We're nearly all at increased risk!!

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understandinguncertainty.org was produced by the Winton programme for the public understanding of risk based in the Statistical Laboratory in the University of Cambridge. The aim was to help improve the way that uncertainty and risk are discussed in society, and show how probability and statistics can be both useful and entertaining.

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Submitted by horace on Fri, 20/02/2009 - 9:06am

Monday's headline in the Daily Telegraph: Nine in 10 people carry gene which increases chance of high blood pressure sounds shocking. Next thing they will be telling us that we are all going to die.

The story is about a recent Nature Genetics paper. They looked at a particular spot on the genome, where one of three gene variants could be present: the two rarer of these, present in 10% of the population, reduced the odds on hypertension (high blood pressure) by 15%. An interesting scientific result, but nowhere in the original paper is there any mention of all these people at increased risk.

However, if we look at the 90% of people that have the common gene variant, then with some stretch of the imagination we can certainly consider them as having a gene that increases the risk of hypertension by 18%! [The 15% decrease takes us from a baseline of 1 to 0.85, but an increase from 0.85 to 1 is an 18% increase]. This is a masterful piece of re-framing of the evidence: not exactly wrong, but definitely changing the story. Just like a change from 98% to 96% survival seems a lot more innocuous than a doubling of mortality from 2% to 4%.

Some of the coverage of the story follows the line of the original paper, so who is responsible for the re-framing? It seems to have originated in the AFP news agency, who perhaps should be congratulated on their numerical skills.

See the Plus blog for more on this story.

David S

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Comments

Anonymous (not verified)

Mon, 01/06/2009 - 7:41am

I've always thought that a problem with media "scientists have discovered a genetic/dietary/whatever factor that increases risk of thingummy" stories is the doom-mongering way they make it sound that the overall population risk of thingummy has increased. Which of course it hasn't - all such a discovery means is that the risk can be re-distributed by exposure/non-exposure to the factor.

But I never thought journalists would be so blatant as to take a "scientists have discovered a factor that decreases risk" story and turn it on its head.