A report in a medical journal notes that the risk of developing Alzheimer's disease among subjects who (voluntarily) regularly took the anti-inflammatory drug ibuprofen (the active ingredient in Advil) was about half the risk among those who did not. Is this good evidence that ibuprofen is effective in preventing Alzheimer's disease?
A) Yes, because the study was a randomized, comparative experiment.
B) No, because the effect of ibuprofen is confounded with the placebo effect.
C) Yes, because the results were published in a reputable professional journal.
D) No, because this is an observational study. A clinical trial would be needed to confirm (or not confirm) the observed effect.
E) Yes, because a 50% reduction can't happen just by chance.

Question

Quizplus · Accepted Answer

The study described is an observational study, meaning that the subjects were not randomly assigned to take ibuprofen or not. There may be other factors (confounding variables) that could have influenced the results, such as overall health or other lifestyle factors. Therefore, a clinical trial would be needed to confirm whether ibuprofen is truly effective in preventing Alzheimer's disease.

A Report in a Medical Journal Notes That the Risk