Does anyone understand the reasoning behind this study?
http://health.yahoo.net/news/s/ap/us_med_stroke_younger_victims Maybe there is a better link to the raw data somewhere. It says that stroke is rising in the younger age groups but dropping in the older groups. I am not sure I understand why it would be dropping in the older population. They say it is because the older are maybe being better treated for high blood pressure, but later they said they controlled for blood pressure as a variable. Did they control for blood pressure but not for treatment of blood pressure? They also insinuate salt causes stroke, but later mentioned that most salt intake comes from processed foods. Did they control for processed food intake? Perhaps not.
asked byEva (20807)
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on February 10, 2011
at 07:16 AM
I am not sure I understand why it would be dropping in the older population. They say it is because...
There is no indication in the article that the researchers tried to explain why these facts occured. It appears to be a purely empirical study, one that reports the facts but doesn't try to find causes for them. In general, science has two stages. First it reports what, then it asks why. This study seems to belong to the first stage.
In a different article about this same study, the reporter says, "For George [one of the researchers], it is unclear if modern imaging techniques or better understanding of stroke symptoms are to blame for the apparent rise in numbers. She says it???s impossible to tell."
In other words, the researchers don't even know if the trend in younger people that they measured is real. The trend may just be the result of better diagnosis.
In a third article about this study, the same researcher, Dr. Mary George, is quoted as saying:
"Whether it [the rise in stroke among young people] is associated with increasing trends in traditional risk factors for stroke is unknown at this time," but "we clearly need to study" this possibility.
In other words, she is saying that the causes of the trend are unknown, but the next step, following this study, is to conduct more studies that look for the causes.
The article quotes some people guessing about why these facts are happening, but those guesses aren't part of the study.
For example, the article quotes Dr. Ralph Sacco speculating that stroke is increasing in young people because obesity is rising in that age group. But the study doesn't attempt to establish whether that's true.
The article also says that Dr. Jeffrey Saver told the reporter that more strokes are occuring in young people as a result of high blood pressure and clogged arteries, but there is no indication that Dr. Saver has anything to do with the study. He seems to be an audience member that the reporter interviewed. The reporter should have made this clear, but didn't.
...but later they said they controlled for blood pressure as a variable.
That's from a different study. The article you linked talks about two separate studies. The article has a sentence that begins, "Also at the conference..." It then goes on to describe a study about soda. The blood pressure comment describes the second study.