Study: Breast Feeding No Better Than Bottle Feeding For Kids’ Health

[jeff47]

83. The idea was to look for things that are frequent secondary effects

For example, that hearing loss should have affected "scores predicting academic achievement in vocabulary", which would affect "scores predicting (...) scholastic competence." Hearing loss slows language acquisition.

That's why they chose such broad categories. Instead of trying to run down every single possible effect, they picked things that can be affected by many things. If they had found a higher or lower rate of "achievement in vocabulary", then a follow-up study would try to figure out why.

As for your specific example, we could also use my sister as an example if you'd like. She was breast fed. Damn near every single cold during her childhood became an ear infection. So that would kind of indicate breast feeding wouldn't have altered your sister's outcome. Though we'd need data instead of anecdotes to really sort that out.