"For your interpretation to be accurate, you’d need to also show that the other popular medicine doesn’t work for diabetes type 2 treatment." This is not true.

"For your interpretation to be accurate, you’d need to also show that the other popular medicine doesn’t work for diabetes type 2 treatment." This is not true. It's possible that there are multiple effects of type 2 diabetes, with multiple drugs that treat the main factor (sugar levels), but with a subset of the drugs affecting other factors (hormones, cellular activities, something else) that influence dementia.