[cutting/comment] Alcohol and cancer: What does a ‘500% increase’ in risk really mean? | Health News Review

Last night, NBC Nightly News ran a story about the cancer risks related to alcohol consumption. But instead of communicating those risks in a way that would educate and inform, NBC’s coverage was an example of misinformation and fear-mongering. … Viewers who think an MD byline ensures the ultimate in accurate and balanced TV reporting should think again.

Source: www.healthnewsreview.org/2017/11/alcohol-cancer-500-increase-risk-really-mean/



Comment:  Agreed: Journalists should try to include absolute risk in their stories. So we should not just say, for instance, that the odds of something happening has doubled, but from what. Has it gone from, say, one in a million to two in a million or from one in three to two in three? That said, indications of absolute risk are often not readily available. Journalists cannot be expected to do the advanced statistical conjuring needed to turn relative risk into absolute risk, whether or not they are medical doctors. Medical doctors too are also rarely advanced statisticians, nor can they be expected to be familiar with all the epidemiological nuances they would need to perform such a manipulation. I would also shy away from interfering with data in this way, knowing as a rusty mathematician that it is unlikely to be straightforward. In this particular case, as in many others, the statement from the American Society of Clinical Oncology only contains figures for relative risk (see table), although this accompanying release says 5-6% of new cancers and cancer deaths are “directly attributable to alcohol”. The society told Alcohol Companion that its figures imply around 3,326 deaths from alcohol related cancer for every 100,000 cancer deaths, meaning alcohol is involved in around 1 in 30 cancer deaths. Incidentally, heavy drinking appears to multiply the risk of head and neck cancer by five, which is a 400% increase in risk, rather than the 500% in the graphic and headline. It would be interesting to know if the society has more detailed absolute risk figures for each type of cancer. Typically news stories will need to be reported well before any request for additional figures is answered. ■