Original Medical Opinion of the Day

Depending on how you look at it, that's today or April 3rd.

Barry Marshall and Robin Warren won the 2005 Nobel prize in medicine because, in the words of the Nobel organization,

they made an irrefutable case that the bacterium Helicobacter pylori is causing disease. By culturing the bacteria they made them amenable to scientific study.

In 1982, when this bacterium was discovered by Marshall and Warren, stress and lifestyle were considered the major causes of peptic ulcer disease. It is now firmly established that Helicobacter pylori causes more than 90% of duodenal ulcers and up to 80% of gastric ulcers. The link between Helicobacter pylori infection and subsequent gastritis and peptic ulcer disease has been established through studies of human volunteers, antibiotic treatment studies and epidemiological studies.

Seth Roberts comments:

It turned out that Helicobacter pylori was present in half the stomachs in the world — only a tiny fraction of which developed ulcers. So much for causation. Marshall and Warren did not consider that lifestyle factors might cause immune efficiency to go down, leading to increased growth of the bacterium. In a famous example of self-experimentation, Marshall ingested a giant amount of the supposedly dangerous bacterium — but, uh-oh, didn’t get an ulcer.

Does he have a point? Two? Three?