People are now looking to target older studies for possible drug risks. The problem is that these analyses are retrospective, and thus should be taken with a grain of salt. Since when did the double-blind, randomized-controlled prospective study stop being the gold standard?

As he examined data on a computer one day last fall, drug-safety reviewer Ralph Edwards saw something that concerned him: Of 172 people in his database who developed Lou Gehrig’s disease or something similar while taking prescription medicines, 40 had been on statins, the huge-selling cholesterol drugs.

Dr. Edwards, director of the World Health Organization’s drug-monitoring center, has amassed about four million reports of medical problems experienced by people taking prescription drugs. His job is to sift through these so-called adverse events, looking for “signals” of potential side effects.