Select Committee on Science and Technology Minutes of Evidence

Examination of Witnesses (Questions 120-139)

Professor Peter Burney, Professor Aziz Sheikh, Dr Graham Devereux and Professor John Warner


  Q120  Baroness Platt of Writtle: Does everyone agree that the prevalence of allergic disease will continue to increase?

  Professor Burney: As I was saying, I think it is probably true in the older age group that that is almost inevitable, but I would hesitate in one sense. It is very likely to be true for sensitisation, for the reason I have given, that the younger adult generations of people who are now going to get older have a higher burden of sensitisation, so I think that probably is going to happen. I would put a lot of money on that. I think the issue that follows from that, which we are less clear about, is what will happen to disease as a result of that increase in sensitisation. As I say, my guess would be that disease would also increase and be more of a problem, but there is less evidence on that.

  Q121  Baroness Platt of Writtle: You talked about the young compared with the old but would there be a difference on a gender basis, males and females?

  Professor Burney: I think much the same for men and women. As I said though, there are differences between men and women and I think, particularly in the child-bearing years, women have a high burden of asthma. The answer to your other question, what is happening in children, is that we just do not know and that is going to be very important, but it will be very important for the more distant future. If there is genuinely a decrease in sensitisation amongst these generations, this will then reverse the trend, but in another 20, 30, 50 years' time.

  Professor Sheikh: I think with this current generation of children, where the data in the UK show that between and 30 and 40 per cent are experiencing allergic symptoms, it is reasonably safe to predict that this generation will continue throughout adult life to experience allergic symptoms of one sort or another, so I think in the short to medium term the prevalence is going to be high and it is going to have an impact on all sectors of healthcare provision.

  Q122  Chairman: I wonder, Dr Devereux, if I could pick up on what you were saying previously about some of the animals and whether it is true to say that being brought up with cats may give you tolerance, but that there is a different cohort who are allergic and get very severe symptoms when in contact with cats and they may be in the same house living with those animals? Have we got two populations?

  Dr Devereux: I suspect we probably have. I suspect that the way the cat protection phenomenon is explained is that when you get exposed to cat allergen your immune system responds with a toleragenic response in that it tolerates the cat allergen, whereas you have got another group of people who, when they get exposed to cats, for whatever reason, genetic, environmental, diet, then develop an allergic response, so it is likely that you may have brothers and sisters living together and one may derive protection and one may derive harm from the cat.

  Q123  Lord Colwyn: We move on now to the burden these diseases are causing. The incidence has obviously increased a lot since the 1950s and I think I have read in my papers that it just about doubles every 10 years or so.

  Professor Burney: It doubles about every 14 or 15 years.

  Q124  Lord Colwyn: The written evidence we have got has highlighted the significant personal, social and economic impact of these disorders. Are there any key measures that you think perhaps the Government or other public bodies should implement to try and reduce this burden at home, at school and at work?

  Professor Burney: I will have a first go at this. I think it is very difficult, for the reasons we have given, to give very specific answers to that. Good healthcare would be good. Beyond that one of the things I would say is that it would be useful, given the high prevalence of disease, if this were something that was always considered by departments when they develop policy. I think that people tend to forget that there is this very large group of people who are specifically at risk, so I think that if all government departments, when they were developing policy, actually had a check, "Have we thought about what the influence would be on allergic people?", that would be good. As for giving very specific advice I would be pretty much at a loss to give strong advice at the moment.

  Dr Devereux: I think there is something that can be done. At the moment the allergy provision service in the NHS is not good. There is no allergist north of Manchester. There is no allergy service for the whole of Scotland or the north of England. What we have is a significant proportion of the population with allergic disease who are getting ad hoc advice from non-experts like GPs, respiratory physicians, dermatologists. These people are desperate for help and they are seeking help in alternative medicines, all sorts of things, so one thing could be to try and increase allergy provision so that a correct diagnosis of allergy is made so that the correct treatments can be instigated and the correct avoidance measures taken.

  Professor Warner: I agree with what Graham Devereux has said. I think that is the most important thing. There are some other issues though. It is about raising awareness across the whole of Government. For instance, recently the Department for Education has been recommending that the junk food which is sold in vending machines at schools should be replaced by nuts and peanuts as healthy foods. That is failing to consider the impact on the peanut and tree nut allergic child in that school. It is a question of joined-up thinking between different departments that might take account of this very common problem.

  Q125  Baroness Platt of Writtle: What about the problem of children with rhinitis and exams, because in two lots of evidence it said that they are achieving one grade less due to their allergy?

  Professor Warner: Yes, very much so. There is now good evidence for that. Exams are virtually always in the middle of the pollen season and that brings down grades appreciably. People have now done studies looking at results of mock exams, which are out of the pollen season, and comparing them with the results that have occurred in the real GCSEs and showing that pollen allergic children do drop a grade.

  Q126  Lord Colwyn: I am surprised to have read in our evidence that there is not any evidence that the increase is attributed to allergen exposure or even the famous house dust mite at all. The gaps in our knowledge could perhaps be dealt with by having better training at undergraduate level, courses for doctors and more specialist allergists. Would that solve it?

  Professor Sheikh: Undergraduate training is a key issue. We have been looking in detail in Edinburgh at our undergraduate training provision. For example, allergy diagnosis is not covered at all. Food allergy is not covered at all in the curriculum. Multiple allergies are not covered at all. This is a reflection almost certainly of what is going on in most other medical schools. At postgraduate level there is very little training provision at the moment. In response to your previous question, what else can be done, one of the pieces of work that we are currently doing is looking at anaphylaxis management in schools. Schools are, on the whole, at a loss to know how to deal with this problem. They are saying, "This is a healthcare issue; we are educationalists". GPs and, where they are involved, consultant paediatricians are saying that it is not their remit to go into schools. Children are therefore falling through the gap. For those with life-threatening allergies and with severe allergies one important step would be to think about case management. Case management now exists for a number of other long term disorders. Everything needs to be done within an evaluative context because there can be unintended consequences, but it would be one step forward to begin thinking of these as long term disorders, which the NHS historically has not done.

  Q127  Countess of Mar: Before I ask my question I should declare my interest because I am not a member of the Committee but I am allowed to come in on it. I am a farmer. I produce raw goats' milk, which we have quite a lot of custom for, and I also have an interest in toxic chemicals arising from organophosphate poisonings from sheep dip. Do you think that the Government's and the European Union's efforts now to control the proliferation of chemicals and chemical exposures, and particularly chemicals that are used in domestic situations, are worthwhile? I know that there is a lot of research now which is showing that the placenta is not as protective of the unborn child as it was thought to be. Do you think there might be some connection between the effects on the immune system that might have happened in utero and the subsequent allergies that are showing up? That is rather a lot of questions all together.

  Dr Devereux: The goats' milk—

  Q128  Countess of Mar: You need not answer that.

  Dr Devereux: No, no. The work from Switzerland, Austria and Germany showed that one of the protective effects of living on a farm was from consuming unpasteurised milk before the age of one. Whether you want to advocate that as a widespread measure I doubt because of the problem with tuberculosis.

  Q129  Countess of Mar: No, in fact I never recommend goats' milk to a child under the age of one and we know that our goats do not have TB.

  Dr Devereux: If you put it in context that is quite an interesting point. There is increasing interest in the possibility of environmental pesticides and things like that. There is this interesting work from various groups around the world showing that you can detect these chemicals in the blood of newborn babes and the exposure seems to influence the neonatal immune system responses. Whether these translate into current disease we are not really sure. I did look at one paper. The problem was that the levels of some of the chemicals have gone down, so it would be difficult to link. The other aspect of this is your cleaning agents thing. There is a study from ALSPAC associated with internal exposure to various chemicals and whether that needs to be all firmed up. Moving on to a different phase of investigation, we have looked at the allergen phase and most people would accept that probably the increase in asthma and allergy is not due to increasing allergens. Dealing with the hygiene and the dietary hypotheses at the moment, I think the things in the future are going to be the environmental pesticides, environmental chemicals and cleaning agents. That is where the research is going to be going to.

  Professor Warner: Certainly that is something where we need more information, but also we need to think about the other pollutants or other factors to which people are exposed where maybe there is a bit more evidence. We know that allergic sensitisation can be increased and the allergic reactions themselves can be increasing if you have simultaneous exposure with an allergen and, say, diesel particulates or ozone or nitrogen oxides, and so there are air pollutants that might be adding to the burden and certainly increasing the severity of disease. Pollutants may be also contributing to the increasing prevalence as well, although the data are a bit more tenuous, I think.

  Professor Sheikh: Can I come back on the raw milk point because there are data now from a number of studies which show that raw milk consumption may be protective, including data from the UK which have recently been published. The point here is that now we need prospective work and interventional work to understand this phenomenon better. One of the issues of relevance is that if we do introduce legislation around milk or other issues it is important, bearing in mind how little we know about early life influences, that that work is in an evaluative context. For example, raw milk sale, as you are no doubt aware, is banned in Scotland, so the scope for any interventional work is therefore very limited, but was there any evaluation put into place to look for unintended consequences which may have resulted from that ban? We need to be thinking much more broadly.

  Dr Devereux: The other thing is that people who purchase farm milk, unpasteurised milk, have different lifestyles from the rest of us and so it may not be the milk; it may be some other factor that they are exposed to or not exposed to. It may be a mark of lifestyle.

  Countess of Mar: It is quite interesting. Our customers come from a very wide range and generally they have children who are allergic to "dairy", as they call it. With my reading, apparently there are two different sorts of casein. There is alpha casein and beta casein, and I cannot remember which way round it is, but there is one that is found in goats' milk and Guernsey and Jersey cows, and the other is found in the black and white cows that nearly everybody's milk comes from. It may be that since the fifties farmers have tended towards having Holstein herds, the black and white cows, rather than the Channel Island cows, and there is a possibility there that it may have changed the metabolism somehow. The other one is the altered protein on pasteurisation, where the protein itself is altered on pasteurisation. Cheese-makers know that pasteurised milk does not make the same sort of cheese as unpasteurised milk.

  Q130  Lord Soulsby of Swaffham Prior: Can we talk about housing conditions and poor housing, and whether that contributes to the burden of allergic disease by way of, for example, increased dust mites, moulds and other environmental bacteria organisms? If there is anything there, should that danger in housing accommodation and other buildings be reflected in the Building Regulations?

  Professor Burney: Yes, I am sure that is true. I think there is quite good evidence that damp housing with mould causes problems, particularly for patients with asthma. Clearly, that is an avoidable risk that they run. That certainly could be important. We know that also, for instance, in some places, where you get very high build-up of, for instance, oxides of nitrogen from gas cooking—particularly with gas stoves—that can have an adverse effect on patients with asthma. That is quite easily remedied by having proper ventilation. I think it goes back to what I was saying about regulatory bodies always taking account of the fact that a very high proportion of the population is allergic, and I think Building Regulations should reflect that.

  Professor Warner: I think it is important, however, to distinguish between housing conditions that may contribute to the development of allergy in the first place. After all, everybody lived in damp, cold housing one hundred years ago and there was much less allergy, so it is not necessarily increasing the risks of being allergically sensitised. However, once you are allergic and have a problem there is no doubt that living in damp, cold housing makes your problems worse. For instance, in the United States, the inner city deprived population have infinitely more severe and even life-threatening asthma at higher prevalence than those living in better housing. So there is certainly a need to address that, but we need to think about whether in changing the indoor environment, this which might increase the risk of allergic sensitisation. I know that sounds a paradox but there are very different influences between creating the problem in the first place and aggravating it once it has occurred. There is, again, more work to be done to understand the indoor environment and how it contributes. By having energy saving we are creating tight homes which are increasing the levels of nitrogen oxides and volatile organic compounds which might be contributing to enhancing sensitisation in the first place. If we are going to have tighter housing for energy saving then we need proper ventilation systems with heat exchangers in order to achieve benefit for everybody.

  Q131  Lord Soulsby of Swaffham Prior: It is interesting what you are saying. The question naturally arises, are the people who are making proposed regulations aware of the dangers of energy saving and things like that? If they are not, how do you get that information to them?

  Professor Warner: Many years ago, I was involved in research with the Building Research Establishment, and at that stage they were very aware and doing quite a lot of work, but the BRE is not now predominantly government-run or sponsored; it is an independent organisation and I am not aware of what they are doing. There are other countries, notably Denmark, that have put quite a lot of work into housing design and its effect for allergy sufferers.

  Q132  Chairman: Can you clarify for me from your answer whether you are saying that low-allergen housing is actually unlikely to prevent allergy?

  Professor Warner: Based on studies so far done, the low-allergen housing is almost certainly not going to prevent allergy because you are not just reducing exposure to the allergen. There are other knock-on effects of reducing allergen exposure such as reducing exposure to bacterial products, which might increase allergy risk, with ventilation systems, and reduced exposure to irritants might reduce allergic sensitisation. So there is a bit of a balance: some things are perhaps not making any difference and others may actually be having some benefits. Studies that have looked at, say, reducing house mite avoidance in early life to prevent disease have shown that there is a reduced rate of early wheezing illnesses not associated with allergy, but later with no difference or, maybe, marginal increases in allergic-associated wheezing.

  Q133  Viscount Simon: For the last 15 years or so, I think it is acknowledged, there has been a year-on-year increase in hospital admissions for anaphylaxis, which suggests an underlying change in the epidemiology of this sort of allergic emergency. What can be done to reduce the number of people admitted suffering from anaphylactic shock?

  Professor Sheikh: You are absolutely right the data show very dramatic increases over the last 15 years or so, and these are year-on-year increases, and they continue. There are three issues that need to be considered primarily. One is that in those presenting with acute anaphylaxis in hospital accident and emergency departments we know that very many of these patients are still getting sub-optimal care, so many of them will still not receive adrenaline, which is a potentially life-saving treatment; they will often get other forms of treatment, in the form of antihistamines or steroids, and here there is emerging evidence to suggest that we may actually be doing more harm than good in those cases. One of the things we need to be doing is developing a far more secure base around how we manage this in an emergency context and seeing if that will improve outcomes. That is challenging to do because this is a life-threatening emergency, so it needs an appropriate regulatory framework and it needs ethics committees to think more flexibly than they have done hitherto. That is one issue. I think the second issue is about long-term provision for those who have a history of anaphylaxis. We have tended to think about this as an acute problem only, but this condition has life-long implications and multifaceted implications. One of the things we could be thinking about is developing anaphylaxis long-term management plans, as is now common in some other allergic problems, such as asthma or other chronic disorders, and that needs to be done, but again within an evaluative context. There needs to appropriate incentives in place in general practice, but I think with a will we could probably devise these. That would commit us to identifying the allergens that are responsible for provoking anaphylaxis so patients know how to avoid these products, and also training them in appropriate emergency provision if they do get exposed. Taking that twin-strand approach would probably help us in reducing some of this burden.

  Q134  Chairman: In your response to Viscount Simon you were saying that the current management where they are not going to use adrenalin early may be doing more harm than good. I wonder if you could expand on that.

  Professor Sheikh: Certainly. Adrenaline is internationally recognised as the treatment of choice in anaphylaxis. Unfortunately, very many patients who present with anaphylaxis still do not receive adrenaline. Having said that, there have been very few empirical studies on which to base the decision to treat with adrenaline, so we do not know the correct dose to be using, we do not know what the correct route of administration is, and we do not know when is the appropriate time to give the next dose of adrenaline. So there are massive gaps. What people do get when they walk into an A&E department is antihistamines, and they will be given antihistamines intravenously, typically. There are some data which suggests that, particularly in hemodynamically compromised individuals, they may be increasing the risk of arrhythmias in these patients. They are also often getting steroids, which, if given intravenously, again, are going to have virtually no impact on the acute illness. Again, there are no real scientific data on which to base those treatments, so in such a case we need to be rethinking some of these guidelines. I am, together with colleagues in Canada and the US, involved in those discussions, so I think we will get progress internationally in the next few years.

  Q135  Lord May of Oxford: Under the heading of hospital admissions I want to ask a follow-up that goes a little wider, although it does relate to this. One of the background papers we were given is a report from the Office of National Statistics, by the authors Gupta and Strachan, and it shows that there has been a decline in hospital admission rates in relation to asthma among children in the last decade, and it goes on to say: "after three decades when prevalence studies, primary care contacts and hospital admission rates all suggested a rise in the burden of asthma in children". They became disassociated in decade 1990 to 2000 (possibly, it has been suggested, it is just more widespread use of preventers reducing the incidence) but then they go on to say: "At a regional level in England [and they quote studies] there was a very poor correlation between admission rates for asthma [which have gone down] and the prevalence of wheeze (even of severe wheeze) [which had gone up] among children, [and here comes the question] suggesting that referral and admissions policies, rather than the incidence of acute attacks, are potentially the important determinants of asthma admission rates". So I have two questions: the first is—and I imagine you are quite sure but it would do well to affirm it—that the rise in admission rates for anaphylactic shock is real and not a change in policy. But then I would like to cheat and ask a second question: do you have a comment on the thing I have just read, which really is quite an important statement if true.

  Dr Devereux: Fundamentally, the person who decides whether a patient should go to the hospital is the GP, so referral patterns are very important. That is what decides whether a patient gets referred. I personally feel that the reason why admission rates have gone down is because GPs are managing asthma much better than they used to: the increased use of preventative medication, as you have just said, asthma plans at home, patients are basically able to take their own steroids when they get symptoms, they have peak flow-meters at home, it is far more controlled and you get fewer patients coming in who have just acutely deteriorated. Most people are able to manage it at home and GPs are increasingly confident about their ability to manage asthma at home. As you said, they are more confident, the medication and management plan is in place and fewer people are getting referred.

  Q136  Lord May of Oxford: So the severe wheezing attacks that previously would have had them admitted are now managed at home.

  Dr Devereux: Yes.

  Q137  Viscount Simon: Following what Professor Sheikh was saying, I have two questions: one is personal, I am afraid to say, and the other one is more to do with this inquiry. You were talking about cetirizine and allied medicines and, also, adrenalin. I take a huge doze of cetirizine every day of the year and I carry adrenalin with me. From what you are saying, should I use the adrenalin in an emergency? The second question, which is the general one, is do you think it would be worthwhile starting or instituting a national anaphylaxis surveillance programme?

  Professor Sheikh: Maybe I can try and take both of these questions together. In terms of your personal question, if you are experiencing symptoms of anaphylaxis then certainly use your adrenalin and get some help. I think everybody would be in agreement about that. In relation to hospital admissions, hospital admissions are the tip of a clinical iceberg, so studying those is subject to all sorts of potential variables. However, we are on reasonably firm ground, when we have got data pointing in the same direction irrespective of the data source, as in asthma for example—we know that hospital admissions are declining and we have got a pretty good idea of what is happening in general practice as well—really what we are seeing is a decreasing burden, or at least a stabilising in the disease burden. In relation to anaphylaxis, what we are seeing is that hospital admissions are going in a certain direction, very clearly. When we have investigated the possibility of diagnostic transfer taking place, and it seems that is unlikely to be taking place, we have looked for regional differences and it seems, again, that there are similar patterns all across England. We have looked across different age groups and, again, it seems that there are similar patterns in most age groups. In terms of primary care data, which are as yet unpublished but hopefully will be within the next few months (once I have finished with this I can get back to writing the paper), what we see there is that there is improved diagnosis taking place in general practice but, over and above that, there is an increased number of people with anaphylaxis. Failing that, the only next step that remains in unpicking this jigsaw is going back and doing some validational work, so looking at people who are admitted with anaphylaxis and then extracting some of their individual case records, subjecting them to a panel of experts and seeing to what extent the data are valid. That work, again, is on my agenda—we need to do that. In relation to surveillance, with these numbers and this rate of increase then surveillance is entirely appropriate. Our estimates, at the moment, are that in England there are some 38,000 people (these are unpublished data) who have had a history of anaphylaxis at some point in their lives. These are still relatively small numbers, so a surveillance programme for anaphylaxis could prove feasible. Some kind of longitudinal tracking of a sample of these individuals would help us to far better understand the epidemiology of this condition. I am part of an international group looking at the epidemiology of anaphylaxis, and you are right to point out there are massive gaps, but in the UK we are probably the most developed in terms of our understanding.

  Professor Warner: May I make some comments? Firstly you are not doing yourself any harm taking regular cetirizine and you might actually be helping some of your allergic manifestations, which is rather different. In relation to the increasing rates of severe, acute allergic reactions, particularly in relation to food allergy—clearly there has been a dramatic change in people's eating habits and what kind of foods they are accessing. It would be relatively easy to avoid peanuts if everything you ate was cooked yourself having bought fresh food in the market and from the butcher. Of course, that is not what happens now and people are buying products that have gone through a whole series of processes and been manufactured and packaged. Under those circumstances the potential for there to be unexpected peanut within those products, unfortunately, is significant and creating a problem, and it is a nightmare for sufferers. They now have a poorer quality of life than someone with diabetes requiring insulin every day. That is now well established. It is a question of, maybe, changing our eating habits and raising awareness that ought to, in the end, have an impact. Yes, we have to understand why the whole problem has increased but, at the same time, to help people that are suffering now I think there are things we can do.

  Professor Sheikh: The degree of distress that some young people experience by being confronted with labels saying "may contain traces of nut" is something I think we underestimate. Let us turn that on its head. I think there is a market now for products which are guaranteed to be nut-free and similar other products which are guaranteed dairy-free, for example. Some work needs to be done to look at that and that would, again, be something that would be very useful to a lot of people.

  Chairman: We have quite a lot of questions still and I am aware of the time, so I think we are all going to try to be concise with our questions and appreciate if you could with your answers. It would be really important to get through questions on primary prevention and research.

  Q138  Lord Taverne: Turning to research, in an area where there is so much uncertainty, what are the most promising areas of research into primary prevention? What would be likely to produce best value for money? For example, would it be diets of pregnant mothers, pre-biotics, pro-biotics? What is your view?

  Dr Devereux: I am very biased. I think there is increasing evidence that we should look at maternal diet during pregnancy. I am being encouraged by various people to actually go ahead and try and do an intervention study. Whether I get funding for it or not—it is clearly going to be a hell of a job to get funding. Pre-biotics certainly. If you speak to the people who make pro-biotics, they think the case is made, with a couple of well-designed intervention studies in pregnant women showing a reduction in eczema with pro-biotics. So I am biased, and that is my biased view. I would go for maternal diet, but I am sure other people will go for other things.

  Professor Warner: I would agree. I would put diet as number one, although I prefer to call it nutrition rather than diet because it is nutritional enhancement rather than avoidance. After that I would still focus on pre-biotics, not pro-biotics—I do not think the case has been made for pro-biotics. I think the interactions of all the different organisms in the gut are very complex but pre-biotics look more promising. After that it is some form of immune modulation using other microbial agents to induce an appropriate immune response. Those are the three areas I would focus on.

  Q139  Chairman: I wonder, too, what you feel about maternal smoking and the effect of maternal smoking on the risks of a child developing allergy.

  Dr Devereux: It is well known and accepted; it is well documented and I think everybody accepts that.

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