A systematic review of early food introduction found early introduction of peanuts to decrease the risk of peanut allergy by RR 0.60 (0.46-0.77) «Scarpone R, Kimkool P, Ierodiakonou D, ym. Timing ...»1. In the Finnish population, the risk of egg allergy is about 1-2%, which translates into an absolute reduction of 4-8 cases per 1000 infants. The early introduction increased the study withdrawal, RR 1.58 (1.12-2.22, event rates in early introduction 1605/3811 and in later introduction 586/3631). Relative risks for study withdrawal were lower in placebo-controlled trials, suggesting good tolerability, but difficulties in the implementation/acceptability of the intervention.
The evidence is indirect as the comparator groups introduced egg consumption at 8 months (only one small study on high-risk population compared introduction at 3-4 months versus 12 weeks later).
| Reference | Study type | Population | Intervention and comparison | Outcomes | Risk of bias |
|---|---|---|---|---|---|
| SR=systematic review; MA=meta-analysis | |||||
| «Scarpone R, Kimkool P, Ierodiakonou D, ym. Timing ...»1 | SR and MA | Infants 3-6 months old. Both low and high-risk populations. | Egg introduction between 3 and 6 months of age vs placebo or no intervention until 6 months or later | Egg allergy: double-blind, placebo-controlled food challenge; open food challenge; medical diagnosis at 12 months. | moderate |
| Reference | Comments |
|---|---|
| «Scarpone R, Kimkool P, Ierodiakonou D, ym. Timing ...»1 | Only 2 of 9 studies were placebo controlled, although this may not be so important as the outcome is not subjective. 5 trials in high-risk populations and 4 trials in low/standard risk populations. In two trials egg was introduced at 6 months or later. In other trials at 8 months or later. One big trial compared early food introduction to exclusive breastfeeding to at least until 6 months of age. |
| Reference | Number of studies and number of patients (I/C) | Follow-up time | Absolute number of events I | Absolute number of events C | Relative risk (95% CI) |
|---|---|---|---|---|---|
| I= intervention; C=comparison; CI=confidence interval | |||||
| «Scarpone R, Kimkool P, Ierodiakonou D, ym. Timing ...»1 | 9 (2395/2416) | 12 months | 86/2395 | 146/2416 | 0.60 (0.46-0.77) |
| Level of evidence: moderate The quality of evidence was downgraded by one level due to risk of bias and indirectness combined. |
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