Professor Michael Bagshaw, Dr Sarah MacKenzie Ross, Professor Helen Muir and Dr William Toff

10 JULY 2007

  Q112Chairman: Thank you for coming to give evidence to us at this session. I am sorry you are so far away but I hope the sound system will cope with that. Welcome, members of the public. There is a note outside on the remit of this Committee, if you would like to pick that up. I suggest that we start by you introducing yourselves and, if you wish, making an opening statement. Can we start with you, Professor Bagshaw?

  Professor Bagshaw: I am Professor Michael Bagshaw. I am Director of Aviation Medicine at Kings College London, a post I took up following my retirement from British Airways where I was Head of Medical Services for 12 years.

  Dr MacKenzie Ross: Hello, my name is Dr Sarah MacKenzie Ross. I am a consultant neuropsychologist at University College London and my area of expertise over the last few years has been toxicology, in particular looking at whether low-level exposure to organophosphates is harmful to health. I am funded by Defra for this work. The reason I am here is that I have seen a number of pilots over the last two years who report ill health.

  Professor Muir: My name is Helen Muir. I am the Professor of Aerospace Psychology at Cranfield University and my particular expertise is passenger behaviour and cabin crew behaviour in normal flight and also in aircraft emergencies.

  Dr Toff: I am Dr William Toff. I am Senior Lecturer in Cardiology at the University of Leicester and I have a long-standing interest in aviation cardiology since working for the CAA in the early 1980s. For the past six years I have been a member of the Scientific Executive Committee and one of the investigators for the WRIGHT project, investigating the link between DVT and air travel.

  Q113  Chairman: Thank you. Would any of you like to make an opening statement? If not, we will go straight into the questions. My first question is for you, Professor Bagshaw. You are the only professor of aviation medicine in the UK at present, as we understand it. Do you think research in this area is given sufficient priority? Has the position improved since the year 2000?

  Professor Bagshaw: I believe that awareness has risen and with that research is going on throughout the world; there is frequent reference back to the report of your Committee from 2000. In reality, it is fair to say that there is insufficient research in the UK. Her Majesty's Government contributed to the WRIGHT project on DVT, which you are going to hear about later, and as a result of your original report, the Aviation Health Unit was established at the Civil Aviation Authority whose remit is to oversee research, not to do research. If we look across the topics that were raised by the previous Committee, for example deep vein thrombosis, cabin air quality, fatigue issues, transmission of infectious disease and so on, the only substantive research we have had has been from the WRIGHT study from the World Health Organisation, and the research that has been done on cabin air quality has been supported by the European Union under the fifth framework and now under the sixth framework and this is pan-European, as opposed to UK-led. There is very little input from Her Majesty's Government into research in the United Kingdom and I believe that this is a pity. The fact that you have convened this committee suggests that there are still unanswered questions and I would like to see more focus. In my own department I am responsible for post-graduate teaching and I give a lot of input to advise on research, but I do not in fact conduct any research. My university does not fund research in civilian aviation medicine and there is no source of funding.

  Q114  Chairman: What is the worldwide situation with academic study of this problem?

  Professor Bagshaw: By "problem", are you indicating that there is a problem?

  Q115  Chairman: Looking into airline health in general and for passengers especially.

  Professor Bagshaw: The Aerospace Medical Association is the umbrella organisation internationally. The Air Transport Medicine Committee of the Aerospace Medical Association does oversee research and brings together the results of research and sponsors panels at the annual scientific congress. The International Academy of Aviation and Space Medicine also sponsors an international congress and papers are presented. In the past we have relied on the airline industry to provide the research. In my own time at British Airways, research was done into pilot morbidity and mortality, cosmic radiation, cabin air quality and so on. With the change in the structure of funding of the airline industry with the advent of the low-cost airlines, there is not the willingness or indeed the funding available to support that research, so we look to the United States. The ASHRAE Committee, the American Society of Heating, Refrigeration and Air-Conditioning Engineers, have a sub-committee on standards for cabin air and they are supporting research now at a number of American universities. Again, we look across the Atlantic for our data.

  Q116  Chairman: Do these people turn up at the international conferences and you participate in those conferences, so we have access to that?

  Professor Bagshaw: Indeed; yes. Both the organisations I mentioned are truly international. In fact I was president of the Aerospace Medical Association which indicates the breadth of the international dimension. The next meeting of the International Academy of Aviation and Space Medicine is in Vienna at the end of August/beginning of September and I have seen the draft programme; a number of passenger health issues will be addressed at that congress.

  Q117  Baroness Perry of Southwark: Could you tell us what you see as the really key findings of the WRIGHT project?

  Dr Toff: The aims of the study, as you know, were to quantify the risk of venous thrombosis associated with air travel, to clarify who is at risk and then to go on to look at possible interventions to reduce the risk. The primary finding was that overall the risk after travel in excess of four hours' duration by any mode is increased two-fold. So long-haul journeys by any mode, whether it be car, bus, train or plane, increase your risk two-fold. We know that there is an interaction with other risk factors, so that if you already have pre-existing risk factors, your risk will increase in a way which may be more than additive. What we found in the study was that, in addition to these synergistic effects being seen in all modes of travel, there was some suggestion that they were more pronounced in air travellers. We went on to look at mechanisms and specifically to answer the question as to whether hypobaria and hypoxia in the airline cabin might actually contribute to the risk of thrombosis, but we found no evidence of pro-coagulant changes attributable to the low pressure or the low oxygen in contrast to earlier smaller and uncontrolled studies. What we did find when we went on to do a volunteer flight study is that there is some element of the aircraft cabin environment that does appear to confer an increased risk, which fits with the epidemiological data, but we are not sure what that factor might be.

  Q118  Baroness Perry of Southwark: As I understand it, when they did this simulation, it did not produce any differences. Is that right?

  Dr Toff: The simulation in the hypobaric chamber consisted of 73 healthy volunteers. It included 12 people who were over the age of 50 and 12 users of the oral contraceptive pill. In the risk groups and in the general population there was no difference in the changes in blood-clotting parameters between a normobaric exposure and a hypobaric exposure. What we did not do was to look at the higher risk people, for example people who had combinations of risk factors such as pill use and an inherited thrombophilia. We had some difficulty recruiting such people. There are very few people in the UK who will routinely prescribe contraceptive pills to people who are known to have a thrombophilia. In the Dutch cohort who went on the flight study that was deliberately enriched and included 15 such people who did in fact have that combination of risk factors. What they found in the flight study was that the higher risk individuals did tend to show some increased coagulant changes in the flight compared with when they were studied after a similar exposure sitting in a cinema for the same length of time.

  Q119  Baroness Perry of Southwark: In the light of all this, what do you think should be done to reduce the risk to those vulnerable groups when they come to check in or when they buy their tickets?

  Dr Toff: It is important that we focus on public education, letting the public know that there is a risk and advising them of the general measures that they can take across the board such as avoiding excessively prolonged periods of immobility without even exercising the legs or getting up to walk around; that is not just for air travel, that is for any sort of journey. Going beyond that, we need to make sure that people who are at increased risk understand that they have risk factors and should be considering and discussing with their physician the possibility of other interventions that might be helpful in the higher risk group. Those might include, for example, wearing graduated compression stockings, use of a subcutaneous heparin injection in the highest risk people and possibly the use of mechanical devices, which are now available in small battery-powered versions, perhaps for higher risk people who are unable to take heparin. What we do not really know is the efficacy of those interventions in this setting. We have some data from a post-surgical setting and it is extremely important that we go forward with the second phase of the WRIGHT project which is designed to look at the efficacy of different interventions in this specific clinical setting.