No sausages are not like cigarettes

Thomas Lumley blogs at Stats Chat:

There has apparently been a leak from the International Agency for Research on Cancer about their forthcoming assessment of meat. It’s just in the UK papers so far, but I expect it will spread. Here’s an example, from the Telegraph

“Bacon, ham and sausages ‘as big a cancer threat as smoking’, WHO to warn
The WHO is expected to publish a report listing processed meat as a cancer-causing substance with the highest of five possible rankings”

Presumably what they mean is that IARC is going to classify processed meat as a Group 1 carcinogen. The story is playing on a common misunderstanding of the IARC hazard grades for carcinogenicity.

As I’ve written before, the IARC hazard grades aren’t about the magnitude of the threat. A Group 1 carcinogen is an agent whose ability ability to cause or promote cancer is well established.

So the Telegraph has it entirely wrong. Hopefully the media here will not fall into this trap.

If the leak is correct, processed meats will be joining alcohol, plutonium, sunlight, tobacco, birth-control pills, and Chinese-style salted fish in Group 1. These aren’t all an equal threat, but the IARC scientists believe all of them are able to cause cancer at the right dose.