Table 1 Summary characteristics of included systematic reviews and their methodological assessments
Author (Year) | PICO/PECO | RCTs of interest (n) | NRSIs included | CompletePRISMA checklist adherence† | AMSTAR-2 | ROBIS |
|---|---|---|---|---|---|---|
Al-Saud (2018) | Population: Infants Intervention/Exposure: Early (as early as 3 months of age) introduction of egg to the diet Comparator: Exclusive breastfeeding until 6 months of age or placebo Outcome: Primary: Egg allergy diagnosed by oral food challenge; Secondary: food sensitization (presence of allergen specific IgE) confirmed by a positive allergy skin prick test or a positive ImmunoCAP, diagnosis of asthma, allergic rhinitis, eczema, anaphylaxis | 6 | No | No | Critically low quality | High RoB |
Burgess (2019) | Population: Humans from general and high-risk populations (not specified but inferred: children 0–3 years) Intervention/Exposure: Timing of introduction to complementary solid food or specific allergenic foods Comparator: Delayed or no introduction (not explicitly stated, protocol: any comp. with infants not introduced at that age) Outcome: Food sensitization determined by skin prick test or food-specific IgE, food allergy determined by food challenge or diagnosed by a physician | 8 | Yes | No | Critically low quality | High RoB |
Chmielewska (2017) | Population: Infants at population risk or increased risk of developing a wheat allergy Intervention/Exposure: Consumption of wheat- or gluten-containing products of any type (cereals, flour or any other food items containing gluten) Comparator: Placebo or no intervention/ no exposure Outcome: Incidence of wheat allergy or sensitization (increased wheat-specific IgE and/or positive skin-prick test) | 1 | Yes | No | Moderate quality | High RoB |
Dai (2021) | Population: Infants at population risk and increased risk of developing allergy Intervention/Exposure: Late consumption of any complementary foods (after 6 months of age) Comparator: Early consumption of any complementary foods (before 6 months of age) Outcome: Allergic diseases (egg allergy, peanut allergy, cow’s milk protein allergy) | 8 | No | No | Critically low quality | High RoB |
De Silva (2020) | Population: Infants (up to 1 year old), children (13 months to 17 years), and/or adults (18 + years) with or without an increased risk for developing allergic disease and with or without any sensitization or atopic manifestations Intervention/Exposure: Any intervention to prevent the development of new cases of immediate-onset food allergy (protocol: includes dietary initiatives and skin barrier initiatives) Comparator: Any independent, concurrently sampled group(s) with or without a placebo, intervention, or combination of interventions Outcome: New cases of immediate-onset food allergy, defined as a reproducible adverse response to a food protein within hours caused by an immunologic reaction | 6 | No | No | High quality | High RoB |
EFSA (2019) | Population: All population groups, males and females: generally healthy term infants, preterm infants, infants not older than 12 months of age at introduction of CFs Intervention/Exposure: Timing of introduction to CFs Comparator: Group alike in terms of the type of initial feeding (breast milk or breast-milk substitutes) and the only important difference being the time at which CF is introduced Outcome: Allergy (+ overweight and obesity, DM type 1 and 2, risk factors of CVD, coeliac disease, dental health, renal function, gastrointestinal infections, respiratory tract infections etc.) | 7 | Yes | No | Low quality | High RoB |
Ierodiakonou (2016) | Population: Infants between birth and the end of their 12th post-partum month Intervention/Exposure: Timing of introduction of allergenic food: cow’s milk, egg, fish, crustacean shellfish, tree nuts, wheat, peanuts and soybeans Comparator: Delayed or standard introduction of allergenic foods Outcome: Asthma/ wheeze, eczema, allergic rhinitis, food allergy (a reproducible hypersensitivity reaction to a food), allergic sensitization (the presence of specific IgE to an allergen), type 1 DM, celiac disease, IBD, juvenile rheumatoid arthritis, psoriasis, and vitiligo | 8 | Yes | Yes | Low quality | Low RoB |
Larson (2017) | Population: Infants Intervention/Exposure: Delaying introduction of potentially allergenic foods until after 12 months of age Comparator: Introduction of these foods prior to 12 months Outcome: Development of food allergies | 2 | Yes | No | Critically low quality | High RoB |
Obbagy (2019) | Population: Age at intervention or exposure: infants (0–12 mo), toddlers (12–24 mo); generally healthy infants fed human milk, infant formula, or both, examined through age 18 years Intervention/Exposure: Timing of introduction of CFs and beverages (CFBs), types and amounts of CFBs Different timing of introduction of CFBs, different types and amounts of CFBs Outcome: Incidence, prevalence, and/or severity of food allergy, atopic dermatitis/ eczema, asthma, and/or allergic rhinitis | 7 | Yes | No | Low quality | High RoB |
Smith (2016) | Population: Healthy breastfeeding full-term (37–42 months of gestation) infants up to the age of six months, or mothers of these infants Intervention/Exposure: Non-exclusive breastfeeding infants (artificial milk, glucose, water, foods) Comparator: Exclusive breastfeeding infants Outcome: Primary: duration of breastfeeding, incidence of infant morbidity (e.g. asthma, eczema, GI infection), infant mortality, physiological jaundice; Secondary: weight, growth, development, duration of hospital stays, confidence in breastfeeding, maximum serum bilirubin levels, phototherapy | 2 | Yes | No | Low quality | High RoB |
Waidyatillake (2018) | Population: Infants Intervention/Exposure: Timing of solid food introduction (allergenic or non-allergenic) Comparator: non-exposed group (e.g. infants not introduced to solid food by a certain age), if not available comparison depending on the age at introduction Outcome: Diagnosis of eczema | 2 | Yes | No | Critically low quality | High RoB |
Yuan (2020) | Population: Not explicitly stated (infants aged 0–12 months inferred, protocol: before 12 months of age”) Intervention/Exposure: Timing of CM or cow’s milk formula (CMF) introduction Comparator: Later or no exposure to cow’s milk or cow’s milk formula Outcome: Development of allergic diseases, including asthma, wheeze, eczema/ atopic dermatitis, allergic rhinitis/ conjunctivitis, food allergy, and cow’s milk allergy | 1 | Yes | Yes | Critically low quality | High RoB |