Coffee and breast cancer

As of the 23rd May 2022 this website is archived and will receive no further updates. 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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The media today are full of reports that women who drink lots of coffee might reduce their risk of developing one type of breast cancer. For instance, the BBC reported on it here, and the Daily Mail here. But is the evidence really there?

As usual, things are really a bit more complicated than the press articles might have implied. I might have blogged about that, but I'm saved the trouble, because there's an excellent blog item about it by Ed Yong on the Cancer Research UK website.

If you're concerned about breast cancer risk, or just generally interested in risk and uncertainty, you should go and read it. It's full of lots of's favourite topics - for instance, the need to look at the wider research picture, the fact that an association between two things doesn't necessarily mean that one is causing the other, and the fact that the press release about a study doesn't necessarily communicate the right conclusions.