This is ridiculous (from The Guardian):

Processed meats rank alongside smoking as cancer causes – WHO

UN health body says bacon, sausages and ham among most carcinogenic substances along with cigarettes, alcohol, asbestos and arsenic

Bacon, ham and sausages rank alongside cigarettes as a major cause of cancer, the World Health Organisation has said, placing cured and processed meats in the same category as asbestos, alcohol, arsenic and tobacco.

The report from the WHO’s International Agency for Research on Cancer said there was enough evidence to rank processed meats as group 1 carcinogens because of a causal link with bowel cancer.

It places red meat in group 2A, as “probably carcinogenic to humans”. Eating red meat is also linked to pancreatic and prostate cancer, the IARC says.

The IARC’s experts concluded that each 50-gram (1.8-ounce) portion of processed meat eaten daily increased the risk of colorectal cancer by 18%.

Really – they found “a causal link with bowel cancer”?  I don’t think so.  What they found was that people who eat more processed meat have a higher incidence of cancer.  It’s easy to play around with the data and identify some correlation between two items, but if you want to go on to establish a causal link you need to do a much better study that eliminates most of the other variables. 

And “Bacon, ham and sausages rank alongside cigarettes as a major cause of cancer”.  Well, not really.  The Q&A (issued with the press release) says that:

this does NOT mean that they are all equally dangerous.  The IARC classifications describe the strength of the scientific evidence about an agent being a cause of cancer, rather than assessing the level of risk.

I think it’s that weasel word “alongside” (used by The Guardian in their headline as well as the body of the article), with its implication that they are somehow equivalent.  Which they aren’t. 

We know beyond all reasonable doubt that smoking causes cancer, we certainly don’t know that about sausages, ham and bacon.  Plus, all they are saying is that your risk of these cancers might go up from 5% to 6%.

Other journalists have added their own speculation.  There was a cover story in Time magazine that included the suggestion that it could be the nitrates / nitrites (probably not, as the body produces nitrites) or the process of cooking (grilling, frying, BBQ) – but I’m sure that theory was debunked.   

I can think of two simple explanations.  People who eat a lot of sausages and bacon might have a generally unhealthy lifestyle and could well be overweight, or could it just be the quality of the meat that is used in cheap sausages and ham?  But neither of those would really be news.