Tuesday, January 14, 2014

Medical writing; the limitations on reporting on medical trials and research

Dr Gill Jenkins BM, DRCOG, DFFP, BA

As a media medic I’m aware of the power of science and how it is reported. Front page stories often carry new information on what is supposedly good, or bad, for us. But by the nature of the limited space in most media for the full report, much of this information is incomplete, or not taken in context and can be confusing. Often unproven associations are made by people who don’t understand the science or the detail of the study. For people with health or body concerns, some stories could unnecessarily increase anxiety.

Looking briefly at a health story we can go through what has been said, or not said, by the science. For example,  I use the study ‘Increased Iron Levels and Decreased Tissue Integrity in Hippocampus of Alzheimer’s Disease Detected in vivo with Magnetic Resonance Imaging’, from the Journal of Alzheimer’s Disease, 2013.

This used radiographic imaging to measure iron levels in people with and without Alzheimer’s in a section of the brain called the Hippocampus, which supports memory function and can be damaged in the early stages of Alzheimer’s. It showed that people with Alzheimer’s had a higher presence of iron in the Hippocampus. A couple of resulting headlines ran ‘Alzheimer’s’ link to red meat’ and ‘Too much red meat may raise Alzheimer’s risk, scientists warn’.

From the headlines you might think there must be a link between red meat and Alzheimer’s but in the study the diet of participants was not considered and so the source of this iron was not identified, nor why people with Alzheimer’s have more iron in their Hippocampus. The study was not designed to do that, but was designed to simply find out how much iron is present. The study doesn’t explore what role red meat plays in Alzheimer’s. Some of the participants with Alzheimer’s may be vegetarian or have a diet low in red meat - Broccoli, lentils, sardines and pumpkin seeds are also rich sources of iron that could be a cause for the increased iron presence.

The connection to red meat by the media is poorly thought out guess work, with questionable logic. We do not know whether the patients smoked, drank excessively or exercised, for example, or whether there were other factors such as genetic reasons for the high iron deposits. When studies suggest behaviours could create the element of risk in developing an illness it accepts that it can make no significant claim. This makes the information a very small piece of a very big puzzle. I believe that incremental innovation is essential but we need to resist the temptation to reach a dubious conclusion on the information before the science proves that there is definitely a conclusion to reach.