Dear Joseph,
You wrote:
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"I think it may be confusing when Readers are told, that '...IARC/WHO does not assess the size of risk. The International Agency for Cancer Research (IARC) used clearly defined guidelines to identify hazards (qualitative evaluation), i.e. whether an agent can cause cancer, but IARC does not assess level or the magnitude of risk (quantitative assessment). In other words, the IARC/WHO evaluates the evidence not risk...', which is sandwiched very deep in the article that has as its title, ‘WHO report says eating processed meat is carcinogenic: Understanding the findings’.
"For such apparently important ‘evidence’ that millions of people would take seriously coming from the guardian of our World’s Health, W.H.O., I think, may be confusing. Health messages should be clearer and unambiguous, especially when it deals with what may impact lives and wellbeing of billions of people, not to talk of the economy of nations. Practitioners and carers (in this era that informed selfcare is promoted) who are not 'experts' in qualitative and quantitative analysis may be confused.
"Wouldn’t it be useful to have such articles carry the caveat, up front in the first paragraph of the full content, so that they know that they are reading opinion, not proven fact?’"
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The article you refer to is here: https://www.hsph.harvard.edu/nutritionsource/2015/11/03/report-says-eati...
I agree. The original article starts as follows "Last week the World Health Organization (WHO)’s International Agency for Research on Cancer (IARC) announced that consumption of processed meat is “carcinogenic to humans (Group I ),” and that consumption of red meat is “probably carcinogenic to humans (Group 2A)” and only later states the "IARC does not assess level or the magnitude of risk". It would indeed have been useful to state this latter point up front, and perhaps also to state the implied recommendation, which I think is that the magnitude of risk needs to be assessed and communicated at country level.
The article refers to the source report but the embedded hyperlink points to a related 2015 news article in The Lancet Report (https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045%2815%290...). I needed to search for the acutal report which was published in 2018 and is available here: https://publications.iarc.fr/Book-And-Report-Series/Iarc-Monographs-On-T...
The 500-page report says (p27) "These categories refer only to the strength of the evidence that an exposure is carcinogenic and not to the extent of its carcinogenic activity (potency)"
It is the level of increased risk that every person will be asking for, and it is an understanding of the level of risk that would encourage people to eat less meat. The above article and the IARC report are consistent here, although the caveat is rather hidden by both.
I have not been able to read the full IARC report, but my interpretationo of the article is that the IARC is leaving quantitative assessment to national health systems. Such local assessment would presumably help address the fact that a few of the 800 studies did not show an association between red meat and cancer, and these differences may be related to local contextual factors. A skim through the report shows the huge complexity of how to interpret data from a large number of studies with variation in the reliability of those data.
When synthesising data it is not always possible to generate levels of risk with confidence. The bottom line is that 'Consumption of red meat is probably carcinogenic to humans (Group 2A). Consumption of processed meat is carcinogenic to humans (Group 1).' This is an objective assessment based on strong evidence, and not an opinion.
Both the report and the article indicate the difficulties of scientific communication, and possible areas where this may be improved. Both are presumably intended for a scientific rather than a lay readership. Further confusion is likely as and when journalists interpret and repackage the findings for a lay readership, and when knowledge brokers do the same for policymakers.
Moreover, the above report was published in 2018. It would be interesting to know what has been published internationally and nationally since then.
Best wishes, Neil
HIFA profile: Neil Pakenham-Walsh is coordinator of HIFA (Healthcare Information For All), a global health community that brings all stakeholders together around the shared goal of universal access to reliable healthcare information. HIFA has 20,000 members in 180 countries, interacting in four languages and representing all parts of the global evidence ecosystem. HIFA is administered by Global Healthcare Information Network, a UK-based nonprofit in official relations with the World Health Organization. Email: neil@hifa.org
