevant studies. The search strategy will aim to identify studies published between 2010 and the date the search is conducted. This review will only include papers originally written in English or papers translated from other languages to English.

Prior to conducting the full search, we will implement a training phase to ensure consistency and reliability among reviewers. This will involve selecting 10 papers that cover a range of topics relevant to the review. Each reviewer will independently review the 10 selected papers using preliminary criteria. Reviewers will meet to discuss their findings and address discrepancies. Based on this discussion, standardised criteria and guidelines will be refined to guide the review of the remaining papers. Adjustments to the review protocol will be made as necessary to ensure consistency and clarity. Following the advanced search, all identified citations will be compiled and uploaded into EndNote. Duplicate citations will be eliminated. Titles and abstracts will then undergo screening by two independent reviewers to assess the inclusion for review.

Stage 3: study selection

Study selection will follow a two-step screening process consisting of a title and abstract screening, followed by a full-text review. In both steps, two independent reviews will screen the articles against the eligibility criteria. Any disagreements that arise between the reviewers at each stage of the selection process will be resolved through discussion, or with an additional reviewer. Sources that do not meet the inclusion criteria at the full-text stage will be documented and reported as excluded in the scoping review.

The review will consider sources of evidence that report on adults (≥18 years of age) who participated in a behavioural intervention to reduce SSB consumption. Participants of the studies assessed must reside in the USA and be fluent in English and/or Spanish. This review will focus on studies that provide behavioural interventions to reduce SSB consumption. It will include various intervention types including individual-based approaches, family-based approaches and dyad methods involving two elements such as mother-daughter or mother-son pairs. Examples of dyad interventions include school-based and community-based programmes, and only those with SSB consumption outcomes for adults will be included.

A behavioural intervention is designed to influence an individual’s actions concerning their health.¹⁵ The primary goal is to change or stop the behaviour (ie, SSB consumption). The review will include studies reporting on a behavioural intervention within any geographic location in the USA. The behavioural intervention can occur in any setting (eg, primary healthcare, schools or the community). Rural, urban and suburban areas will be included. This scoping review will include scholarly and peer-reviewed sources that focus on behavioural interventions. Sources will be considered without restriction to specific study design (eg, cohort study, case-control study, randomised control trial) or methodology (eg, qualitative, quantitative or mixed methods).

Stage 4: charting the data

Two independent reviewers will extract relevant data from all included studies in the scoping review. We will use a structured data recording form developed by the reviewers on a spreadsheet. The extracted data include details on the author; year of publication; title; study participants; geographic location of study; data collected; study design; barriers to access; intervention implemented. A draft data extraction tool is included in online supplemental file 2). The draft data extraction tool will be piloted and revised as necessary during the process of extracting data from each study. Any disagreement that arises between reviewers will be resolved through discussion and consultation with a third reviewer.

Stage 5: collating, summarising and reporting the results

We will report our findings in line with the ‘Preferred Reporting Items for Systematic Reviews and Meta-Analysis: extension for Scoping Reviews’ checklist (PRISMA-ScR). The results will be presented through both a narrative summary description and a PRISMA-ScR flow diagram (figure 1), which will describe how the results meet the objectives and aims of this scoping review. We will provide an overview of target participants, type of interventions implemented, types of studies included and the context of each included study. This review will report research trends and gaps, providing guidance for future interventions.

Figure 1. Preferred Reporting Items for Systematic Reviews and Meta-Analysis: extension for Scoping Reviews (PRISMA-ScR) flow diagram that will be used for study selection process.