Does processed meat cause as much cancer as smoking? WHO knows

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Report by NewsroomPlus.com

If you were left feeling confused by the media coverage of a recent report from the International Agency for Research on Cancer (IARC), don’t fret, you’re in good company.  

A two-page press release, and Lancet article, from the IARC – an agency of the World Health Organisation – has caused a stir internationally, with everyone from the usually reliable Guardian to underlings like the NZ Herald getting caught up in some sloppy journalism.

The report, based on the accumulated research of over 800 studies, announced that processed meat is deemed ‘carcinogenic to humans’, and now included in a list of known carcinogens that cause cancer. The inclusion of processed meat in this list, which also includes tobacco, asbestos and alcohol, has prompted many to wrongly assume that it is as bad for you as other carcinogens.

These overcooked headlines say it all:

“Avoid bacon and sausages… they’re as bad as cigarettes”

“Processed meats rank alongside smoking as cancer causes – WHO”

“Bacon’s as bad as asbestos? WHO thinks so”

To further complicate matters, the same report deemed red meat to “probably cause cancer”. A statement that was disastrously misunderstood and subsequently reported, by some outlets, with tabloid-esque pageantry.

Cue frantic efforts from the meat industry to restore calm, including manufactured polls like this from Beef Magazine:

A recent beefmagazine.com poll asked BEEF readers, “Do you think WHO has an anti-beef agenda?” With 87 votes so far, 79% of voters said, “Yes, the recently released cancer report saying beef is a carcinogen is bad science.” Another 14% said, “No, the report is accurate.” The remaining 7% aren’t sure.

Some local TV news shows managed to mangle the story even moreso than their peers in print and online media. Radio NZ’s Mediawatch dissected the mess on Sunday, with TV shows 3 NewsSeven Sharp and Story the main perpetrators of some seriously sloppy journalism.

This from 3 News:

“There’s a warning for those who love a classic Kiwi fry-up. According to the World Health Organisation (WHO), processed meat like bacon and sausages are as big a cancer threat as cigarettes.”

So was the confusion a failure of the media or the IARC?

The Atlantic went straight for the throat of the IARC and its methods, asking, “Why is the world health organization so bad at communicating cancer risk?” It is, to some degree, a fair assessment. The method of the IARC’s findings is certainly confusing at first glance.

And the Irish Times posted an excellent article, both defending our right to collective confusion – when faced with oblique scientific reports – and suggesting that the media’s pursuit of clickable headlines is partly to blame:

Misuse of information based on statistics is not uncommon. “The headlines are designed to pull out scare-mongering facts,” says Dr Caroline Brophy of the department of maths and statistics at Maynooth University.

The agency’s study was an observational one and showed a tenuous connection between red meat and cancer, she said. But these were correlations rather than proof of causation.

A large factor in how the story was so inaccurately reported concerned this line from IARC’s summary and press release:

“The experts concluded that each 50 gram portion of processed meat eaten daily increases the risk of colorectal cancer by 18%.”

This triggered some significant fireworks, and a fair amount of public outcry by meat-loving people everywhere. The World Health Organisation received enough backlash to release a statement clarifying their position and involvement:

IARC’s review confirms the recommendation in WHO’s 2002 “Diet, nutrition and the prevention of chronic diseases report, which advised people to moderate consumption of preserved meat to reduce the risk of cancer. The latest IARC review does not ask people to stop eating processed meats but indicates that reducing consumption of these products can reduce the risk of colorectal cancer.

It could be argued that the problem began, not with IARC’s press release, but with the headline-hunting of the media outlets who first covered it. It’s a common failure that we’re all familiar with – a failure to clarify and verify the facts, albeit under the imposed pressure of embargo-driven rushes.

In Bill Kovach and Tom Rosentiel’s definitive guide, The Elements of Journalism, this kind of reporting falls under a basic principle of journalism – the discipline of verification.

To quote Kovach and Rosentiel:

In the end, the discipline of verification is what separates journalism from entertainment, propaganda, fiction, or art. Entertainment – or its cousin “infotainment” – focuses on what is most diverting… Journalism alone is focused on the process employed to get what happened down right.

So what did the press release say that the media found so confusing? The report clearly states the agency’s findings, in regards to both red and processed meat:

Red meat

After thoroughly reviewing the accumulated scientific literature, a Working Group of 22 experts from 10 countries convened by the IARC Monographs Programme classified the consumption of red meat as probably carcinogenic to humans (Group 2A), based on limited evidence that the consumption of red meat causes cancer in humans and strong mechanistic evidence supporting a carcinogenic effect.

Processed meat

Processed meat was classified as carcinogenic to humans (Group 1), based on sufficient evidence in humans that the consumption of processed meat causes colorectal cancer.

The use of groups to catagorise carcinogens is somewhat confusing, especially when you consider that group 1 – ‘carcinogenic to humans’ – includes items with a wide variety of risk (Cigarettes are not equal in risk to alcohol, nor is asbestos to processed meat etc). But when you get right down to what was reported and why, the blame for the confusion can surely be laid upon the media and some sloppy journalism.

So what does the report actually tell us?

Arguably, the best coverage came from the Cancer Research UK’s blog, who were one of the few to unpack the science in a way that made sense to laymen. They produced a useful graphic, shown below, which explains the use of catagories, as well as clarifying the point that tripped the media up in the first place – that the ‘catagories represent how likely something is to cause cancer in humans, not how many cancers it causes.’

151026-IARC-Meat-rating-TWITTER

So to give a summary of what IARC’s report means, once properly broken down, this from the same article:

The results showed that those who ate the most processed meat had around a 17 per cent higher risk of developing bowel cancer, compared to those who ate the least.

‘17 per cent’ sounds like a fairly big number – but this is a ‘relative’ risk, so let’s put it into perspective, and convert it to absolute numbers. Remember these are all ball-park figures – everyone’s risk will be different as there are many different factors at play.

We know that, out of every 1000 people in the UK, about 61 will develop bowel cancer at some point in their lives. Those who eat the lowest amount of processed meat are likely to have a lower lifetime risk than the rest of the population (about 56 cases per 1000 low meat-eaters).

If this is correct, the WCRF’s analysis suggests that, among 1000 people who eat the most processed meat, you’d expect 66 to develop bowel cancer at some point in their lives – 10 more than the group who eat the least processed meat.

And to provide some scope on the matter, they compare the difference of risk between tobacco and processed meat, by use of another handy graphic (Which the Guardian picked up and used in some great follow up articles, redeeming their earlier sloppiness).

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Interestingly, the Science Media Exchange (Scimex), released an informative reaction on the same day of IARC’s official press release, offering expert context and scope for media use. Unfortunately, no one picked it up and ran with it. If they had, the headlines may have read very differently.

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Selwyn Manning, BCS (Hons.) MCS (Hons.) is an investigative political journalist with 23 years media experience. He specializes in reportage and analysis of socioeconomics, politics, foreign affairs, and security/intelligence issues. Selwyn has extensive experience as a commentator and has provided live political analysis to a wide range of television and radio organizations broadcasting in New Zealand, Australia and globally including the BBC (Five Live, London) and BBC (World Service). He is currently a correspondent to Australia's FiveAA radio, and is a regular live-on-air panelist on Radio New Zealand's The Panel with broadcaster Jim Mora.

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