By Brian Carnell

Thursday, August 22, 2002

Ross Gittins wrote an excellent op-ed for Australia's The Age about one of the biggest problems with the way journalists report on risk research -- they inevitably tell readers and viewers what the increase in risk was, but rarely the absolute risk.

Gittins points to the recent study of oestrogen and progestin combination therapy that found a slight increase in the risk of certain forms of cancer among women taking the combination therapy.

As Gittins notes, it was widely reported that the therapy increased the risk of breast cancer by 26 percent, the risk of stroke by 41 percent, and the risk of heart attack by 29 percent. But, aside from the fact that these are extremely low increases in risk -- far below the 100 percent in risk that such studies should have in order to avoid the possibility of confounding circumstances -- knowing the precentage increases in risk is not very helpful without knowing what the risk was in the first place.

For example, another way of saying that combination hormone replacement theory increases the risk of breast cancer by 26 percent is that a woman on it has increased her risk of getting breast cancer from 1 in 333 to 1 in 263. Similarly, the change in risk of heart attack goes from 1 in 333 to 1 in 270.

Even worse is that in this case the authors of the study themselves highlighted the increased percentage of risk, and as Gittins writes, "You have to delve deep into their article to find the information needed to beat their true meaning out of them . . .So the primary blame oges to the authors of the article, not the journos who reported on it."

Both medical journals and journalists need to do a much better job of making clear just what increases in risk mean and discuss the limits of epidemiological research as well. Otherwise these studies end up creating a lot of hysteria and concern based largely on a lack of understanding by laypeople about what the study ultimately means.

Source:

When journalists juggle figures, the public is at risk. Ross Gittins, The Age, August 7, 2002.

Discuss (0 Replies) | Printer Friendly