alt Hacker NewsSo you can reduce your dementia incidence risk from Q1 -> Q5 by a whopping 0.08%-points. But in media you surely will read about a 40% reduction.
*edited: %-points instead of %
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Sure, because both are true (although that 0.08% is only over 8 years of known omega 3 consumption - as timescales increase the absolute risk moves towards the relative risk).
That 0.08% reduction would mean approximately 28,000 fewer EOD cases - not to be sniffed at!
The 40% (66%?) is the number that matters. Same way you wearing a helmet reduces your changes of brain damage in a motorcycle accident by 90%, yet you’re not on a motorcycle most of the time.
This is talking about early onset, which is a particularly terrifying outcome. And yes, 1 in 1000 for a horrible outcome sounds much better than 2 in 1000, doesn't it?
And to be clear, many things that people worry about is less likely than that. Homicides (over an 8 year period about about 0.04 per 1000 people), terrorism (vanishingly small), and on and on.
None of this means that people should stock up on omega-3s, and as likely the study is actually finding a correlation with something else (e.g. wealthier people enjoy more fish rich diets and are less exposed to toxins, or something else), but halving something terrifying that isn't that uncommon is legitimately newsworthy.
The reduction in risk is 0.08 percentage points, not 0.08 percent. The "%" symbol always means "percent", not "percentage points". The 0.08 percentage point reduction is a 40% reduction.
EDIT: don't assume the causality