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Draft Research Plan

Early Introduction of Allergens to Prevent Food Allergies in Infants: Counseling

May 09, 2024

Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.

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Figure 1 is the analytic framework that depicts the four Key Questions to be addressed in the systematic review. The figure illustrates how counseling interventions for the early introduction of allergens in unselected or increased-risk infants increase rates of early allergen intake and/or reduce food allergy and food allergy-related morbidity and mortality (Key Question 1), along with any related harms (Key Question 2). The figure also shows whether the early introduction of allergenic foods in unselected or increased-risk infants reduces food allergy and/or food allergy-related morbidity and mortality (Key Question 3), along with any related harms (Key Question 4).

 

1. Does counseling for early introduction of allergens in unselected or increased-risk infants increase rates of early allergen intake and/or reduce food allergy and food allergy–related morbidity and mortality?
   1a. How is “increased risk” defined in the included trials?
2. Does counseling for early introduction of allergens in unselected or increased-risk infants result in harms?
3. Does early introduction of allergenic foods in unselected or increased-risk infants reduce food allergy and/or food allergy–related morbidity and mortality?
4. Does early introduction of allergenic foods in unselected or increased-risk infants result in harms?

Contextual Questions will not be systematically reviewed and are not shown in the Analytic Framework.

  1. What are facilitators and barriers to equitable and accessible implementation of early food allergen introduction, including the use of counseling and pre-exposure testing?

To the extent possible, we plan to describe the population, risk assessment, and intervention characteristics of the included studies. Data on population characteristics will help us to explore the degree to which the findings are representative of different populations of persons at risk for food allergy. These groups include, but are not limited to, categorizations by various social determinants of health, such as education level, socioeconomic status, age, gender, and racial, ethnic, and cultural identity. We will endeavor to determine if the early introduction of food allergen interventions developed and customized for specific populations are effective in those populations.

The Proposed Research Approach identifies the study characteristics and criteria that the Evidence-based Practice Center will use to search for publications and to determine whether identified studies should be included or excluded from the Evidence Review. Criteria are overarching as well as specific to each of the Key Questions.

Category Included Excluded
Aim KQs 1, 2: Effect of counseling to encourage early introduction of allergenic complementary foods to prevent IgE-mediated food allergies

KQs 3, 4: Examining the biological impact of early introduction of allergenic complementary foods to prevent IgE-mediated food allergies

 Prevention of non-IgE–mediated conditions (e.g., celiac disease, contact dermatitis, protein-induced enterocolitis)
Population Unselected and increased-risk, full-term infants ages 0 to 12 months Infants with known food allergy to specific allergen being introduced; preterm infants
Interventions KQs 1, 2: Counseling for early oral allergen* introduction in infants, as defined by study

KQs 3, 4: Early oral allergen* introduction in infants, as defined by study

 Alternative-milk formula feeding; differences in exclusivity for duration of breastfeeding; maternal dietary interventions and allergen restrictions; and multifactorial interventions in which the allergen introduction intervention effectiveness cannot be isolated
Comparators KQs 1, 2: Usual care or later introduction, as defined by study

KQs 3, 4: Usual care, later introduction, or placebo

  
Outcomes KQs 1, 3:
  • Incidence of food allergies, preferably as diagnosed by oral challenge test
  • Sensitization (e.g., positive skin prick)
  • Incidence of allergic reactions, including anaphylaxis or fatal reactions, after the intervention period
  • Quality of life
  • Rates of introduction of allergenic foods (KQ1 only)

KQ2: Psychological harms (e.g., anxiety)

KQ4:

  • Withdrawal due to adverse events, as reported in the studies
  • Serious adverse events attributable to the intervention, including anaphylaxis or fatal reactions
  • Allergic reactions in household members with known food allergy
  • Changes to growth or metabolic parameters
  
Followup Any  
Study Designs RCTs NRSIs
Setting Any clinical setting  
Countries Countries categorized as “Very High” on the 2021–2022 Human Development Index (as defined by the United Nations Development Programme) Countries that are not categorized as “Very High” on the 2021–2022 Human Development Index
Language English only Non-English language publications
Quality Fair or good quality, according to design-specific criteria Poor quality, according to design-specific criteria

* Nine major food allergens in any form or combination: milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans, and sesame.

Abbreviations: KQ=Key Question; IgE=immunoglobulin E; NRSI=nonrandomized study of intervention; RCT=randomized, controlled trial.