Spanish school books: can we believe what they say about health?

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Most school textbooks contain messages about health. But there's no known evidence for about a quarter of the messages. At least, that's the position in Granada, Spain, according to a report in BMC Public Health.

The researchers, who come from health institutions in Granada, analysed the textbooks used in the local schools. They found that 129 out of the 237 books, so 54% of them, did contain at least one health message. (There were health messages in textbooks in mathematics and in Spanish language and literature, for instance, as well as in books on biology or the environment where one might expect to see them.)

A sample of 80 of the books containing health messages was used for further investigation. The researchers listed all the health messages and checked them against standard information sources on evidence in health, using the Trip Database to search for these sources.

Overall, they found that 24.6% of the health messages that they analysed had no supporting evidence at all. Indeed a couple of them went in entirely the opposite direction from established evidence.

Of course, one mustn't read too much into this. Perhaps there really is evidence for some of these health messages, but the Granada researchers just failed to find it in their search (though they did look pretty hard). And perhaps this position is unique to Spain, or even to Granada, though I have to say that my personal prior probability would be quite high that a similar state of affairs exists in schools in other coutnries such as the UK. (But I have no evidence for that!)

(Actually I must be more pessimistic than is good for me, because it cheered me up to see that as many as three quarters of the health messages did have supporting evidence!)