[brewdad]

From the study[1]: "Several years ago, we found that the risk of the development of peanut allergy was 10 times as high among Jewish children in the United Kingdom as it was in Israeli children of similar ancestry. This observation correlated with a striking difference in the time at which peanuts are introduced in the diet in these countries: in the United Kingdom infants typically do not consume peanut-based foods in the first year of life, whereas in Israel, peanut-based foods are usually introduced in the diet when infants are approximately 7 months of age"

So, the difference in real-world outcomes amongst Jewish populations in different countries inspired this study.

[1]: https://www.nejm.org/doi/10.1056/NEJMoa1414850?url_ver=Z39.8...