That’s a hard question to answer because no one really knows. There are, however, differences in the approach to child rearing that may have an impact. In my young days, that were post WWII, children were given everything to eat and there was no thought of allergies. The closest my body came to one was that of dust from which sinus would result. No one in my family or anyone we knew, however, ever mentioned allergies.
Babies were reared with a taste of everything, even when they spat it out. Eggs were high on the menu as were nuts, fruits, vegetables of all types, and, of course, meat. My children were given exactly the same treatment. My babies received cows milk when they were weaned and nothing was held back by way of food.
My daughter, by way of contrast, read books to determine what her children should eat. They were denied eggs and lots of other foods. The result, which might have come from this practice, is that one of them is highly allergic to certain fo