Section

Information you need to report. Ask yourself these questions for guidance

TITLE

Do sugar-sweetened beverages cause adverse health outcomes in children? A systematic review protocol

Identify the report as a protocol for the type of review you're conducting (systematic, scoping, rapid, etc.). 

This protocol has been registered in PROSPERO CRD42014009641.

Where did you register your protocol? OSF? PROSPERO? Other? 

AUTHORS

Alana Smith, Maria Tassia, Emily Moor, Brian House, Matt Tennant, Daniel Mallard, Ronald Ruth & Darth Vader Contact: darth.vader@starwars.com

Who is conducting the review? Who is part of your team? List all contributors and their roles. 

AS, EM, BH, MT, and DM drafted the protocol. AS, RR, DV, MT, NH, RR, reviewed the draft critically and provided important feedback on the content. DM is the guarantor. All authors approved the final manuscript.

What did everyone do? A helpful tool to determine contributions in an unbiased way is to use the CRediT tool

SUPPORT

Dr. Vader has received funding from the Canadian Institutes of Health Research (CIHR) Knowledge synthesis grant AABCD12345 to conduct the systematic review. The funder was not involved in the design of the protocol or decision to submit the protocol for publication, nor will they be involved in any aspect of the conduct of the systematic review. 

Who's the review funder/sponsor? What's their role in the review?

INTRODUCTION

RATIONALE

Chronic diseases, such as cardiovascular disease and type 2 diabetes, impose significant burden to public health. Most chronic diseases are associated with underlying preventable risk factors, such as elevated blood pressure, obesity, and tobacco usage. Sugar-sweetened beverages are known to be significant sources of additional caloric intake, and given recent attention to their contribution in the development of chronic diseases, a systematic review is warranted. We will assess whether the consumption of sugar-sweetened beverages in adults is associated with adverse health outcomes and what the potential moderating factors are.

What's your reason for producing the review? What are you trying to achieve? What gap in knowledge is this covering?

OBJECTIVES

The objective of the systematic review is to answer the following research questions:

In adults, does the consumption of sugar sweetened beverages (SSB) cause adverse health outcomes? 

What specific question is your review addressing? Identify the participants, interventions, exposure, issue, comparators & outcomes.

METHODS

ELIGIBILITY CRITERIA

Study design

We will include randomized controlled trials (RCTs), including cluster RCTs, controlled (non-randomized) clinical trials (CCTs) or cluster trials. We will exclude case reports, conference proceedings, commentaries, letters to the editor.

Participants:  We will include studies examining adult populations, 18 years or older.

Exposure

We will use the Centers for Disease Control and Prevention (CDC) definition of SSB for drinks that should be included. These include:

• Sodas, pop, soft drinks, soda pop
• Fruitades, druit drinks, fruit punches, iced teas, coffees, smoothies
• Energy drinks, fortified waters, sports drinks
• Flavoured/sweetened milk or milk alternatives (dairy, soy, almond, oat, pea)

Outcomes

• Heart disease
• Overweight/obesity
• Type 2 diabetes

Language

We will include articles reported in the English and French languages.

What criteria are you using to include and exclude studies from your review? E.g. Study design, setting, time frame, date, language, publication status, participants characteristics?

INFORMATION SOURCES 

Electronic searches

A comprehensive literature search  will be conducted in OVID MEDLINE®, OVID Embase, EBSCO CINAHL, OVID PsycINFO®, and The Cochrane Library. Electronic search strategies will be developed by a health sciences librarian and peer-reviewed according to the peer review of electronic search strategies (PRESS) guidelines. The search will not be restricted for time period or the language of publication. 

Grey literature sources, such as websites listed within the Canadian Agency for Drugs and Technologies in Health’s (CADTH) Grey Matters checklist, will be searched, and searches documented. 

The search strategy can be found in Appendix A.

What information sources are you gathering information from? E.g. list the databases, study authors, trial registers and grey literature & the dates of coverage you're searching. 

If you have a draft for your search, provide it in an Appendix.

STUDY SELECTION PROCESS

Search results will be de-duplicated in EndNote before uploading to Covidence, an online program that facilitates screening and data extraction. Screening questions will be developed and pilot-tested with a subset of records before implementation. All titles and abstracts of records will be screened by independent reviewer pairs for inclusion and exclusion. Full-text reports for all potentially relevant records and those without an available abstract will be screened by two independent reviewers. Discrepancies will be resolved by consensus or a third person. The study selection process will be reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram, including reasons for excluding full-text articles.

What will your process for selecting studies entail such as having two independent reviewers? Describe the process for EACH phase of your review (e.g. screening, eligibility & inclusion in meta-anaylsis)

DATA COLLECTION AND MANAGEMENT

Data extraction forms will be developed and pilot-tested. Data will be abstracted by independent reviewer pairs, and disagreements will be resolved by consensus or by a third team member, if needed. Information on the descriptive and quantitative characteristics of studies will include the following:

•  Publication details (e.g. year of publication, language, publication status)
•  Characteristics of study (e.g. study design, methods, country, setting, sample size, etc)
•  Characteristics of population (e.g. age, gender, ethnicity, etc)
•  Details about the exposure (e.g. type of added sugar, intervention, etc)
•  Outcomes of interest (definitions, measurement methods, data, adjusted effect, etc)
•  Risk of bias items

How will you extract data from reports? How will you obtain & confirm data from investigators? 

How are you going to manage your records & data during your review process?

List & define all outcomes for which data will be sought, including prioritization of main & additional outcomes, with rationales.

RISK OF BIAS 

Assessing the risk of bias

The risk of bias for each included study will be assessed by one member of the research team and verified by a second member. Disagreements will be resolved by consensus or by a third team member, if needed. We will use the Cochrane Risk of Bias tool will be used to evaluate RCTs. We will follow the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidance for determining the extent of the risk of bias for the body of evidence. 

How will you assess risk of bias in individual studies (will this be done at outcome or study level or both)? 

DATA SYNTHESIS

Study characteristics will be summarized narratively in the text and shown in summary tables in the report. Before meta-analyses are performed, studies will be assessed for heterogeneity on clinical and methodological characteristics; we plan to review these decisions with the research team before conducting analyses. For outcomes that can be measured on various scales (e.g. quality of life), heterogeneity of outcome measurements will also be assessed before pooling. With sufficient homogeneity and quantity of data, we will pool studies using standard random effects meta-analytic methods. Narrative synthesis of data will be conducted when quantitative pooling is considered inappropriate (team decision based on the aforementioned issues, such as disparate clinical characteristics of included patients/participants). 

What criteria will the study data be quantitatively synthesized? 

Is there any proposed additional analyses (e.g. sensitivity, subgroup analyses, meta-regression)?

If not a quantitative synthesis (i.e. qualitative synthesis), describe your method for summarizing data.