Health in the media: the good, the bad and the ugly – 13th June

Posted on 13th June 2013 by David Carroll

Health is commonly reported in the media. Every day consumers of health information, whether they are academics or ordinary punters, are bombarded with information about risk. One thing that is often lacking, especially in the media, is effective communication of all this information. We at Students 4 Best Evidence want to become effective communicators of health information and this weekly blog hopes to provide you with the evidence behind the good, the bad and the ugly of this week’s health news.

The Good

The Guardian-Breast cancer screening not shown to reduce deaths, say researchers

Breast Cancer Screening is controversial, everyone seems to have an opinion on it’s effectiveness and those opinions are often polarized and vocal.

The Guardian[1], the Mail and others reported on research published this week in the Journal of the Royal Society of Medicine [2] the latest study by researchers at Oxford University adds to the evidence base. The quality of reporting varied but I’m glad to see coverage of breast cancer screening, it’s controversial and it’s emotive but I think we’ll only get around to tackling emotive problems if we learn to talk about them. Importantly the research is open access, this means that everyone can read it, even without a journal subscription. Open Access to research is important for us all it’s something I’m really passionate about (more on this later). The study itself was a time trend analysis; this is an observational study that describes characteristics of a population over time. They look at trends at the population level (rather than in individuals) through doing repeated cross sectional studies. A cross sectional study is observation of all of a population, or a representative subset of a population, at one specific point in time. This research looked at mortality (death) data to see whether mammographic breast cancer screening reduced deaths from breast cancer.

They found that women under 40 (who are not normally invited for screening) had the highest decreases in mortality rates over time.  In women aged between 50 and 64 years old, (the age group screening is normally targeted at) they also found significant decreases in mortality. The researchers concluded that the decreasing mortality is as a result of improved treatment for breast cancer, not screening. This is because the downward trend began either before screening was introduced or too soon after the introduction of screening for it to have an effect. This type of study design, like all studies has some limitations. In this research, direct comparisons of individuals who were screened with those who weren’t screened are not possible. The researchers were only able to compare mortality for women in age groups that were likely to have been screened with those who were unlikely to have been screened. This research does not rule out individual benefit of breast cancer screening, just that it is not detectable at the population level.

The Guardian and others reported on the controversy around breast cancer screening. The recent independent review [3] by Professor Sir Michael Marmot has done little to unmuddy the waters surrounding breast cancer screening. Professor Sir Marmot recently commented that the outcome that is of interest in trials of breast cancer screening is not breast cancer mortality but all-cause mortality and the previous trials may have been statistically underpowered to detect a difference in all cause mortality.

If I were in charge (which I doubt will happen), I’d probably stop the screening programme and do trials of breast cancer screening. If only it was that easy.

The Bad

Daily Mail-How worried should pregnant women be? As non-stick pans, make-up, air fresheners, even new curtains are said to put unborn babies at risk

Most news outlets including the Daily Mail [4] reported on a new publication from the Royal College of Obstetrics and Gynaecology called Chemical Exposures During Pregnancy-Dealing with Potential, but Unproven, Risks to Child Health [5]. The Daily Mail reported risks to mothers in pregnancy as:

• new cars
• housework
• non-stick frying pans
• soft furnishings
• food packagings
• paint fumes
• makeup and;
• pain killers

Advice given to pregnant women has gone from sensible to silly. These suggestions are unrealistic and unnecessary, including even avoiding shower gel while pregnant. The reports authors even acknowledge that “there is little evidence to suggest whether such chemicals do affect a baby’s development, or even if there is a risk to health” but they advise women to assume that a risk is present.

Making up advice based on no evidence while based on seemly good intentions, can be actively harmful and can lead to problems in getting the evidence in the first place. If we ever get the evidence, what if it completely contradicts the view of the Royal College in this instance? Then the public will yet again perceive scientists as flip floppers, unable to make up their minds about anything. This will be damning in the context of a public health emergency when we need the public to be able to trust doctors and scientists.

The Independent [6] even have an interview with the co-author of the paper in which she states that “for a while we’ve been concerned about certain chemicals that may be present in our environment, we do not know what the risks are but we wish to make women more aware of this, giving them the information that they find helpful’. I can’t imagine a world in which non-evidence based advice is helpful. Even the thought of a non-evidence based world makes me sad.

We could probably use this of an example of when not to publish, circulate around the health community but don’t publish it in newspapers and online for all to see. Pregnant women are bombarded with so much information perhaps it’s better not to publish advice until we’ve got good quality evidence to back up this advice. The authors want women to make “informed choices”. I can’t imagine women will make informed choices with light of an uninformed document.

All this advice is based on a safety-first approach. There is no credible evidence that any of the items listed above pose a threat to birth outcomes. I feel that this advice is unhelpful, unrealistic and alarmist. This type of news may also distract from the well-established harms in pregnancy and as a result of these guidelines, there is a danger that women who should have ended up more informed as a result of this document were instead more confused about pregnancy, worried and anxious. Since stress is a risk factor in pregnancy, it is one outcome the authors would have hoped to avoid.

Finally, this report has received so much criticism, both from clinicians/scientists and the media. There might be a danger of people dismissing some of the Royal College’s sound evidence based advice.

Let’s hope this doesn’t happen.

The Ugly

Sunday Express-Cancer risk of two beers a year

This headline on the front page of the Sunday Express [7] stated, “top scientists revealed drinking more than just two pints of beer a year heightens the risk of cancer”. This came from research presented by the group’s lead researcher, Professor Peter Anderson, of Newcastle University, at a major conference on cancer in Dublin. The slides are here and they state that the IARC assert that alcohol is a causal agent for cancers of the oral cavity, pharynx, oesophagus, liver, colon, rectum and breast. The following slide is a graph of relative risk of developing each cancer plotted against grams of alcohol consumption per day. The reference for this graph, “Corrao et al 2009”, doesn’t appear to exist on PubMed. When you look at the curves for each individual drinks, the relative risks for some cancers barely rise above 1 with consumption of 100g (10 drinks) of alcohol per day. I wouldn’t call such a weak association causal.

When his slides move to what I think is research, actually I’ve no idea if it’s research or not. There’s no original data that I can see or no references to work. Its just words on a slide.  His slides assert that the toxic threshold of alcohol (the dose of the drug that creates harmful side effects) is 50g (5 drinks per day), this figure is based on animal studies in which 10% with that dose have side effects. The next slide is where we get the meaty bit. It states that “the European Food Safety Authority guidelines on food and drink state that the exposure to carcinogens in food, exposure should be no more than one-thousandth of the toxic dose, which works out at 50mg of ethanol a day, about 20g of alcohol (2 drinks) a year”. From what I can tell, evidence does not back up this assertion.

In fact, the European Food Safety Authority has never assessed alcoholic drinks for safe exposure levels to carcinogens, so we cannot possibly know if alcohol is as carcinogenic as they claim to be. In fact, we cannot see the full results of their research. We as punters, cannot read the full methods and results of this research; we cannot critically appraise it for its worth and therefore cannot make up our own minds about this research. I think it was unwise for the Daily Express to report such a outrageous headline without much to back it up.

Overall, yes, excessive alcohol consumption is bad for you, yes we need regulation of the industry to effectively reduce population consumption but I don’t think reporting of this type is useful in tackling the problem of excessive alcohol consumption. I think this is more of a “fun sponge” approach than an effective one.

Boo you bores. I’m off to the pub.

References:

[1]Breast cancer screening not shown to reduce deaths, say researchers. [Internet]. The Guardian. 2013 May 30 [cited 2013 June 13]. Available at: http://www.guardian.co.uk/society/2013/jun/11/breast-cancer-screening-no-evidence

[2]Mukhtar TK, Yeates DRG, Goldacre MJ. Breast cancer mortality trends in England and the assessment of the effectiveness of mammography screening: population-based study. J R Soc Med 2013;106 :6234-242

[3]Breast screening review. [Internet]. Cancer Research UK. 2012 [cited 2013 June 13] Available at: http://www.cancerresearchuk.org/about-cancer/type/breast-cancer/about/screening/breast-screening-review-2012

[4]How worried should pregnant women be? As non-stick pans, make-up, air fresheners, even new curtains are said to put unborn babies at risk. [Internet]. Daily Mail. 2013 June 7 [cited 2013 June 13]. Available at: http://www.dailymail.co.uk/health/article-2337207/Pregnancy-Non-stick-pans-make-air-fresheners-new-curtains-said-unborn-babies-risk.html?ito=feeds-newsxml

[5]Chemical Exposures During Pregnancy: Dealing with Potential, but Unproven Risks to Child Health. [Internet] Royal College of Obstetrics and Gynaecology. 2013 May [cited 2013 Jun 13] Available at: http://www.rcog.org.uk/files/rcog-corp/5.6.13ChemicalExposures.pdf

[6]Food packaging and furniture: What to avoid when you’re pregnant. [Internet]. The Independent. 2013 June 5 [cited 2013 June 13] Available at: http://www.independent.co.uk/life-style/health-and-families/health-news/food-packaging-and-furniture-what-to-avoid-when-youre-pregnant-8644676.html?origin=internalSearch

[7]Cancer risk of two beers a year. [Internet]. Daily Express. 2013 June 9 [cited 2013 June 13]. Available at:  http://www.express.co.uk/news/health/406192/Cancer-risk-of-two-beers-a-year

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