I’ve just been reading a Guardian article about a BMJ article about exclusive breastfeeding for six months. As a member of a university, I’m privileged to have access to many journals online, including the BMJ. I used that privilege to read the original BMJ article. I was expecting to find that I hated the Guardian article and that science journalism had, once again, taken a perfectly good paper and thrown it to the dogs. I ended up feeling a little bit sorry for the journalist.
For a start, she didn’t write the headline (a subeditor did) so I’ll give her a pass on that. Secondly, the BMJ article is a review of evidence. That means it’s absolutely chock-full of references, all summed up in one sentence. For example: “A German study found infants exclusively breast fed for six months, compared with less than four months, had less gastroenteritis.” (For the record, the German study was Rebhan B, Kohlhuber M, Schwegler U, Fromme H, Abou-Dakn, Koletzko BV. Breastfeeding duration and exclusivity associated with infants’ health and growth: data from a prospective cohort study in Bavaria, Germany. Acta Paediatr2009;98:974-80.) In one sentence, there’s no way of expressing how much less gastroenteritis they had, how many of them there were, whether the study was observational or experimental, whether there was any evidence of a continuum for babies weaned between four and six months etc. I hate it when I read this kind of summary in the press, but it’s also the bread-and-butter of an academic literature review. So, acknowledging that, we should also give Ms Bosely a pass on sentences like: “Other evidence, they say, suggests that babies not introduced to certain foods earlier than six months may have a higher incidence of food allergies.”
Journalists have to make their work interesting and relevant, and health journalists often resort to phrases like “may be harmful”, “new evidence suggests” and “scientists warn”. Ben Goldacre has plenty to say about these mysterious scientists and our unfounded faith in them to know everything, so I won’t flog that particular horse here. What’s really annoying is “may be harmful”. In this article, the phrase is: “failing to start weaning babies on to solids before six months could be harmful”. Thinking about a baby (soft, squishy beings who put everything in their mouths and are incapable of running away) any number of things could be harmful: we need to know how harmful, in what respect, how often will they be harmful etc.
Where does the blame lie here? Is the Guardian scaremongering? Nope. In the BMJ, Fewtrell et al write: ” US infants exclusively breast fed for six months, versus four to five months, were more likely to develop anaemia and low serum ferritin, which is of concern given irreversible long term adverse effects on motor, mental, and social development after iron deficiency.” This is reported in the Guardian as a quote with no embellishment – after all, it really doesn’t need any. It’s interesting and relevant (and scary) all by itself. The key difference in tone between the Guardian and the BMJ articles is that the former reports an academic review of evidence and the latter calls for a more thorough academic review of evidence. To be honest, I’m finding it hard to blame the journalist for frightening breastfeeding mums: in fact, I think the Guardian article is less scary than the one in the BMJ.
Finally, and just because it speaks to the name of this blog, let me quote the Fewtrell article again: “Apart from two randomised trials in Honduras, the studies were observational, precluding proof of causation for the outcomes examined, since residual or unidentified confounding may remain even after adjusting for potential confounders.” The detail matters. Study design matters. Data collection matters. The method is as important as the result. That’s why science journalism is often so unsatisfying: reporting method is much harder than reporting results.
I could have written a lot more about this, but I’m sure there will be another opportunity…