Abstracts Submitted for Conference on Air Travel and Health

Cosmic Radiation and the Risk of Cancer in Astronauts

Aviation has been one of the defining technologies at the heart of mankind's development from the Wright Brother's first flight to the delivery of the Atomic bombs that ended WWII to the landing of the first man on the moon, and finally to that fateful September day. Aviation has changed the course of history since its inception. The public health significance of flying is paramount not only due to its historical significance but also due to the drastic changes that it has brought about globally. Aviation has greatly strengthened population mixture, social ties, conflict intensity, economies, communication, etc…..

In previous literature it has been suggested that exposure to higher levels of cosmic radiation in commercial flight crews may increase their susceptibility to certain types of cancer. To further investigate the link between cosmic radiation, cancer and its implications to commercial aviation it would be prudent to utilize a population that is at an extreme exposure level of cosmic radiation. The appropriate hypothesis would then be that those individuals at this exposure level will have a higher risk of cancer. Thus, I propose an international retrospective-prospective cohort study of all past, current, and future Astronauts and Cosmonauts. The exposed group will be defined as having spent any time in space, while the unexposed group will be those individuals who were trained for space travel but never actually undertook a mission to outer space.

"This is your Captain speaking" - The Pilot's role in counteracting the effects of Prolonged immobility in Air travel


Thromboembolic events following air travel do occur and have been reported several times in the literature. A few of the risks factors often listed are: immobilization, prolonged travel time, alcohol (diuretic effect), decrease fluid intake, direct pressure on leg veins and pre-existing medical illness or other predisposing conditions. Special attention is placed on the fact that (in Europe) thromboembolism following air travel occurs in young healthy individuals with no previous medical history. In this regard, airlines have recently inserted a few lower limb exercises on in-flight safety instruction handouts. Some airlines have also released education materials on their websites on the health risks of air travel. Despite these efforts, thromboembolism after air travel remains a significant medical concern. The purpose of this study is to evaluate the pilot's role in counteracting the effects of prolonged immobility in air travel. Does the pilot's announcement of instructions and recommendations on mobility via the in flight PA system at the beginning of a flight increase mobility among its passengers in the aircraft cabin?


The study will be conducted on passengers on randomly selected scheduled airline flights of more than six hours duration. All participants (in all randomly selected airline flights), in both the control and prevention groups will be handed instructions on in- flight exercises and mobility as well as information on DVT and air travel. The participants in the intervention group (collectively, per aircraft) will receive a five-minute announcement via the in flight PA system from the pilot about counteracting the effects of prolonged sitting and immobility through carrying out lower limb exercises and encouraging mobility within the aircraft cabin. Main outcome measure will be increase in mobility and/or physical activity among passengers in all cabins of the commercial aircraft.


As in smoking cessation, where physician's instructions and recommendations are regarded as superior to written patient education materials in effecting change in behavior, the pilot's role in counteracting the effects of prolonged immobility during air travel is deemed necessary to produce similar effects.

First Class: Is it Worth It?

The airline industry "pampers" their first class customers. Every day, thousands of passengers board thousands of airplanes worldwide and opt to fly first class due to the "perks" that they receive during the flight. For an increased ticket cost, first class passengers are able to enjoy spacious seating, a nice meal, and take advantage of the unlimited free champagne that is offered to them. It is this champagne, coupled with the extremely dry in-flight air of the cabin that has the potential to deteriorate the health of first class passengers on a long flight. The possibility of dehydration among first class passengers becomes quite real, especially if they consume large amounts of the free, unlimited champagne that acts as a diuretic, and exacerbates dehydration.

A study that partners a research institution with a local airline is underway to assess the prevalence and severity of dehydration among first class passengers based on the amount of champagne or other alcoholic drinks consumed during flight. First class passengers will be interviewed near the end of each flight that lasts 5 or more hours in duration. Flight crew will administer the questionnaire. Questions regarding number of alcoholic beverages, number of restroom visits, and feelings of dehydration, will be collected on all first class passengers. The data will be analyzed to discover if there is an association between number of alcoholic drinks consumed and severity of dehydration. In-flight dehydration may decrease markedly if alcohol intake is limited. With the possibility of improved health among the flying public, first class travelers may want to reconsider that expensive ticket.

Health Problems Associated with Seating On Long Distance Flights

Commercial air travel has increased dramatically in the last 25 years, which has resulted in increased numbers of passengers traveling. In 1995, approximately 1.4 billion passengers flew. There are very few contra-indications to flying in commercial jet aircraft and even passengers with medical conditions travel regularly without incident. Air travel is becoming increasingly more accessible to people both through the availability of cheap flights and because the airlines now cater to individuals of all ages and disabilities. The wide bodies of many new aircraft permit the airlines to have very flexible seating options. Airline operators currently have an important role in determining the comfort and spaciousness of the seating in their aircraft. Edema is the presence of excessive fluid in tissue spaces. Sitting still for a long period of time may cause the lower limb edema and therefore passenger discomfort. Experiments on 12 healthy volunteers in mock up of an aircraft were monitored during simulated 12 hours flights at atmospheric pressure, chosen to represent day and night flying. The results illustrated that the swelling was greater in night tests and increased proportionally with duration of sitting. The purpose of this study is to develop a method to reduce edema of the leg on long distance flights and make flying more comfortable and enjoyable.


5 commercial airlines that travel overseas will randomly be selected. Survey questions will be distributed among 500 hundreds healthy passengers from those airlines which will also be selected randomly. Then a physician will evaluate swelling and any other symptoms that may cause discomfort before they board their plane. Those individuals will be randomly divided into two groups. First group will be control so they are going to be observed after 12 hours flight and the same physician will evaluate them for any sign and symptom of swelling and discomfort. The other half will do repeated leg exercise and will be asked to move their leg during the flight as much as possible. Then the same physician will evaluate them after 12 hours of the fly and will exam them for any swelling and discomfort. Survey questions are as follows: Regression analyses will be used to analyze the data for significant differences between the groups.

The Increased Risk of UTIs in Certain Passenger Populations Flying Post September 11th


Long flights have been shown to adversely affect passengers' health. This was established in a number of isolated cases where passengers developed deep vein thromboses after sitting for prolonged periods of time. The terrorist events of September 11th, 2001, have consequently prompted additional discomforts to be enforced during air travel, in order to ensure safety precautions. One of these safety measures discourages passengers from forming a line to use the airplane's restroom(s). Thus, passengers must determine from their seats if the restroom is vacant. During a long flight, this recurring hassle can simply discourage or postpone a passenger from using the restroom facility. A delay in accessing the lavatory may inadvertently cause urinary tract infections (UTIs) in certain passengers who are already predisposed to UTIs. Passengers who may be at increased risk for UTIs include: children who retain urine for longer than usual periods of time, passengers with BPH (benign prostatic hyperplasia), passengers who are wearing a scopolamine patch to prevent nausea, and those who take diphenhydramine before or during the flight (often to promote sleep). In all of the aforementioned examples, the anatomy (small ureters in children), the disease state (BPH), or the anticholinergic properties of the medications (scopolamine, diphenhydramine) can put these passengers at increased risk for UTIs. The aim of this study is to ascertain if post-September 11th events, have triggered an increased frequency of UTIs in specific passenger populations, on flights of greater than eight hours in duration. If there does, in fact, prove to be a statistically significant difference, then a subsequent research question that needs to be asked is: Would the prophylactic use of antibiotics in these particular populations be a cost-effective and reasonable solution, or would other options need to be explored?


A questionnaire would be randomly administered to passengers who flew shortly before September 11th and those who flew in the months after September 11th. Recall bias should not be a substantial confounder, since patients who are asked to recall a particular event (i.e. UTI) which they are more likely to remember, given that it is associated with a date of travel. The questionnaire would be designed in such a way so as to determine whether or not a causal relationship exists between the date of travel and the occurrence of the UTI.

What is the effect of flight over different time zones on diabetes mellitus and insulin administration protocol?


Flying is becoming very common activity for many people. In fact, more than three million people fly every day and 1.3 billion people per year are flying on commercial flights. Also, diabetes mellitus is one of the major chronic disease of current era. Approximately 14 million people in the U.S. are diabetic and quite a few of them depend on insulin injection for the optimal control of blood sugar. The improper control of blood suger will result in the acute complications such as hypoglycemia, non ketoic coma, diabetic ketoacidosis or infections. The protocol for insulin administration is determined by patients' life style, blood sugar pattern and meal schedules. However, only very few studies are available to date about the effect of flying to the different time zones on patients with diabetes mellitus and optimal way to adjust insulin administration.

Study is done in two phases.
Phase I

Method: retrospective cohort with questionnaire
Phase II

Method: randomized control trial

Cortisol Levels and Long Flights


The number of passengers that fly on international flights and the duration of these flights increase each year. This means than more and more people are being exposed to jet jag (circadian rhythm desynchronosis), when traveling on long flights, especially when passing through several time zones. Jet lag is not just a nuisance but can give rise to serious health problems. Symptoms of jet lag significantly impair the performance of business travelers, sportsmen and pilots, leading to fatal accidents with loss of many lives. Exposure to chronic jetlag induces prolonged secretion of the body's stress hormone cortisol. Prolonged excess exposure to cortisol leads to multi-system structural changes, which are permanent. Changes in the brain cause cognitive impairment, increased reaction time, reduction in spatial skills and impaired short-term memory. Changes in the cardiovascular system give rise to increased risk of cardiovascular disease. The proposal is to carry out a cross-sectional study to understand patterns of elevation in cortisol level in response to jet lag.


A cross-sectional study will be carried out amongst healthy international travelers, whose salivary cortisol will be estimated immediately after an international flight, on two occasions six hours apart. Cortisol will be estimated in the same person 5 days after the travel, at the same time of the day, in the same way. The cortisol level at these two different times will be compared. Degree of differences between the two cortisol levels will be correlated to factors such as duration of international air travel, whether the flight was east-ward or west-ward, whether the passenger slept on flight and whether the passenger was male or female. This will lead to recommendations to improve adaptation to the new time zone, improve sleep patterns, reduce fatigue and improve performance.



Deep vein thrombosis (DVT) is a condition in which a blood clot forms in the vein and impedes the flow of blood. DVT is the third most common cardiovascular disease ranking behind acute coronary occlusive events and strokes. DVT affects approximately 2 million Americans per year. DVT can lead to pulmonary embolism, which is estimated to cause 34,000 deaths a year. The true frequency of DVTs for air travelers is unknown. I propose to do this study to determine the frequency of DVTs for air travelers. This research will define the risk of DVTs to air travelers.


Study Population:
Cases - flights >= 4 hour duration; Controls - flights < 4 hr duration

Hypothesis: passengers flying < 4 hours duration will have less DVTs than passengers flying > 4 hours duration

Flights would be randomly selected.

Data to be collected on all persons flying on the specified flight:
Incentive to participate in study: free first-class round-trip airline ticket would be given to the person selected randomly from the participants of that flight

Air Rage and Nicotine Deprivation

Air rage has been estimated to have increased 15% since the events of September 11th.

"AIR RAGE, like road rage, is the inability to cope with the challenges of congested traffic. Just like aggressive driving and road rage, air rage is so common that most travelers are unaware that they have it. It's just part of the background feeling that goes along with the stress of travel and transportation."

Some of the causes of increased air rage are most likely frustration caused by increased delays and a general increase in anxiety regarding air travel. People whose normal social inhibition against aggressive behavior has been weakened by the increased stress of long delays, uncertainty over newer regulations, general increased anxiety and perhaps alcohol can regress into unacceptable behaviors. In some cases, however, air rage has been directly attributed to tobacco use. Nicotine is a highly addictive drug. Nicotine withdrawal can cause an individual to become irritable and edgy. Many smokers are also accustomed to using cigarettes as a mechanism to relieve stress.

This abstract presents preliminary results of a study on the use of nicotine patches on lengthy airline flights to counteract withdrawal symptoms associated with prolonged smoking bans. Heavy smokers [greater then 20 cigarettes per day] traveling on flights expected to last greater then 2 hours were recruited to participate in a double blind study of flight stress and nicotine. Consenting participants were randomized to nicotine patches vs identical appearing placebo patches. All participants filled out pre and post flight questionnaires accessing their stress levels, alcohol consumption, flight delays, and general travel complications [lost baggage etc.].

Deep Vein Thrombosis and Seating

The so called 'economy class syndrome' might result in deep vein thrombosis, a condition in which clots develop in the deep veins of the leg. It usually does not happen in business or first class air travelers.

In 1986, Sarvesvaran R et al. reported that of 104 natural deaths happened during the flights, 12 occurred due to deep vein thrombosis. In 1999, Ferrari E, et al found that of 160 cases of deep vein thrombosis, 39 had recently traveled. However, only 9 were related to flying while 28 followed a trip by car and 2 by train. Thus the controversy regarding the economy class syndrome has been existed.

A wide variety of factors may influence an individual's likelihood of developing deep vein thrombosis such as gender, age, family history of blood clots, certain blood diseases, recent surgery, physical activity (those who are more physically active during the flight are less likely to develop deep vein thrombosis). However, it is not easy to determine whether the passenger was physically active during the flight.

I would like to test whether those passengers who have window seats and thus felt less comfortable to walk are more likely to develop deep vein thrombosis. I propose to conduct a case-control study where cases will be identified among those passengers who developed deep vein thrombosis after the flight. The rest of the passengers of the same flight will become a control group. To increase sample size, we might be needed to evaluate study subjects from more than one flight. Some adjustments during statistical analysis (gender, age, family history of blood clots etc.) will be made.

Is there an Increase in Prevalence of Fibromyalgia syndrome in Flight Attendants?

Fibromyalgia is a chronic pain syndrome, mostly affecting women, with the presenting symptoms of diffuse myalgia/arthralgia, fatigue, and non-restorative sleep. Estimated prevalence of fibromyalgia syndrome in the general population in the United States is 2%, which increases with age. 80% to 90% of patients have been female, and the mean age has varied from 30 - 60 years. Flight attendants are likely to be at higher risk of having fibromyalgia syndrome due to the nature of the occupation. The potential risk factors are jet-lag, little room for movement or lack of physical activity, increased stress from change of environments, increase anxiety from recent terrorism, and being away from family members frequently. Pain is the most important determinant of "severity", but psychologic status and functional disability contribute independently to severity. Previous studies on general populations reported varying disability rates from 9-44% with regard to function in fibromyalgia.

My hypothesis is that there is a higher prevalence of fibromyalgia syndrome in flight attendants than the prevalence in the general population as well as an even higher prevalence of fibromyalgia for those flight attendants who frequently cross the international date line. Surveys will be sent out to all the flight attendants employed with Northwest Airlines. Questionnaires will include the following: 1) the average mileage/week for the individual flight attendants; 2) any symptoms of generalized myalgia/arthralgia; 3) chronic fatigue; 4) poor sleep or nonrestorative sleep; 5) ever been diagnosed with fibromyalgia or myofascial pain syndrome in the past. The Stanford Health Assessment (HAQ) will also be included, which is the best predictor of work ability. This study will identify flight attendants at risk of fibromyalgia syndrome and increase awareness for early interventions to prevent disability.

An Indirect Health Hazard of Air Travel

Background and Significance:

A quote on the Highway to Health web page reads "And remember: the most dangerous leg of your journey is the ride home from the airport" and further reports that the most common way travelers, particularly international travelers, are injured is in motor vehicle accidents (MVA). This most often is attributed to the perils of driving under unfamiliar road conditions. The web abounds with advice to travelers about the risks of MVAs and methods to reduce this risk. Numerous web sites are also devoted to jet lag, the effects it has on the body, and methods of reducing its impact (e.g. melatonin and bright light therapies). Jet lag occurs when an individual's circadian rhythms are not synchronized (become "desynchronized") with daylight cues at the point of destination and become out of phase with other rhythms. Symptoms include fatigue, insomnia, gastrointestinal disorders, headache, irritability, and decreased performance on attention-related tasks. The period of "restabilization" is dependent upon the number of time zones crossed and can take up to two weeks for full recovery . According to the U.S. National Highway Traffic Safety Administration, MVAs caused by driver fatigue is identified as the primary cause of at least 100,000 accidents and 1,500 fatalities annually. Other studies have reported that drowsy drivers cause about 50% of fatal accidents on highways . In 1996, 16.5 deaths per 100,000 involving MVAs were recorded . The occurrence of flying has risen on an average of 2.0% per year since 1971. The health hazard of MVAs resulting from jet lag caused by air travel is a little studied, yet serious public health threat . Overall there is no definitive evidence of the enormity of the accident risk due to jet lag, either for air accidents, accidents on board, or accidents occurring after the flight . Numerous studies have established that circadian rhythm disruptions caused by shift work and high demand jobs (e.g. medical residents) result in increased accident rates. Little evidence exists that has directly measured the magnitude of the effects jet lag following air travel on the incidence of motor vehicle accidents and consequent morbidity and mortality.


Hypothesis: Sales representatives in positions that require frequent air flight to destinations in different time zones will have a greater incidence of MVAs than Sales Representatives with travel restricted to regional destinations. Study design: This will be a longitudinal study with the aim to prospectively follow participants for five years to record the incidence of MVA's. Data will be collected on age, number of years employed in current position, alcohol consumption habits, sleep patterns, and number of miles driven each month. For regional travelers, data will be collected on the driving conditions associated with each trip (e.g. highway vs. local roads, etc.). For long distance travelers, data will be collected on the frequency of trips, the number of time zones crossed each trip and duration of each trip, as well as a survey of jet lag symptoms following each business trip. This data will be collected each month. Sample population: Five large companies employing sales representatives in positions that require frequent travel to both long distance and regional locations will be asked to participate. A random selection of sales representatives will be enrolled in equal size from two categories of employment:
  1. Sales representatives who routinely travel long distances by way of commercial aircraft involving passage through at least one time zone and
  2. Sales representatives with routine travel involving distances within 300 miles of home.
Sales representatives who are not responsible for their own ground transportation (e.g. driving) will not be included in the study.

Effects of Flying

For some, flying has always been a fear-inducing event. In the post-9/11 world, flying has seemed more fraught with danger. The increased security measures may reassure some that flying is not to be feared, but the sight of armed guards and body searches only heighten the sense of danger for others. The whole process of getting to the airport, checking in and boarding the flight, plus the actual flight itself, continually draw attention to the need for such security measures and the tragedy from which they resulted. While it is now impossible to study people's reactions to flying pre-9/11, we can study current reactions and attempt to determine ways in which the process may be made less anxiety-producing for those individuals.

This study will attempt to determine the effects of flying on the physical and psychological well-being of passengers through interview and monitoring devices. An attempt will also be made to determine coping strategies that may be useful for anxious passengers and to make recommendations which will enable more passengers to travel with less anxiety. Subjects will be randomly selected passengers entering the airport who agree to participate by answering the interview questions pre- and post-flight and wearing the heart and pulse monitor throughout. Data will also be collected regarding any unusual events which occur on the flight and which could affect participants' responses. Data will be analyzed to determine how events and thoughts related to flying influence heart rate and pulse. Results will also be presented on how travel could be made less anxiety-producing.

Perceptions of Airline Safety

College students travel, take risks and are the future airline consumers of tomorrow. Their perceptions of the risks associated with commercial airplane travel as well as their ideas for safety improvements can provide important insight to make airline travel safer. We propose to complete an internet-based survey of college students' attitudes and perceptions about commercial airplane safety. This topic is significant because in a global and mobile society, attitudes and perceptions about airplane safety can cause more Americans to drive automobiles rather than fly which may lead to increase mortality related to automobile accidents. Perceptions of risk are powerful drivers of health behaviors, and college students'attitudes and perceptions can shape an entire generation of travel behaviors.


We propose to administer an internet-based survey of college students' attitudes and perceptions regarding commercial airplane travel and safety. This survey will measure exposure in the previous twelve months, as well as attitudes and behaviors. A random sample of college sophomores and seniors will be selected from 100 universities and colleges from across the county, selected to be representative of American post-secondary institutes. The survey will be introduced initially as an email message with an internet hyperlink directly to the survey. Up to three follow-up email messages will be sent to improve response rate.

The survey will include video game-like graphics and music. It will include simulated scenarios of airplane travel, with prompts for responses at key locations. Music and images will evoke a variety of moods and emotions, from relaxed to excited to adventurous to fearful.

The main hypothesis to be tested is to determine if college students are particularly fearful of flying, what aspects of airplane travel are particularly of concern, and what are their ideas for improved safety.

Prevention of DVT in economy class long air flights: a randomized prevention trial

Introduction and Significance:

Prolonged non-stop flights imply the hazard of thromboses in the deep veins of the leg. Recent reports have linked air travel with deep-vein thrombosis (DVT). Although the magnitude of risk stills a controversial matter, the risk itself is not. Since more than a billion passengers each year travel by air, DVT, once called the economy class syndrome, has become a rather frequent complication among travelers. The true frequency of deep-vein thrombosis during long-haul air travel still is not well known. However, in a recent study published in Lancet, it was concluded based on a relatively small sample size that symptomless DVT might occur in up to 10% of long-haul airline travelers.

As it was concluded in a recent study that the majority of venous thrombo-embolism (VTE) associated with air travel occur in those with identifiable risk factors prior to their flight, certain people are more vulnerable to develop DVT on a flight, including pregnant women, people who are overweight, those whose feet don't reach the floor (because the seat puts more pressure on the backs of their legs), the elderly, smokers and those with coronary artery diseases and certain blood conditions.

Based on the previous data reported increased risk of DVT among certain vulnerable groups, it is necessary as a second step to investigate a possible prevention strategy in these groups, the aim of this study is to test effectiveness of a feasible new seat design (by covering the seat with thin air filled vibrating cushion) in prevention of DVT on a flight


Stress and Air Travel

Commercial air-liners are by far the safest mode of transportation. However, is air travel healthy? There have been many reports that suggest long distance air travel may increase the risk for deep vein thrombosis (DVT), respiratory diseases, and may aggravate other medical conditions. We are interested in the psychological impact of air travel on health. Since the terrorist attacks of September 11, 2001, security measures at airports, specifically passenger gates have increased dramatically. The presence of armed military personnel, scanners with increased sensitivity, and manual searches of personal carry-on items, and ones own person is the norm. We hypothesize that these increased measures may result in increased psychological stress, leading to increased levels of frustration, anxiety, and irritability of air commuters. These effects may in turn result in negative health consequences for individuals who are required to travel by air on a regular basis. Furthermore, this increased stress may influence travelers to select other means of getting to their destinations, which would result in a decrease in air travel and revenue for airlines, and may put travelers at increased risk for accidents due to motor vehicle collisions (the principal alternative to air travel).

To investigate this hypothesis we have formed a collaborative relationship with USAirways and the federal air safety board. We will randomly select 500 travelers from the USAirways ticketing records. Subjects will be asked to complete a simple survey on their experiences before, during, and following their trip. Subjects will be queried about the overall experience of the trip and to rate experiences, and to describe their feelings towards things that may have happened to them from the time the arrived at the airport until they left the airport of their destination. Participants will also be given a wrist monitoring device that will record heart rate, blood pressure, and temperature. Subjects will wear the wrist watch device for 4 hours before the flight to 4 hours following their arrival. Data will be downloaded and analyzed by specially designed software. Subjects will have the opportunity to follow-up with the investigator to review their biochemical and "diary" type data. Data will be analyzed with considerations for frequency of air travel, size and geographic location of airports, age, gender, and SES.

Through this study we hope to develop and understanding of the degree and types of stress experienced psychologically and physiologically by air travelers. The data collected in this investigation will impact our understanding of airport security measures on health and may lead to improvements in these necessary processes such that traveler stress is reduced.

Arrival Time and Jet Lag


In the last twenty years, as air travel has became less expensive, more and more people have incorporated long distance flights into their lifestyle, whether it be for work or pleasure. While this has led people from around the world to be able to collaborate in business and research venues, and allowed people to see parts of the world they never imagined, the long distance flights have not been without their consequences. One such consequence that is often experienced from rapid time zone shifts, which disturbs our circadian rhythms, is "jet lag," a term used to encompass symptoms such as sleepiness, sleeplessness and disturbance in performance. Jet lag can interfere with a person's ability to be their best whether they are traveling for work or to sightsee, making it a concern of the general population. In addition, it may have more critical consequences for professional athletes, who travel the world to compete against their most fierce competitors.

Past research that has studied both the determinants of jet lag and the remedies for decreasing it, has found no major differences in jet lag between business travelers, tourists and high-performance athletes. They have also found no significant relief from benzodiazepine drugs such as triazolam and temazepam, or melatonin, which are all marketed to relieve jet lag symptoms. A few studies have found that age, time of flight arrival, and direction of flight affect jet lag, such that younger adults, those arriving in the evening and those traveling west experience less jet lag, probably because their inner circadian rhythm re-synchronize more quickly.

Since a person can not control their age or the direction they are traveling, this study aims to confirm the sparse evidence that evening arrival time improves jet lag. This study will also examine the sleep patterns of subjects for a full week before travel since this has not been assessed in other studies and may very well influence jet lag recovery. If differences in arrival time or pre-trip sleep patterns affect jet lag, recommendations can be made to travelers who are concerned about their performance after travel.


300 lay persons and 60 professional soccer players who are scheduled for an easterly flight across five time zones will be recruited to participate, such that 120 arrive in the early morning, 120 mid-day and 120 in the evening. A test battery will be administered 7 days before flight time, and at 4 time periods throughout the first full day of arrival and then once a day for the next 7 days. Measures in the test battery will include time of sleep, sleep quality, sleep length, subjective jet lag (one-to-ten simple analogue scale), tympanic temperature, one-, two-, four- and eight-choice reaction time, and strength tests. In addition, as part of the test battery the professional soccer players will rate their level of performance in their specific sport, as well as undergo a 2 day pre and 2 and 4 day post treadmill test.

We hypothesize that those who arrive in the evening report less jet lag and report more quickly that those who arrive in the morning or mid day. We also hypothesize that those who sleep more hours and report better sleep quality before their trip will sleep more hours and report better sleep quality after their arrival and report less jet lag.

Air Recycling Intervention

There is some truth in the saying that if man was supposed to fly, he would have been given wings. Recently there has been much talk about flying and its risks for health. One disturbing fact is that newer jets, as compared to older models, have been designed with less fresh air capacity for passengers in economy class. This controversial step-back in plane technology may present a danger for health of the passengers. Potential problems include a risk of deep vein thrombosis (DVT) and, more often, acute respiratory infections that increases a risk of bioterorism. In-flight air is not humid and fresh enough (humidity falls to 5-10% in long distance flights), air pressure is low, which together causes dehydration and hypoxia and slows the blood flow. The oxygen saturation in our blood falls and our body produces more red blood cells to carry as much oxygen as possible. Moreover, the concentrations of the body chemicals associated with blood clotting are increased in such conditions. Finally, passengers in economy class have less room than normal to move around and boost circulation in their lower extremities. All these factors are responsible for increased risk of DVT. Another dangerous aspect of recycling the air is spreading microorganisms through ventilation system. Already, there has been evidence that the tuberculosis is spreading easily through cabin air, so there is an actual danger of spreading many respiratory germs through ventilation system, especially in economy class where the air is recycled. Thus, having more fresh air in planes would improve health status of the passengers and prevent spreading acute respiratory infections or potential harm of bioterorism act.

Taking into consideration above information and studies that showed that DVT and acute respiratory infections are potential health hazards in flying, we are planning to carry out a pilot clinical trial and compare passengers from planes that followed intervention program and passengers from planes with regular procedures. We will look at the prevalence of deep venous thrombosis, acute respiratory infections, allergies and visual problems to see if our intervention program made a significant difference.

It is estimated that on Boeing 747 aircraft the average cost of running an air package is 80$/hour. If the aircraft is full (about 400 people), it should cost us 20¢ per passenger per hour to have completely fresh air. Intervention program will increase air packs usage on randomly selected flights. Also, passengers on these flights will be given a brochure explaining health risks. The brochure will recommend exercising the day before the flight, in flight exercises with detailed description, and a preventive low dose of aspirin before the flight (with previous consultation with the doctor that we will provide). Passengers will be advised to avoid alcoholic and coffee beverages (diuretically effects), to wear comfortable cloths, and wash hands with soap and water before touching mouth, eyes and nose. Servings of beverages will be doubled.

Intervention program will be inexpensive and easy to implement. Before flying we will collect baseline data and after landing the passengers will be examined. Examination will be repeated after 7 days. We will also establish offices at the Pittsburgh International Airport and at the airports in London and Frankfurt in collaboration with our colleagues abroad. Prior to the flight, passengers who are willing to participate will sign informed consent.

Possible Post-Fly Deaths

We propose to collect a descriptive report of deaths consequent to fly that have occurred in the past year, named "possible post-fly deaths" (PPFD). The purpose of the PPFD report is to clarify whether flying truly exposes at higher risk of death when deaths rates are compared with the general population.

The PPFD report will include all the causes of death that have occurred within 48 hrs from the arrival and have not been caused by any other major accident or injury. The specified cause of death (e.g.: pulmonary embolism, stroke etc.), race, age, gender, number of previous comorbidities and number of known risk factors for cardiovascular diseases (being all the deaths conducible to cardiovascular factors) will be reported, together with origin, duration (hrs) and final destination of the flight. These variables will be used to construct a regression analysis model to answer the question: is flying significantly predicting the death of these subjects? What is the proportion of deaths attributable to flying alone? We will then compare this value to the known predictive value of each single known risk factor (including age, gender, race, number of comorbidities) for each of the causes of deaths observed in the PPFD report. A comparison of the mortality after a flight with the mortality in the general population will also be evaluated.

Air Travel and Health

The issue of the relationship between air travel and health is a major and important topic in contemporary times given recent reports in the news media and suspicion by physicians and the public of increased risk of diseases such as deep venous thrombosis and pulmonary embolism, luekemia and skin cancers and the transmission of infectious diseases such as tuberculosis. Of particular importance also is the issue of safety in air travel given the recent tragic terrorist attacks in New York and Washington DC on September 11, 2001. In addition, the volume of air traffic has been increasing in the past two decades and this is likely to continue as a result of cheaper airfares. Another important issue is the threat of lawsuits against airline companies by victims of air travel related mishaps.

There has been limited research in the area of health risks associated with air travel due primarily to difficulties in the design and conduct of such studies. Most of of the initial studies have been case reports mostly of cases of deep vein thrombosis and pulmonary embolism in individuals after long-haul flights. Recently three case-control studies have examined the risk of thromboembolism associated with long distance travel but the results have been conflicting. Some other studies have tried to evaluate the cancer risk associated with increased exposure to cosmic radiation in air travel but again the results are not conclusive due to difficulties in evaluation of exposure and other confounding variables related to the etiology of these disorders. The argument for an increased risk of infections such as tuberculosis from air travel is more tenuous. Except for few case reports, there appear to be no solid evidence in support of such a hypothesis. Safety issues have become a major issue of concern globally in the recent past and this has been hieghtened by information mismanagement. Available data, however, indicate that the incidence of airplane crash has been falling consistently since the 1970s. In conclusion, although it is biologically plausible to speculate that air travel may be associated with increased risk of certain health-related risks, the extent of the problem appears to be overestimated due to the lack of adequate data on the subject. There is need for properly designed randomized trials to address this important issue in the 21st century to ensure more healthy and safer flights for the global community.

Incidence of Air Rage

To maximize profits, airlines have taken steps that affect the comfort of their customers, the passengers. Namely they have decreased seat size, overbooked flights, and possibly decreased the amount of oxygen in the cabin. The increased discomfort caused by these changes may be leading to an increase in what has become known as "air rage". The potential assault of flight personnel and fellow passengers is a health risk of flying.

I propose a study to measure the incidence of "air rage". All U.S. airlines will be invited to participate. An internet-based coordinating center will be established. Each time an incident occurs, a member of the flight crew will complete an online questionnaire regarding the incident. Data collected will include a description of the nature of the attack and any injury to crew or passengers. If possible, airline records will serve as a source for the amount of oxygen used in the cabin during the flight.

Outcome measurements will be incidence of air rage attacks and the number and types of injuries sustained.

Health and Transport

Traveling by airplane has become more and more common. However, there are only a few researches investigating the relationship between health and flying. The less people know about something, the more dangerous people will think it is. The main idea of this study is to link and compare the health condition during flying to that during other transportations.

A belt like instrument will be designed to monitor both external and internal index for a person while he or she is traveling by airplane, by bus, by car, by train, by bike, by walk and while this person is stay at home and at the office. External indexes include temperature, moisture, pressure, light, cosmic radiation and infectious origins. Internal indexes include blood pressure, heart rate, breath, blood dynamic index, tension of muscles and contraction of digestive organs. 50 men and women between 18 to 75 years old will be recruited for the study. They will be followed up for three to six months until they finish all the above traveling and staying methods. The instrument will collect data continuously for one hour and three times under each of the above conditions. The mean and changing pattern of both internal and external indexes will be compared for each condition.

The hypothesis is: all the health related indexes are the same during flying compared with those during traveling by other transportations.

Bioterrorism and Air Travel


After the recent terrorist attacks in Washington D.C. and New York, a great deal of attention has been given to both flight security and bioterrorism. The first one, obviously because the destructive potential demonstrated and the possibility of killing innocent people aboard airplanes and the second because of the potential mass hazard that could be perpetrated on large populations. Nonetheless, little (or no) attention has been given to a possible combination of these two issues.

Air-borne viruses are the easiest organisms to be spread among a large number of people. At least two viruses deserve special concern due to their potential disastrous consequences. The first one, the smallpox virus, "eradicated" form our environment, but still preserved, somewhere by someone. The other one is the influenza virus, our old acquaintance not really lethal at this point, but I'm sure that the 1918 pandemic showed us its potential, and nobody knows if a genetic-modified '1918-like' strain could be developed for bioterrorist purposes.

A very efficient way to widely spread smallpox or influenza viruses in the US (or anywhere else in the world) would be the use of airplanes. In a coordinated fashion it would be easy for terrorists to get inside airplanes going to different US cities, infected with the either virus, in a early phase of the disease, when it is highly contagious and the symptoms have not yet been fully developed.

Given this situation it is imperative that some kind of early detection of this threat be developed before a disaster of unprecedented magnitude take place among our population. The purpose of this project id to develop a sputum-based rapid diagnosis test for smallpox and influenza viruses to be used in airports around the country - or perhaps the world.


The structures of these viruses are very different. The smallpox virus (Poxviridae family) is a double-stranded DNA virus, while the influenza virus (Orthomixoviridae family) is a single-stranded RNA virus. Because of that there should be developed two different media to diagnose each of the viruses, even though the idea for both is the same: to develop a color-sensitive medium to detect DNA or RNA-specific fragments of the virus genome from a simple sputum sample. The first phase of the project is to develop the media in vitro and subsequently test it with animal models and then with the public itself. For this last phase, we cannot use real cases of smallpox, only if there's a real epidemic, but we can use cases of regular strains of influenza virus.

DVT survey

It is a well-known fact that airplane passengers spend most of the entire flight in a sitting position. Except for first class passengers, there is a limited amount of leg room space. Since airplane passengers are now expected to arrive at the airport at least 2-3 hours prior to their scheduled departure, travelers are more likely to develop circulation problems such as deep vein thrombosis (DVT) as a result of the additional sitting time.

In the past, there has been much debate about the risk of developing DVT, especially during lengthy flights. Although data have inconsistent regarding the risk of DVT and flying, the additional time passengers spend in the airports and during flights may increase the occurrence of this serious health problem.

To test the hypothesis that airplane travel increases the risk of developing DVT, airline passengers scheduled on flights longer than 2.5 hours in duration will be asked to complete a 10-item questionnaire at the conclusion of the flight. Passengers will be randomly selected as they exit the plane. The 10-item questionnaire will include demographic information, general health, frequency of airline travel, feelings of discomfort, and predisposing conditions that may increase the risk of DVT such as previous injury to the leg, recent surgery, poor circulation, pregnancy, infections liver disease and some cancers.

The questionnaire will be administered by airline staff. Participants will be asked for contact information to facilitate a brief follow-up self-administered interview (postcard format) 4 weeks after to the baseline interview. Follow-up questions will inquire about the onset of any health conditions after airline travel. Participants who do not return the completed follow-up postcard will be contacted again by mail and then by telephone, if possible, and interviewed via telephone. The interviewing phase will be conducted for approximately six months.

Air Quality in Planes


Air quality in the passenger cabins of commercial airplanes has been an ongoing concern for many years. In 1986, The National Research Council of the National Academies published "The Airliner Cabin Environment: Air Quality and Safety". As a result the Federal Aviation Administration (FAA) tightened its air quality standards that included elimination of smoking in all domestic flights, requiring more fresh air in the cabin, lowering the maximum level of carbon dioxide, and developing better record keeping systems. As a result of these changes, research shows that air quality has improved significantly in today's airplanes. However, the FAA airworthiness standards in Part 25, Subpart D, Design and Construction Specifics, includes current standards for certifying larger passenger airplanes that are purchased by the airlines. The section only specifies standards for new transport category airplanes and these may not be the standards that were applied when older airplanes were certified. The standards were not developed to retrospectively apply to older airplanes and therefore the air quality may not be as good in older airplanes that are still in use today. A comparison of air quality between airplanes constructed prior to and after 1986 may lead to further air quality improvement.


The following null hypothesis will be tested: there is no difference in the quality of commercial airplane cabin air between airplanes built prior to and after 1986. Quality of air is defined as per the FAA's airplane cabin air quality standards. Air sample analysis will be done for airplanes built before and after 1986. The data will then be analyzed and recommendations will be made if appropriate.

Depression and Circadian Rhythm Disruption in Flight Attendants

Hypothesis: There is no association between the disruption of Circadian rhythms and the incidence of depression in flight attendants on long haul international flights when compared to those on short domestic flights.

Within the medical literature it is an accepted fact that consistent disruptions in the Circadian rhythm can lead to depression and psychological stress. Flight attendants on long-haul flights (transatlantic or equatorial or polar (North-South/East-West)) may be at increased risks for depression when compared to flight attendants on domestic (30' to 6 hr) flights. Severe depression has a profound impact on an individual's ability to function, i.e. day-to-day activities and can be detrimental to job performance.

Methods: Flight attendants (FAs) currently employed by American Airlines and living in the Dallas-Forth Worth region were eligible for this study. Dallas-Forth Worth is the hub for American Airlines and the majority of its FAs reside in this region. FAs with long-haul/domestic assignments will be recruited using contact information from the airline's Human Resources Departments and the American Airline Flight Attendants' Union. After sending an introductory letter, flight attendants will be recruited (contacted and consented) and interviewed at their homes by Registered Nurses with specialties in mental health. Demographic data, depression and stress inventories will be administered. Depression will be measured using the Beck's Depression Inventory and the Hamilton Rating Scale for Depression. A sub-sample of interviews will be taped (with the consent of the study participant) and evaluated by the team psychologist in order to monitor the reliability of interviewer rating. Employment histories will be obtained from the airline's Human Resources Department, i.e, number of flights completed by week, month and year, number of international vs domestic flights, types of airplanes that crew members have flown on, applications for sick leave and reasons for requesting sick leave etc. The airline's health insurance carriers will be queried for data on claims for doctor's visits, both for primary and specialist care. The outcome variable will be the number of individuals with receiving scores that indicate some form of depression. Studentized t- tests will be used to compare the scores obtained for FAs on long-haul and domestic flights.

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