Don’t be fooled by eye-catching statistics
Let’s say the risk of having a heart attack in your fifties is 50 per cent higher if you have a high cholesterol. That sounds pretty bad. Let’s say the extra risk of having a heart attack if you have a high cholesterol is only 2 per cent. That sounds OK to me. But they’re the same (hypothetical figures). Let’s try this. Out of a hundred men in their fifties with normal cholesterol, four will be expected to have a heart attack; whereas out of a hundred men with high cholesterol, six will be expected to have a heart attack. That’s two extra heart attacks per hundred.
Goldacre B. Bad Science. London: Fourth Estate 2008, pp239-40.