11 Feb 2011 0:34
Apparently some researchers reported that some number went up recently, and the number that went up had something to do with stroke and something to do with 15-44 year-olds.
Sounds like a good excuse for a rousing chorus or two of Fire in the Theater! Obesity! Diet Soda! You’re Gonna Die!, no?
The number reported to have gone up recently is not the total number of strokes among 15-44 year-olds, nor is it the rate (per 10,000 people, for example) of strokes among people that age.
The number that went up recently is the rate of strokes in 15-44 year-olds as a fraction of all hospitalizations for that age group. Not an easy quantity to conceptualize. But when a quantity is hard to conceptualize, you aren’t automatically allowed to grab a “you may pretend it’s something else.” pass and lie with impunity. (Do these same journalists give up and write “Boxer” if they can’t spell “Feinstein”?)
Maybe the stroke rate among 15-44 year-olds is not going up.
It could be that hospitalizations of 15-44 year-olds for reasons other than stroke are going down. Maybe hospitals are more and more likely to list multiple reasons for hospitalization than in the past. Maybe many former headaches are now deemed strokes (thanks to the proliferation of imaging tests). Either of these trends would make the numerical rate of stroke diagnoses per 10,000 hospitalizations go up without reflecting an increase in stroke.
Maybe a lot of things. Maybe the rate of stroke is going up among young people. Which might be scary. Or not. It’s possible more and more diagnoses of stroke are insignificant — no worse than a bad headache. Just because “stroke” sounds scary doesn’t mean there can’t be innocuous kinds of stroke.
Unfortunately we don’t know from today’s irresponsible scramble to turn numbers into fear.