乳児期早期からの離乳食

この実験は大切なことを示唆しています。

生後6ヶ月から微量の卵パウダーを離乳食に混ぜて与え続けると、除去していた子に比べて、1歳の時点での卵アレルギーが1/5に減ったという事実です。

同じようなことは2000年より以前から知られていまいしたが、2000年以降からたくさんの論文が出てくるようになって、2007〜2008年頃までにはアレルギー学会では早くから食べた方が安全であることは常識になっていました。

しかしすでにアレルギーを発症してしまった子に対して、どうやって安全性を担保するかが課題でした。

この論文の大切な点は、「早くから食べた方が良い」という事実ではありません。

わずかに0.05g/日を3ヶ月間、その後、0.25g/日を3ヶ月間続けるという負荷を毎日続けることで、1歳の時点で卵半分(32g)が食べらる子がかなり増えたということです。

イスラエル在住のユダヤ人は生後6ヶ月から離乳食にピーナッツを混ぜるという文化があるそうです。

一方で、イギリス在住のユダヤ人はイギリス式に2歳までピーナッツを避けています。

統計的には、イギリス在住のユダヤ人の方がピーナッツアレルギーが多いのです。

他のタンパク抗原でも同様の結果を示す論文が多数出ています。

生後5ヶ月には離乳食を始め、6ヶ月までには多くのタンパク抗原を微量から開始してください。

早期からの微量のタンパクを摂り続けることで、アレルギーを予防できます。

もう一つ、スキンケアも大切です。

食物アレルゲンの感作場所は皮膚です。

ステロイドの力を借りてでも、皮膚の炎症を抑えた方が食物アレルギーを予防できるのです。

Two-step egg introduction for prevention of egg allergy in high-risk infants with eczema (PETIT): a randomised, double-blind, placebo-controlled trial

Osamu Natsume, MD*, Shigenori Kabashima, MD*, Junko Nakazato, MD, Kiwako Yamamoto-Hanada, MD, Masami Narita, MD, Mai Kondo, MD, Mayako Saito, MD, Ai Kishino, MD, Tetsuya Takimoto, MD, Eisuke Inoue, PhD, Julian Tang, PhD, ProfHiroshi Kido, MD, Prof Gary W K Wong, MD, Kenji Matsumoto, MD, Hirohisa Saito, MD, Dr Yukihiro Ohya, MDPress enter key for correspondence informationPress enter key to Email the author for thePETIT Study Team†

*Contributed equally

†A complete list of PETIT Study Team members is provided in the appendix

Published: 08 December 2016

DOI: http://dx.doi.org/10.1016/S0140-6736(16)31418-0

Summary

Background

Evidence is accumulating that early consumption is more beneficial than is delayed introduction as a strategy for primary prevention of food allergy. However, allergic reactions caused by early introduction of such solid foods have been a problematic issue. We investigated whether or not early stepwise introduction of eggs to infants with eczema combined with optimal eczema treatment would prevent egg allergy at 1 year of age.

Methods

In this randomised, double-blind, placebo-controlled trial, we enrolled infants 4–5 months of age with eczema from two centres in Japan. Exclusion criteria were being born before 37 weeks of gestational age, experience of ingestion of hen's eggs or egg products, history of immediate allergic reaction to hen's eggs, history of non-immediate allergic reaction to a particular type of food, and complications of any severe disease. Infants were randomly assigned (block size of four; stratified by institution and sex) to early introduction of egg or placebo (1:1). Participants in the egg group consumed orally 50 mg of heated egg powder per day from 6 months to 9 months of age and 250 mg per day thereafter until 12 months of age. We aggressively treated participants' eczema at entry and maintained control without exacerbations throughout the intervention period. Participants and physicians were masked to assignment, and allocation was concealed. The primary outcome was the proportion of participants with hen's egg allergy confirmed by open oral food challenges at 12 months of age, assessed blindly by standardised methods, in all randomly allocated participants who received the intervention. This trial is registered with the University Hospital Medical Information Network Clinical Trials Registry, number UMIN000008673.

Findings

Between Sept 18, 2012, and Feb 13, 2015, we randomly allocated 147 participants (73 [50%] to the egg group and 74 [50%] to the placebo group). This trial was terminated on the basis of the results of the scheduled interim analysis of 100 participants, which showed a significant difference between the two groups (four [9%] of 47 participants had an egg allergy in the egg group vs 18 [38%] of 47 in the placebo group; risk ratio 0·222 [95% CI 0·081–0·607]; p=0·0012). In the primary analysis population, five (8%) of 60 participants had an egg allergy in the egg group compared with 23 (38%) of 61 in the placebo group (risk ratio 0·221 [0·090–0·543]; p=0·0001). The only difference in adverse events between groups was admissions to hospital (six [10%] of 60 in the egg group vs none in the placebo group; p=0·022). 19 acute events occurred in nine (15%) participants in the egg group versus 14 events in 11 (18%) participants in the placebo group after intake of the trial powder.

Interpretation

Introduction of heated egg in a stepwise manner along with aggressive eczema treatment is a safe and efficacious way to prevent hen's egg allergy in high-risk infants. In this study, we developed a practical approach to overcome the second wave of the allergic epidemic caused by food allergy.

Funding

Ministry of Health, Labour and Welfare, and National Centre for Child Health and Development, Japan.