Key safety, health and comfort issues Claus Curdt-Christiansen, International Civil Aviation Organisation Biography Dr. Claus Curdt-Christiansen (MD, DAvMed, FAsMA) has been active in regulatory aviation medicine since 1974. As Chief Medical Officer of the Danish CAA, he contributed to the harmonisation of the European JAA regulations. In charge of ICAO s Aviation Medicine Section for the last eight years, he has single-handedly kept the international regulations up to date. In addition, he has initiated important programmes in the context of civil aviation operations, in particular concerning psychoactive substances and laser emitters. In the 1970s, Dr. Curdt-Christiansen was instrumental in designing and conducting the first courses in aviation medicine for medical examiners in his country. In the 1980s, from the very beginning of the work of the JAA medical committee, Dr. Curdt-Christiansen was active in the development of the new JAA health regulations for all European licence holders, first as member of the JAA medical committee, and later as its secretary and vice-chairman. During his tenure as Chief of the Aviation Medicine Section of the International Civil Aviation Organization, Dr. Curdt- Christiansen has convened several international study groups with the objective of updating the international Medical Standards and Recommended Practices for personnel licensing. Under his guidance, specifications of the medical provisions in the context of flight safety were developed and adopted by ICAO. Visual standards for aviation duties, for example, have been rewritten and adopted, and scientific research into colour-critical aviation tasks and how they relate to licence holders colour perception has been initiated. Major work programmes on substance abuse have also been carried out, which resulted in the adoption of specific Standards on the use of psychoactive substances. Dr. Curdt-Christiansen co-authored and edited the Manual on Prevention of Problematic Use of Substances in the Aviation Workplace, published in 1995, to facilitate the interpretation and implementation of such Standards. Laser emitters and flight safety is another area in which Dr. Curdt-Christiansen s efforts have proven to be very successful. International regulations have been adopted and he has co-authored and edited Manual on Laser Emitters and Flight Safety, now ready for publication. In 2003, Dr. Curdt-Christiansen received the Theodore G. Lyster Award for outstanding achievement in the aerospace medicine. Presentation Summary This paper presents the current standpoint of the ICAO Secretariat on the effect of air travel on passenger health. It provides relevant background information and a survey of the comments received from Contracting States in reply to a State letter requesting States to provide available information about the possible effect of air travel on passenger health. ICAO s primary concern has always been the safety of aviation. However, the term flight safety has never been defined in any ICAO document. In 2001, the Air Navigation Commission agreed on the following definition: Aviation safety the state of freedom from unacceptable risk of injury to persons or damage to aircraft and property. However, this definition has not been adopted by the Council, so it is still unofficial. If adopted, a lengthy discussion on the semantics of injury to persons is bound to follow. The ICAO Secretariat believes that an important part of a flight operation is the provision of an adequate physical environment for crew and passengers, which is compatible with their well-being, the maintenance of good health and the avoidance of exacerbations in pre-existing pathological conditions. Insufficient monitoring or incorrect adjustment of the environment, in particular the air in the cockpit and the cabin, may endanger the health of the people on board, and thus constitutes a decrease in flight safety.
In recent years, there have been much public concern and intense media attention focusing on a possible link between air travel and deep vein thrombosis. There has also been increasing interest in cabin air quality, the in-flight transmission of contagious diseases, the effect of cosmic radiation, and the possible side-effects of various disinsecting procedures. In 2001, WHO and ICAO launched the WRIGHT Project, which researches the possible link between air travel and venous thrombo-embolism. At the ICAO Assembly in 2001, the ICAO Secretariat was instructed to look into the experience of Contracting States with medical conditions caused by, or believed to have been caused by, air travel. Contracting States were requested to provide available information about the possible effect of air travel on passenger health. The replies confirmed the opinion of the ICAO Secretariat that air travel presents no significant risk to the health of the vast majority of passengers. However, further research is required to establish whether specific elements of the aviation environment may be conducive to the development of specific pathological processes in certain passengers and crew members. Armenia Appendix Excerpts from replies to State letter AN 5/17-02/12 received from Contracting States The data of observations made by the Aviamed Medical Centre of the General Department of Civil Aviation of the Republic of Armenia regarding the effect of air travel on passenger health do not give us any grounds for assuming that there are negative effects of air travel on passenger health altogether. Australia [Australia is conducting] a major study into the threat posed by deep vein thrombosis (DVT) to long distance air travellers. Funded by the Department of Transport and Regional Services, the is being conducted by the Department of Health and Ageing, with expert advice from epidemiologists and public health experts, and involves data-matching of up to 10 000 medical and travel records held by Government agencies. It will reveal the proportion of the travelling population that has developed clinical DVT, or its more serious consequence, pulmonary embolism. The study has commenced and the preliminary results, which will be fully peer-reviewed, are expected later this year [2002]... (...) It is the first risk assessment study of its kind. Australia s decision to fund the data-matching study was based on the advice of health experts, who consider it will provide an excellent basis for deciding what further research is required, and whether we need to take additional steps to reduce the risk of DVT. Azerbaijan No cases of effect of air travel on passenger health linked to deep vein thrombosis are recorded in the medical facilities of the Medical Department Bahrain We are happy to inform you that the aviation medicine experts of the Kingdom of Bahrain have not recorded any case of the cases mentioned in your [State] letter. Belarus An impact of flight factors on passenger health is quite improbable. In the last 10 years of air transport, there have been no cases of negative effects of air travel on passenger health recorded.
Bolivia A review of medical reports on possible pathological effects in our country shows that there are no known cases that may be related to manifestations of thrombosis or thromboembolism in those passengers. Neither have there been any reports up until now [18 April 2002] about the transmission of contagious diseases during a flight or injuries to passengers and/or crew members from cosmic radiation. Canada Canada has had no incidents of adverse health outcome from air travel reported by civil aviation medicine staff in the past two years. The following general positions are provided by our Civil Aviation Medicine Branch: a) Air travel and deep vein thrombosis There is no known cause and effect relationship between [air travel and] this condition and its severe sequelae, pulmonary embolism. Passengers are advised to take precautions, particularly those at increased risk, however civil aviation medical experts are awaiting the results of proposed international research in this matter. b) Cabin air quality A review from many sources would indicate that under normal working conditions cabin air quality, while not ideal, is not a cause of significant symptomatology or disease in the vast majority of air travellers. It should be noted, however, that transport Canada, in partnership with Health Canada, is preparing to participate in an air quality study, in response to continuing health concerns expressed by both the travelling public and unions representing employees working on board aircraft. c) Transmission of contagious diseases There is no documented outbreak of dangerous infectious disease amongst air travellers. (...) The international medical community does not accept the suggestion that an aircraft is a possible incubator of transmissible diseases. d) Cosmic radiation There is no medical evidence that the present level of cosmic radiation, taking into account high altitudes, latitudes and sun spot activity has resulted in a burden of illness in passengers. Studies of aircrew have been confusing and inconclusive. There remains a concern for pregnant flight attendants and further research on this topic is actively supported by research and development funds from Transport Canada. e) Disinsecting procedures ion aircraft There is no generally accepted cause and effect relationship between these procedures and symptoms of disease in humans involved in air travel. Canada encourages and supports ICAO s efforts to highlight the concerns for passenger health at the international level. Chile Our State agrees that air travel may have minor or non-existent effects on the vast majority of travellers. However, this statement might not be valid for a minority of people (a very significant minority, in view of the mass nature of air transport in the world). We have seen, for example, heart failures in asthmatics associated with the dryness of the cabin air, hemolytic crises in persons with
sickle cell anaemia, deep vein thrombosis of lower extremities triggered by lengthy air travel and subsequent rest and dysautonomic arrhytmias associated with jet lag. The effects of air travel could be studied better only when there is coordination of research work that is prospective and multicentered with laboratories in the field (airports) to carry out, for example, cardiac monitoring, gas saturometry or vein Doppler echocardiography in groups of travellers who are at risk or particularly vulnerable before starting and after completing the travel. Cuba To date, there have been no reports of adverse effects on passenger health. Our national airline (Cubana de Aviación) is currently conducting a research pilot project that involves having a doctor on board for long-haul flights. We have no experience with respect to the transmission of contagious diseases (mainly respiratory tract diseases) during flight, nor with the side effects of various disinsecting procedures. Another point to keep in mind is that Cubana de Aviación will be asking travellers to disclose any diseases they may be suffering from at the time they purchase their tickets. Czech Republic Our airlines have not noted any positive link between air travel and deep vein thrombosis of passengers. But we recognize that some prevention is desirable. (...) Our specialized Institute of Aviation Medicine has had experience only with one case of deep vein thrombosis. It occurred seven years ago to one civil pilot. It was proposed that his illness might have started in connection with long distance flight, however after treatment he was able to return to his profession. He is under permanent watching of Institute and feels well. Ecuador... However, I can tell you that during the period from December 2000 to November 2001, the Airport Medical Services (AMS) unit, which reports to the Directorate General of Civil Aviation of Ecuador, provided medical attention to 1034 passengers and nursing care to 376 passengers on an out-patient basis through the Medical Assistance Section. The AMS medical log contains diagnosed cases of ototrauma, barosinusitis, aerodontalgia and, most frequently, black-outs caused by hyperventilation. We have no evidence in our country of passengers having suffered from thrombophlebitis or thrombo-embolism as the result of air travel. Between 1995 and 1998, Dimberg studied close to 5 000 passengers and reported 0.1 and 0.25 cases per thousand of thrombophlebitis and thromboembolism, respectively. He noted that these individuals had been assessed up to 30 days following their flight and that it could not be demonstrated that the flight had caused their illness; however, further studies involving a larger population sample are required.... Given the lack of information in our countries, it should be recommended that case and control-type epidemiological and demographic studies be undertaken; moreover, an administrative mechanism should be established making it mandatory for airlines to report the relevant information. Ethiopia We requested our national airlines medical service unit to provide us records of health problems suffered by their passengers during flying. No specific health problems as a result of air travel were given in their reply. In general the impact of air travel on
the health of healthy passengers is not visible in Ethiopia. This might be because patients do not recall and associate their ill health with the air travel that they had. France Statistics provided by Air France for the period 1 April 2000 to 31 March 2001 highlight the following points: Overall, a total of 2 774 medical incidents were recorded in flight in 2000-2001. None of these events were related to the hypotheses listed in paragraph two of State letter AN 5/17-02/12 dated 31 January 2002: cabin air quality, the transmission of contagious diseases, the effect of cosmic radiation, and the possible side-effects of various disinsecting procedures. This year, and in fact for the past five years, no cases of pulmonary embolism occurring during flight have been definitively diagnosed. It is true that this type of pathology, which is quite widespread among the general population (1.8 cases per 1000 per year), could occur once a flight has been completed. In 2000-2001, a few cases of phlebitis (<5), which undoubtedly existed prior to travel, were reported on board. (...) In conclusion, apart from pathologies that can be worsened by lengthy flights, jet-lag, fear of flying, alcohol and turbulence, none of the pathologies that can be caused by the physical/chemical conditions in aircraft cabins, as described in State letter AN 5/17-02/12 dated 31 January 2002, have been observed on aircraft in the Air France fleet. Germany At present there are no cases known in Germany where air travel has had an adverse effect on passenger health. Greece The following cases, which were reported since 1998 as related to passenger health and air travel (including airport-related incidents):... Asthma attacks (4). The three incidents were considered as a result of cigarette smoke - passive smokers. One of the incidents was fatal. Food poisoning (2) Claustrophobia (1) Deep vein thrombosis (1) Acoustic trauma (1) Iran...we have not had any adverse effect on passenger health, like deep vein thrombosis, till now [28 April 2002]. Jordan Jordan has no available information regarding cases where air travel is known to have had an adverse effect on passenger health. Passengers often exhibit medical symptoms such as fainting, nausea, and food poisoning but normally they are related to previous health problems. Mexico
...it is my honour to inform you that no medical cases such as those described in the [State letter] have been recorded in Mexico to date [13 May 2002] Norway Norway has no cases where air travel is known to have had an adverse effect on passenger health. Pakistan There has been no recorded incident of adverse effects of air travel on passengers health concerning deep vein thrombosis, specially during long haul flights. Paraguay According to data provided by the appropriate agency, I can inform you that in our country no relevant cases have been recorded concerning deep vein thrombosis among air travellers; nor have there been any reports of the transmission of infectious diseases during flight, the effect of cosmic radiation, or the side-effects of various disinsecting procedures. Philippines As per Chief Flight Surgeon s medical report submitted and Cabin Crew list of medical related flight reports covering the period January 2000 to December 2001 of Philippine Air Lines, there is no case of deep vein thrombosis encountered during air travel. Our flight reports on [260] stricken passengers will show that air travel, with its attendant stresses (reduced oxygen pressure, low humidity, cramped seating, uncomfortable temperature, noise, vibration, turbulence, carrying luggage, walking long distances, waiting in airport, etc.) can adversely affect a person s state of health. This is especially true for passengers with pre-existing medical conditions such as ischemic heart disease, hypertension, bronchial asthma, diabetes mellitus, emphysema, acid peptic disease, etc. A thorough pre-flight screening of such sick or incapacitated passengers and the provision of adequate safeguards on board (oxygen, special medical equipment, proper escort, stretcher, medicines, etc.) as determined by the attending physician, will help reduce in-flight emergencies and minimize flight diversions. Poland...after the analysis of all available data (records collected by cabin crew, airport doctors and aviation medicine experts in Poland) no evidence was found on the adverse effect of air travel on passenger health. Russian Federation According to information obtained from the medical institutions that come under civil aviation in the Russian Federation, no negative effects of air travel on passenger health have been noted. No direct relationship has been identified between the effects of flight factors and the state of health of passengers....(...) The prevention of the transmission of contagious diseases in relation to a large concentration of passengers in a limited space during a flight is a separate issue. In 1999, a case was identified where there was a passenger on the flight who had an open form of tuberculosis of the lungs. An X-ray and immunological examination was performed on the passengers who occupied 5 rows in front of and behind the patient s seat in the cabin. No infected people were found. No cases of deep vein thrombosis of the lower extremities were observed in passengers in recent years. There are no data on the side-effects of various disinfecting procedures on passenger health. Singapore We have not come across any confirmed case in our State where air travel is known or believed to have an adverse effect on passenger health.
Spain Note. The full text (in Spanish) of the study undertaken is contained in Sindrome del pasajero clase economica, which is available at MED section. Concerning the effects of air travel on passenger health, I am sending you herewith the study on the blood clot (thromboembolism) syndrom which was undertaken at the request of this DGCA......it should be stated that we have no reliable knowledge of any such case [thromboembolism] that occurred on Spanish airlines or in Spain. Tunisia Note. The full text (in French) of the study undertaken is contained in Morbidité des voyages par avion, which is available at MED section. Our study, which covers the period 1 January 2000 to 31 December 2001, includes 279 passengers who required the assistance of the medical team upon disembarkation from the aircraft to the emergency medical services department. The study found a clear cause and effect link between air travel and asthma, cardio-vascular diseases, late-term pregnancies [risk of premature birth], and ENT diseases (earaches, headaches). Turkey According to the reports of the relevant sections of the Turkish Airlines and the Atatürk International Airport, no case has ever occurred where air travel had an adverse effect on any passenger s health. Furthermore, the Turkish Airlines have reported that there had been neither a legal suit nor a claim against the company within the same context. Ukraine There have been no complaints from passengers about impaired health due to flights. United Kingdom The welfare of passengers is a matter that the UK Government takes extremely seriously. We welcomed therefore the House of Lords Inquiry s finding that air travel presents no significant risk to health for the vast majority of passengers. We also fully support the Committee s view that further research is needed to understand better the issues involved, and to ensure that passengers are given clear and credible advice. Much of the work we have undertaken following the House of Lords Inquiry has been directed towards achieving these objectives. Air travel can involve passengers spending long periods in what is for them an unusual environment, which some can find stressful. The process of checking in and boarding an aircraft often involves being in proximity to large numbers of people, which is in itself a natural source for the transmission of infections. These are clearly among the factors behind the association that is sometimes made between incidents of ill health and flying. But what we do not yet know is whether, and if so the extent to which, there are specific elements of the aircraft environment that can adversely affect passenger health. Without this understanding there is no basis for keeping systematic records of the numbers of passengers whose health has been adversely affected by air travel. We are not therefore in a position to provide a quantitative response to your request. United States The Federal Aviation Administration has no information on cases where air travel is known or believed to have had an adverse effect on passenger health. While there have been considerable anecdotal reports that various health issues are aviation related, we have not conducted, nor are we aware of, any sound scientific studies that clearly demonstrate that the various health concerns and issues referenced in your letter [Stateletter AN 5/17-02/12] are caused or are exacerbated by air travel.
Recently the FAA funded a congressionally mandated literature search and scientific review of the cabin air quality issue by the U.S. National Academy of Sciences. Their report, issued by the U.S. National Research Council concluded in part, that available information suggests that environmental factors, including air contaminants, can be responsible for some of the numerous complaints of acute and chronic health effects in cabin crew and passengers. The report went on to note, however, that the complaints tend to be so broad and non-specific and have so many causes that it is difficult to define or discern precise illnesses or symptoms. The Council recommends in part, that studies be conducted and data collected that allows analysis of the suggested relationship between health effects or complaints and cabin air quality. The National Research Council s report is currently being reviewed by FAA to determine a course of action. Yugoslavia...cases of DVT syndrome and infective diseases have not been registered (...) Passengers cannot be completely protected from this disease because it depends on their health preposition, but quality information may help in the prevention...