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Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
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2

Methodological Approach

The committee held closed and open session meetings to discuss and develop an approach to perform the scoping review to identify and summarize relevant publications on complementary feeding interventions. These interventions were categorized as occurring in health care settings, early care and education (ECE) settings, and university cooperative extension (CE) settings, as noted within its Statement of Task (see Chapter 1), as well as interventions that complemented existing federal programs (e.g., Special Supplemental Nutrition Program for Women, Infants, and Children [WIC] and home visiting programs). This chapter provides the committee’s interpretation of its task and approach to gathering and assessing relevant evidence to inform and support its findings and conclusions.

COMMITTEE’S INTERPRETATION OF THE TASK

The committee interpreted the Statement of Task as a request to scope the literature and use expert judgment to identify promising interventions, or aspects of interventions, that positively impact infant and young child feeding related to what and how to feed infants and young children between 6 and 24 months of age. As noted in Chapter 1, the committee interpreted the Statement of Task to request a scoping review (i.e., provide an overview of the evidence [Munn et al., 2018]) rather than a systematic review (i.e., involving specific questions and in-depth analysis of the strength of evidence using methods such as Grading of Recommendations, Assessment, Development and Evaluations [GRADE] [Guyatt et

Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×

al., 2008]), as the request was to provide an overview of the evidence and not to grade the evidence. The committee commented on strengths and weaknesses of each included article.

The committee reviewed interventions aimed at addressing both what to feed infants and young children (e.g., avoiding foods and beverages with added sugars; offering a variety of foods, textures, and flavors; consuming nutrient-dense foods) and how to feed infants and young children (e.g., using hunger and satiation cues to guide feeding; providing repeated exposures to foods; utilizing other responsive feeding practices). As noted in the Statement of Task, the scoping review targeted interventions conducted in health care settings, ECE settings, and CE settings. At the direction of the study sponsor, the committee also included interventions that complemented existing federal programs targeting at-risk children under 2 years of age and their caregivers that may influence infant and young child feeding behaviors (e.g., the WIC and home visiting programs) and interventions conducted in other settings that otherwise met the criteria for inclusion. Also, at the direction of the study sponsor, the committee interpreted the Statement of Task to include only interventions aimed at improving complementary feeding behaviors, excluding studies aimed at impacting the timing of introducing complementary foods or the duration of human milk feeding.

SEARCH APPROACH

The committee approached its task by designing a literature search strategy to capture public-facing documents, reviews, and resources on interventions aimed at improving infant and young child feeding behaviors in healthy children (see Appendix C for details on the literature search). The approach for the scoping review was developed and refined by the committee during multiple open and closed session meetings.

Search Strategy

The committee used the National Academies of Sciences, Engineering, and Medicine’s (the National Academies’) Research Center as a resource for carrying out the literature search. Guided by the Statement of Task (see Chapter 1, Box 1-1), the Research Center staff created a list of keywords, including all the assigned MeSH and Emtree terms. The committee reviewed the list of terms and provided feedback on the keywords and natural language terms. The research center staff then compiled a literature search strategy based on the Statement of Task and identified keywords. The search strategy was used to search online databases (Medline, Embase, and Scopus) to identify peer-reviewed published literature

Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×

and gray literature. Only English-language articles published between January 2002‒January 2023 were searched. Appendix C provides further details of the search strategy.

Internal Assessment

The committee used an internal assessment to determine whether the search strategy was too narrow. Committee members suggested five to six key articles that they expected to find in the search results. Staff checked whether the search had identified the submitted articles. The search strategy was refined after the internal check through the removal of the “NOT” group of disease terms, therefore broadening the search (see Appendix C). After a new search was conducted, the internal check was redone, and as the audit results were consistent with the expected outcomes, no further refinements were made.

SCREENING AND DATA EXTRACTION

Prior to screening the identified literature, the committee developed a draft set of prespecified criteria for assessing the relevance of identified evidence, which was refined after the initial title/abstract screening. The criteria were organized using the population, interventions, comparators, outcomes, and study designs (PICOD) framework; Table 2-1 shows the final criteria. As a note, the committee excluded interventions done in populations extending beyond 2 years of age when the data analysis was not stratified by ages 0‒2 years. In addition, while screening the literature the committee collected any interventions or protocols of ongoing interventions that were under way (i.e., no results are published).

Screening

The search results were uploaded into a web-based systematic review platform (PICO Portal1) for screening. Of the 63,844 articles identified, 16,520 articles were identified as duplicates, leaving 47,324 articles to undergo title and abstract screening. A title and abstract screening of each retrieved record was performed by two individuals (trained staff from the Health and Medicine Division and PICO Portal) using the pre-specified criteria in Table 2-1. PICO Portal uses machine learning to sort and present first the citations most likely to meet the pre-specified criteria, and, thus, be eligible for further screening (see Appendix B).

___________________

1 See PICO Portal website for further information: https://picoportal.org (accessed July 12, 2023).

Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×

As screening progresses, the machine learning and artificial intelligence system is trained. Once the artificial intelligence obtained a 99 percent recall rate of citations eligible for full-text screening, screening stopped under the assumption that all eligible articles had been captured by machine learning sorting, and if any were missed, they would be less related to the task. Following title and abstract screening, using Table 2-1 criteria, two Health and Medicine staff members screened 185 full-text articles.

Internal Assessment

To verify that the process was working as intended, all members of the committee reviewed the same 30 articles that had not yet been abstract

TABLE 2-1 Prespecified Criteria for Assessing the Relevance of Identified Evidence for Interventions That Improve Complementary Feeding Behaviors in Infants and Young Children

Component Criteria
Populations Include:
Healthy infants/children ages 0‒2 years of age living in high-income countries at the time of studya
Exclude:
Studies in countries other than those classified as high-incomea
Studies in which infants are receiving ONLY human milk or formula
Studies that only included infants/children with one or more existing chronic disease or health conditionb
Interventions Any intervention for complementary feeding (e.g., behavioral/motivational, informational/educational, social media/mass communication, food distribution/allocation/access).
Comparators Different approaches to complementary feeding compared within the same study (e.g., nonreceipt of the intervention in the same population, standard of care).
Study Designs Include:
Randomized controlled trials (individually randomized and cluster-randomized)
Quasi-experimental studies (e.g., before/after studies)
Pragmatic trials (clinical trials conducted in real-world settings)
Implementation science studies
Comparative effectiveness trials
Exclude:
Non-English language articles
Publications from before 2002

a Countries are classified according to definitions from the World Bank: https://data.worldbank.org/income-level/high-income (accessed July 12, 2023).

b This included studies that included only infants/children with developmental delays.

Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×

screened based on machine learning reorganization and confirmed that none of the articles were relevant to the current study. In addition, as a secondary check, a different, randomly selected subset of 30 articles from the pool of articles that were not yet abstract screened were selected and abstract screened by the National Academies staff. None of these articles met the criteria set by the committee (see Table 2-1) either.

Data Extraction

Data extraction was conducted using an Excel spreadsheet and predetermined extraction criteria (see Appendix D). Each article was examined by two individuals: one staff member as a primary data extractor and one committee member as a validator who verified the extracted data. The committee extracted elements needed to map the existing interventions by setting (e.g., setting, population, intervention description, outcomes assessed) and to assess the validity, scalability, and strength of the evidence. The committee focused on outcomes related to infant and young child feeding behaviors and categorized these by what to feed (e.g., avoiding foods/beverages with added sugars; offering a variety of foods, textures, and flavors; consuming nutrient-dense foods) and how to feed (e.g., repeated exposures to foods; using hunger and satiation cues to guide feeding; utilizing other responsive feeding practices). The committee also collected information on additional health outcomes related to feeding behavior, such as anthropometric measurements.

ASSESSMENT OF THE EVIDENCE

The included articles were subdivided by the setting of the study. Settings for the study included the following categories:

  1. Health care settings that influence feeding (e.g., health care centers, federally qualified health centers, doctors’ offices),
  2. ECE settings,
  3. CE programs that include nutrition and feeding for young children,
  4. WIC settings,
  5. Home visiting programs, and
  6. Other settings (e.g., website, video, short message, distribution of written materials, or intervention conducted by a researcher unaffiliated with any of the settings listed above)

More detail about each of these settings is included in Chapter 3. While some studies included more than one setting, interventions were

Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×

categorized by the main location of the intervention. For example, if an intervention involved both a health care setting and a home visit, it was classified based on the model it followed (medical model or home visiting model).

In response to the Statement of Task (see Box 1-1), the articles were further subdivided by committee expertise, and one committee member individually reviewed each article to further examine and assess the relevance and strength of the study. Basic information about each intervention (e.g., setting, population reached, description of the intervention, infant and young child feeding outcomes assessed) and its impact on the outcomes assessed were documented. The committee described considerations that were taken into account when reviewing the evidence (see Chapter 3), commented on the strengths and weaknesses of each individual article and the potential for scalability of the intervention (see Appendix E), and used its collective expert judgment when identifying potentially informative studies. As described above, the committee interpreted the task as a request to undertake a scoping review to map interventions aimed at improving complementary feeding behaviors. Thus, in-depth grading of the evidence was beyond the scope of this report.

After finishing the comprehensive identification of potentially informative studies, and a description of their characteristics, the committee proceeded to assess the studies’ contributions to addressing the Statement of Task. First, the committee determined that there is not any individual program that has all the desired features of an intervention that could simply be adopted as is and scaled to address the challenges of encouraging appropriate infant and young child feeding. Nonetheless, there were important insights to be gained from the body of research that provide a solid empirical foundation for the committee to make informed judgments regarding the key features of effective, scalable programs across settings and systems.

The committee first identified a small number of interventions that are the most broadly informative for developing new initiatives. Although none are without methodologic limitations or universally effective in improving all outcome measures, they provide valuable models to be built on. These designated “Informative Studies” were chosen based on consideration of three key characteristics:

  1. Quality of methods, considering the design, quality of measurement, study size, and other features as reviewed in Chapter 3;
  2. Evidence of effectiveness, namely the evidence that at least some of the key outcomes were influenced by the intervention;
  3. Potential for scalability (i.e., whether the program lends itself to being widely implemented in the United States), considering such
Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×
  1. features as acceptability to recipients, suitability for diverse populations, feasibility within existing U.S. systems, and financial cost.

These considerations could not be quantified and required the committee’s expert judgment, but there were three such programs that provided important information to be considered in reaching its conclusions.

Studies other than those included as Informative Studies also contributed important ideas and insights, on a selective rather than comprehensive basis. Specific findings from those studies offer clear suggestions of features that should be considered for incorporation into a program that is effective and scalable, and those are noted as “Informative Intervention Elements.” For both valuable sources of insight, we provide a brief description of the study (with more detailed information in Appendix E) and focus on the insights that the study contributes toward the committee’s conclusions.

The committee described factors needed to scale interventions to the community or state levels and noted the ability of the interventions to reach underserved populations, reduce inequities, and complement federal-level programs such as WIC and home visiting programs.

REFERENCES

Guyatt, G. H., A. D. Oxman, G. E. Vist, R. Kunz, Y. Falck-Ytter, P. Alonso-Coello, and H. J. Schünemann. 2008. GRADE: An emerging consensus on rating quality of evidence and strength of recommendations. BMJ 336(7650):924–926.

Munn, Z., M. D. J. Peters, C. Stern, C. Tufanaru, A. McArthur, and E. Aromataris. 2018. Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC Medical Research Methodology 18(1):143.

Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×

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Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×
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Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×
Page 30
Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×
Page 31
Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×
Page 32
Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×
Page 33
Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×
Page 34
Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×
Page 35
Suggested Citation:"2 Methodological Approach." National Academies of Sciences, Engineering, and Medicine. 2023. Complementary Feeding Interventions for Infants and Young Children Under Age 2: Scoping of Promising Interventions to Implement at the Community or State Level. Washington, DC: The National Academies Press. doi: 10.17226/27239.
×
Page 36
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Complementary feeding refers to the introduction of foods other than human milk or formula to an infants diet. In response to a request from the Centers for Disease Control and Prevention, the National Academies Health and Medicine Division convened the Committee on Complementary Feeding Interventions for Infants and Young Children under Age 2 to conduct a consensus study scoping review of peer-reviewed literature and other publicly available information on interventions addressing complementary feeding of infants and young children. The interventions studied took place in the U.S. and other high-income country health care systems; early care and education settings; university cooperative extension programs; the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC); home visiting programs; and other settings. This consensus study report summarizes evidence and provides information on interventions that could be scaled up or implemented at a community or state level.

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