Sense about Science ? equipping people to make sense of science and evidence
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- The Welsh proposal to ban e-cigarettes in public places - following evidence trails
- Should we be worried about 'dirty' stethoscopes?
- A precautionary tale
- Antimicrobial surfaces derived from tea, wine and chocolate? Promising - but a long way off
- Ask for evidence on antimicrobial products and policies
- Q&A on plastic packaging with the British Plastics Federation
- Is soil on organic farms better at holding water in times of heavy rain?
- Politicians can't have it both ways when it comes to evidence
- Dallas Buyers Club and the myths of Aids activism
- Opportunities for two people to join us
Posted by Prateek Buch on 04 April 2014
The Welsh government is consulting on whether to include electronic cigarettes in the ban on smoking in enclosed public spaces. The ban is proposed in a White Paper that Health Minister Mark Drakeford suggests would help “reduce the harms to health caused by smoking.” The BMA has raised concerns about e-cigarettes normalising smoking and acting as a gateway to tobacco, which prompted us to ask for evidence. The proposed Welsh legislation cites the BMA’s advice, who must now respond to our enquiry. We’ll be asking Professor Drakeford similar questions about the evidence behind his proposals.
Speaking on Radio 4’s Today programme, Professor Drakeford said he had concerns that after a thirty-year effort to make smoking less acceptable, “e-cigarettes might reverse that tide and act as a gateway to conventional cigarettes.” The White Paper says the ban “reflects increasing concerns amongst public health practitioners that, as e-cigarettes become more popular, there is a risk that smoking behaviours could be normalised.” The UK’s Chief Medical Officer Dame Sally Davies also raised similar concerns, saying, “I am also worried about once again making smoking seem like a normal activity.”
How do these claims and concerns stack up against the evidence?
There is no evidence that e-cigarettes make smoking tobacco more attractive or socially acceptable, as the Royal College of Physicians note in their recent statement. Those who claim that e-cigarettes could re-normalise smoking are yet to produce any convincing evidence to show that they actually do.
What about the gateway effect – do people who ‘vape’ e-cigarettes go on to take up smoking? The evidence suggests not, as the Parliamentary Office of Science and Technology notes. A survey by Action on Smoking and Health London corroborates this, with less than 1% of never-smokers using e-cigarettes.
The Daily Mail cites a US study on the link between e-cigarette use and smoking conventional cigarettes as saying that the marketing of e-cigarettes “is promoting regular cigarette smoking among youth.” This study did indeed find that “e-cigarettes were associated with more, not less, cigarette smoking among adolescents,” but as this Forbes.com blog points out, not only does correlation not equal causation, it’s more plausible that the relationship runs the other way with heavy smokers using e-cigarettes as a way to help them quit.
Again, those suggesting that e-cigarettes could act as a gateway to tobacco haven’t produced evidence that they do, and the balance of the available evidence suggests that they don’t.
Perhaps the last word should go to Ash London: “There is little real-world evidence of harm from e-cigarettes to date, especially in comparison to smoking. In the absence of harm to bystanders, [we do not] consider it appropriate to include e-cigarettes under smokefree regulations.”
Posted by Volunteer on 31 March 2014
This is a guest blog by Laura Macdonald, Healthcare Scientist at the Infection Control Team, Health Protection Scotland.
You may have seen news stories that stethoscopes have been found to be ‘dirtier’ than doctors’ hands, and contaminated with the ‘superbug’ MRSA. So, should we be worried and if so, what is the health profession doing about it?
The stories are based on a study published in the journal Mayo Clinical Proceedings. In the study, samples were collected from doctors’ hands and from their stethoscopes after physical examinations of patients. The researchers found that doctor’s fingertips were the area most contaminated with bacteria, followed by stethoscope diaphragms. The researchers also found the antibiotic-resistant bacterium MRSA on doctors’ hands and stethoscopes after 38 of 50 examinations on patients known to be colonised with the bacterium.
This study isn’t the first to investigate this issue. And from the existing body of evidence it is reasonable to conclude that stethoscopes do become contaminated with bacteria after use, and could be a vehicle for transmission of pathogens in hospitals. But we can conclude no more than that.
The healthcare environment is not sterile, and we would expect to find bacteria on objects in that environment. However, most would cause us little concern. Intact skin is an effective barrier to most microorganisms so stethoscopes are considered to be ‘non-critical’ or ‘low-risk’ medical devices, because they are usually in contact with intact skin. Guidance from the CDC states that ‘virtually no risk’ has been documented for transmission of pathogens to patients through contaminated stethoscopes.
Of course, absence of evidence is not evidence of absence, and we must recognise the possibility of a risk to patient safety, however low, and act accordingly. This particular study recommends the need to ‘systematically disinfect stethoscopes after each use’.
Reassuringly there is guidance for decontaminating communal equipment such as stethoscopes. For example Health Protection Scotland advocate decontamination between patients, while CDC guidance recommends that, at a minimum, stethoscopes are decontaminated when visibly soiled and on a ‘regular basis (such as after use on each patient or once daily or once weekly)’.
We know, however, that compliance is not 100%. So, is there an alternative for busy healthcare workers? One study carried out in the intensive care unit and emergency department of a US hospital, explored the use of stethoscope covers impregnated with silver ions, which are believed to have antimicrobial properties. The results were disappointing – antimicrobial covers were found to be significantly more contaminated than uncovered stethoscopes.
The original study looked at stethoscopes immediately after doctors had performed examinations. Had the researchers taken samples after doctors had the opportunity to adequately decontaminate their stethoscopes (and hands!) before moving on to the next patient, the news headlines may not have been quite so alarming.
Posted by Volunteer on 28 March 2014
This is a guest blog by Dr Jon Otter, research fellow at the Centre for Clinical Infection and Diagnostics Research at King’s College London.
I have recently been looking at the potential for developing safe, effective antimicrobial surfaces. The focus of my interest has been hospitals and healthcare settings, but the potential applications of antimicrobial surfaces are much broader: consumer, food, laboratory and many more. So I was very interested to help Justine with the reply she received when she Asked for Evidence about antimicrobials surfaces derived from foods such as green tea, red wine and dark chocolate.
The discovery of this new type of antimicrobial coatings is a great story: researchers at Northwestern University, Illinois, detected a colourless residue left behind in kitchen sinks by certain foods. They then synthetically produced similar compounds in the laboratory and found that they had similar properties.
The paper describes the initial discovery and experiments to test the ability of two substances to kill Pseudomonas aeruginosa and Staphylococcus aureus. The paper contains a lack of experimental detail here: Where did they obtain the P. aeruginosa and S. aureus for these experiments? What concentration was applied? Was it a wet or dry inoculum? What was the contact time? The paper reports a ’30-fold’ reduction but this is moderate in disinfection terms and considerably less than most other candidates for antimicrobial surfaces.
The authors of the paper should be congratulated for performing such detailed work, but some of the claims in the accompanying news piece on the University’s website are bold. For example:
“The coatings innately have properties that are very beneficial to saving lives and keeping people healthy. Without any further modification, they can help prolong the life of a medical device, reduce inflammation in a patient and prevent bacterial infections”.
Whilst this may be true, it would depend on the coated medical device being shown to have safe and durable antimicrobial properties, and demonstrate clinical benefit through properly designed studies. The release also talks about ‘killing bacteria on contact’. The level of detail in the study makes it difficult to appraise the antimicrobial properties of the coatings. They clearly have some antimicrobial traits but this may be moderate compared with other antimicrobial surfaces.
Overall these polyphenol-based coatings are a promising candidate for producing antimicrobial surfaces. However, there is a long way to go before they are ready for widespread adoption for healthcare and other applications.
Posted by Tracey Brown on 28 March 2014
This is an article published on the Society of Biology blog on 28th March. You can read the full piece here.
Ahead of the Society of Biology’s upcoming Policy Lates event on the precautionary principle, Tracey Brown of Sense About Science gives her view on some of the issues surrounding the principle and its application.
What would you say if I suggested farmers start using a compound that could mess with your hormones in order to improve crop yields? I’ve conducted some pretty strict testing which indicates that it is safe but I can’t be sure; I haven’t got evidence that shows it is completely safe for you to be exposed to it over many years – I may never have evidence to put any hypothetical harm beyond doubt.
But that doesn’t matter, because the answer’s no anyway, right? We’re not going to take the chance. Now, how about if I told you that this compound would replace one that is persistent in waterways and which is being sprayed with increasing frequency because its effectiveness has dropped as the fungus it kills has evolved resistance? (All that extra spraying demonstrably harming ladybirds and other beneficial insects.) And, by the way, when I say mess with your hormones, I mean in doses that you’ll never be exposed to. In fact if you want to go into the detail a bit, what I really mean is that it has been shown to interact with the endocrine system, as many things you encounter on a daily basis do – including much of your food – and there’s no evidence that this particular interaction is harmful.
Continue reading this article here.
Posted by Chris Peters on 27 March 2014
Antibiotic resistance and ‘superbugs’ have in the last few years become a focus of research efforts and public health campaigns. The UK Chief Medical Officer called it a “ticking time bomb” and the World Health Organisation says it’s a major public health risk. When there’s a focus on an issue like this we often see products being promoted and policies put in place in response. Hospitals and GP surgeries are adopting new policies on hand-washing, on doctors’ white coats and ties, and screening patients for MRSA. Products from socks to banknotes, air conditioners to paint are marketed with claims that they will kill germs.
Are these claims evidence based or are we seeing public anxiety about superbugs used as a marketing tool? One way to find out is to Ask for Evidence. And lots of people have been asking and have let us know the responses they got.
Some of them have asked us whether the responses they get are good evidence. Which is where our Ask for Evidence partners come in. The Society for General Microbiology, the Society for Applied Microbiology and the journal Lancet: Infectious Diseases have volunteered their scientists to help tell us what kind of evidence they would expect to see for products and policies and to help people make sense of the evidence they get.
We’re putting these evidence hunting stories online over the next few days. So check back here tomorrow or follow #AskforEvidence on Twitter and Facebook to see what the evidence is behind antimicrobial stethoscopes, silver infused socks, bacteria killing curtains and more.