vagabond

Note: There are quite a number of studies out there looking at the relationship between exposure to cosmic radiation and incidents of cancer specific to airline pilots. Below are abstracts of just some of them. For the sake of space and expediency, I have not included the authors' names, but note that these studies, at least, were conducted in Europe.

Cosmic radiation increases the risk of nuclear cataract in airline pilots: a population-based case-control study.

Department of Preventive Medicine, University of Iceland, Neshagi 16, 107 Reykjavik, Iceland. [email protected]

BACKGROUND: Aviation involves exposure to ionizing radiation of cosmic origin. The association between lesions of the ocular lens and ionizing radiation is well-known.
OBJECTIVE: To investigate whether employment as a commercial airline pilot and the resulting exposure to cosmic radiation is associated with lens opacification.
METHODS: This is a population-based case-control study of 445 men. Lens opacification was classified into 4 types using the World Health Organization simplified grading system. These 4 types, serving as cases, included 71 persons with nuclear cataracts, 102 with cortical lens opacification, 69 with central optical zone involvement, and 32 with posterior subcapsular lens opacification. Control subjects are those with a different type of lens opacification or without lens opacification. Exposure was assessed based on employment time as pilots, annual number of hours flown on each aircraft type, time tables, flight profiles, and individual cumulative radiation doses (in millisieverts) calculated by a software program. Odds ratios were calculated using logistic regression.
RESULTS: The odds ratio for nuclear cataract risk among cases and controls was 3.02 (95% confidence interval, 1.44-6.35) for pilots compared with nonpilots, adjusted for age, smoking status, and sunbathing habits. The odds ratio for nuclear cataract associated with estimation of cumulative radiation dose (in millisieverts) to the age of 40 years was 1.06 (95% confidence interval, 1.02-1.10), adjusted for age, smoking status, and sunbathing habits. CONCLUSION: The association between the cosmic radiation exposure of pilots and the risk of nuclear cataracts, adjusted for age, smoking status, and sunbathing habits, indicates that cosmic radiation may be a causative factor in nuclear cataracts among commercial airline pilots.

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Cosmic radiation and cancer mortality among airline pilots: results from a European cohort study (ESCAPE)

Abstract: Cosmic radiation is an occupational risk factor for commercial aircrews. In this large European cohort study (ESCAPE) its association with cancer mortality was investigated on the basis of individual effective dose estimates for 19,184 male pilots. Mean annual doses were in the range of 2–5 mSv and cumulative lifetime doses did not exceed 80 mSv. All-cause and all-cancer mortality was low for all exposure categories. A significant negative risk trend for all-cause mortality was seen with increasing dose. Neither external and internal comparisons nor nested case-control analyses showed any substantially increased risks for cancer mortality due to ionizing radiation. However, the number of deaths for specific types of cancer was low and the confidence intervals of the risk estimates were rather wide. Difficulties in interpreting mortality risk estimates for time-dependent exposures are discussed.

Abbreviations CI confidence interval - CLL chronic lymphatic leukemia - RRC radiation-related cancers - NRRC non-radiation-related cancers - RR relative risk - SMR standardized mortality ratio

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Incidence of cancer among Nordic airline pilots over five decades: occupational cohort study

Objective: To assess the incidence of cancer among male airline pilots in the Nordic countries, with special reference to risk related to cosmic radiation.
Design: Retrospective cohort study, with follow up of cancer incidence through the national cancer registries.
Setting: Denmark, Finland, Iceland, Norway, and Sweden.
Participants: 10 032 male airline pilots, with an average follow up of 17 years.
Main outcome measures: Standardised incidence ratios, with expected numbers based on national cancer incidence rates; dose-response analysis using Poisson regression.
Results: 466 cases of cancer were diagnosed compared with 456 expected. The only significantly increased standardised incidence ratios were for skin cancer: melanoma 2.3 (95% confidence interval 1.7 to 3.0), non-melanoma 2.1 (1.7 to 2.8), basal cell carcinoma 2.5 (1.9 to 3.2). The relative risk of skin cancers increased with the estimated radiation dose. The relative risk of prostate cancer increased with increasing number of flight hours in long distance aircraft.
Conclusions: This study does not indicate a marked increase in cancer risk attributable to cosmic radiation, although some influence of cosmic radiation on skin cancer cannot be entirely excluded. The suggestion of an association between number of long distance flights (possibly related to circadian hormonal disturbances) and prostate cancer needs to be confirmed.

vagabond

Inflight Occupational Exposures to Cosmic Radiation and Magnetic Fields
Reprinted with permission from Air Line Pilot, January 2000, page 30
by Capt. Gary C. Butler (Canadian), Ph.D.
Director, ALPA Aeromedical In-Flight Occupational Exposure Research
Scientists have known since 1907 that radiation originating outside the earth’s atmosphere causes increasing effects as altitude above the ground increases. Modern scientists generally believe that stellar flares, stellar coronal mass ejections, supernova explosions, pulsar acceleration, and galactic nuclei explosions produce and accelerate this radiation, called cosmic radiation.

Radiation is transmitted through space in the form of photons or subatomic particles. Cosmic radiation is a mixture of various types of “ionizing radiation”—a term used if the photons or particles produce, in the material irradiated, one or more ions, or electrically charged atoms or group of atoms. Ionization is the primary process by which radiation exposure affects biological organisms.

Flight crews, while flying, are exposed to amounts of cosmic radiation that are greater than persons on the ground receive from both cosmic and terrestrial radiation. Sources of terrestrial radiation that contribute to whole-body exposure include potassium-40 and the radioactive decay products of uranium-238 and thorium-232. The three are found in soil and rock near Earth’s surface.

Galactic radiation
At airliner flight altitudes, high-energy subatomic particles—primarily protons (95 percent), alpha particles (3.5 percent), and heavier nuclei—mostly from outside the solar system are colliding with and disrupting atoms of nitrogen, oxygen, and other atmospheric gases. These collisions produce photons and additional subatomic particles, which are referred to as galactic cosmic radiation. The number of galactic radiation particles entering the atmosphere and, as a consequence, the amount of radiation at airliner flight altitudes varies inversely with an approximate 11-year cycle of rise and fall of solar activity. Magnetic fields associated with low-energy subatomic particles (solar wind) that the sun continuously emits deflect lower-energy galactic particles that would otherwise enter the atmosphere; this causes the variation in the amount of galactic radiation. The solar wind particles are in themselves too low in energy to affect the amount of radiation at flight altitudes.

Variation with latitude and altitude
At any given cruise altitude, the galactic radiation dose-rate increases with distance north or south of the equator until it plateaus at high latitudes. In the northern hemisphere, at a constant altitude, the galactic radiation level shows little or no increase above 50 degrees latitude in North America and 60 degrees in Europe and Asia. Amounts of radiation above the Poles at airliner cruise altitudes are twice those above the equator at the same altitudes. Earth’s atmosphere provides significant shielding from cosmic radiation. The lower the altitude, the thicker the atmospheric layer and, therefore, the greater the protection.

Solar flares
A solar flare is an intense magnetic disturbance on the sun, resulting in an explosive emission of various kinds of radiation. During some solar flares, the number and energies of particles emitted from the sun may temporarily become high enough to significantly increase the amount of ionizing radiation at flight altitudes, particularly over the polar regions.

Until very recently, solar flares that would emit particles could not be predicted reliably nor could one predict how far the radiation would reach, even after the event had occurred. However, NASA, using the Japanese Yohkoh spacecraft, discovered that S-shaped patterns often appear on the surface of the sun before these violent solar eruptions. NASA’s data indicate a strong correlation between an S-shaped pattern on the sun and the likelihood that an eruption will occur in that region within days.

At altitude, the radiation resulting from solar flares is produced in the same way as galactic cosmic radiation is produced. The particles from the sun, as well as the photons and particles they produce in the atmosphere, are referred to collectively as solar cosmic radiation. Between 1956 and 1991, inclusive, approximately 6 solar particle events occurred during which the radiation at 41,000 feet above the polar regions probably rose to more than 100 microsieverts per hour. The normal radiation level at these locations is approximately 12 microsieverts per hour.

When considering health effects of ionizing radiation, the amount of radiation that an individual receives is expressed in terms of sieverts. The sievert is a measure of the biological harm that ionizing radiation may cause and is the current international unit for this measurement. The sievert replaces the rem.
1 sievert=100 rem
1 sievert=1,000 millisieverts (mSv)
1 millisievert=1,000 microsieverts (mSv)

Effective dose: When irradiation of the body is not uniform, the effective dose is an approximately uniform whole-body dose that would result in the same risk of cancer, hereditary effects, and length of life lost as the nonuniform exposure. When irradiation of the body is approximately uniform, the dose and effective dose are the same.

Radiation exposure and recommended limits
The FAA (Dr. Wallace Friedberg, Civil Aeromedical Institute) has estimated the amount of galactic radiation that aircrew members receive on a wide variety of routes to, from, and within the contiguous United States. Cumulative dosage, of course, will vary depending on altitude, latitude, and duration of flight on the route flown.

At the present stage of the solar cycle, the galactic dose ranges from 0.023 to 0.80 millisievert per 100 block hours. For example, based on 0.60 mSv per 100 block hours (the mean for a flight between New York City and Athens, Greece), a pilot flying 700 block hours per year would receive an annual occupational exposure of 4.2 mSv. In contrast, a pilot flying 700 block hours on a Chicago-to-San Francisco route (0.41 mSv/100 block hours) would receive an annual dose of approximately 2.8 mSv.

Typically, cosmic radiation exposure for airline pilots in North America ranges from 3 to 5 millisieverts annually. These values are considerably lower than the occupational limit of 20 millisieverts per year (5-year average) that the International Commission on Radiological Protection (ICRP) recommends for a nonpregnant adult.

Considerations during pregnancy
Some recommendations concerning exposure apply only to pregnant women. The ICRP recommends that once a woman learns she is pregnant, her occupational exposure to ionizing radiation should not exceed 1 millisievert for the remainder of the pregnancy. Further, the exposure of the unborn child should not exceed 0.5 millisievert in any month (excluding medical exposures), once a pregnancy becomes known.

For radiation protection purposes, the unborn child is assumed to receive the same dose of cosmic radiation as the mother; but on some flights, the galactic radiation that an unborn child receives may exceed the recommended limits. For example, consider two flights: a long (9.5 hours) New York-to-Athens flight and a short (0.5 hour), low-altitude flight from Houston to Austin, Tex. The effective dose from the long-haul flight is approximately 64 microsieverts (mSv), whereas the effective dose from Houston to Austin is only about 0.14 microsieverts.

The long-haul pregnant pilot will clearly exceed the 1 mSv limit (64 mSv equals 0.60 mSv/100 block hours/month). Working on short, low-altitude flights, or alternately, being assigned to a ground position for the remainder of the pregnancy, could reduce a pregnant pilot’s exposure to radiation.

All flightcrew members can calculate their cosmic radiation dose using the FAA computer program CARI-5E. A free download is available through the Internet at http://www.cami.jccbi.gov/research/610/600radio.html

Health concerns
The health concerns about aircrew members’ exposure to cosmic radiation are increased risk of cancer, genetic defects that can be passed on to future generations, and harm to an unborn child. Death from cancer is the primary health risk associated with occupational exposure to ionizing radiation; that is, damage to genetic material (DNA) in the cell is thought to be the mechanism that underlies the potential risk of increased cancer.

The risk to aircrew members of eventually dying of cancer as a result of exposure to galactic radiation during a career of flying, compared to the risk to the general population, is slightly higher, as are the risks of causing genetic defects and of harming an unborn child.

Research projects investigating health effects in flight crews caused by cosmic radiation exposure are relatively few. Generally, while these studies have reported some additional cancers, their results are far from definitive.

At present, although one cannot exclude the possibility of harm from exposure to cosmic radiation at the doses likely to be received during a career of flying, establishing that an abnormality or disease in a particular individual resulted solely from radiation exposure would be impossible. Cosmic radiation is but one of the environmental stressors that affect pilot health.

Among the physiological challenges to the long-term health of an airline pilot are circadian dysrhythmia, reduced atmospheric pressure, mild hypoxia, low humidity, noise, vibration, cosmic radiation, and magnetic fields. In particular, exposure to cosmic radiation and its potential for causing cancer have recently received considerable attention.

Given the complexity of an airline pilot’s environment and the possibility that two or more of the stressors might work together to cause more harm than each would separately, comprehensive research into both cosmic radiation and magnetic field exposures in airline pilots is needed now. However, studies of how radiation affects airline flight crews are confronted with several challenges.

First, one must deal with the probability that both ionizing and nonionizing radiation (magnetic fields) enhance the harm inherent in several other occupational exposures. Second, as health effects among flightcrew members are small, detecting them may be difficult. Third, access to a large population of airline pilots has been traditionally difficult to secure. Fourth, actual measurement of cosmic radiation doses is not yet on solid ground, which may result in an underestimation of doses. And fifth, any discussion of potential ionizing radiation risk and/or cancer incidence assessment must include biological markers of past cosmic radiation exposure.

Within this context, ALPA (Project Director: Dr. Gary C. Butler), in conjunction with the Medical University of South Carolina (Department of Biometry and Epidemiology, Dr. J. Nicholas and Dr. Dan Lackland), has begun an extensive research program to study these occupational exposures. Dr. Don Hudson (ALPA’s aeromedical advisor) and Capt. Allan Campbell (Delta pilots’ Master Executive Council Aeromedical Committee chairman) are also involved in this project. The FAA’s Civil Aeromedical Institute (Dr. Friedberg) is also involved in conducting this research.

The research program is now making ground-based calculations, quantifying magnetic field exposure on the flight deck, and undertaking an epidemiological survey and exposure assessment. The epidemiological study has three primary objectives:

· Assess cancer incidence in a large group of U.S. and Canadian
airline pilots, through a health survey sent to approximately 9,000
active and 1,000 retired Delta Air Lines pilots and to 1,300 active
and 350 retired Canadian Airlines International pilots.

· Construct an extensive database on flight dosage rates, based on
a flight history survey.

· Analyze the relationship between exposure to cosmic radiation
and the presence of specific medical conditions.

The results of this study (available in early winter 2000) should provide initial comprehensive data on cancer risk assessment and ionizing radiation.

The next phase of this research is to investigate whether chronic low-dose radiation exposure can be detected in biological markers; that is, has ionizing radiation induced any chromosomal changes in circulating white blood cells? The primary objective is to develop a better understanding of the potential biological hazards in airline pilots chronically exposed to low radiation doses.

vagabond

Part II of ALPA study:

This is the first North American study to investigate biological markers that may result from radiation exposure in this professional group. The results of this project, begun in June 1999, will provide information on the degree to which cosmic radiation exposure affects biological markers in pilots. In this phase of the research, in addition to the Medical University of South Carolina, the Fred Hutchinson Cancer Research Center (Dr. Scott Davis), University of Washington, Seattle, will be involved.

Magnetic fields
Magnetic fields, one of the elementary fields of nature, are caused by electric charges and their motion. Either a permanent magnet or a steady flow of electric current can produce a static electric field. A steady flow of electric current produces a direct-current (dc) magnetic field, and electric currents alternating in time produce alternating-current (ac) magnetic fields. Electric power that operates devices in the workplace or at home produces magnetic fields. Electric charges moving to produce a current create magnetic fields.

Magnetic fields are characterized by their frequency (expressed in hertz) and strength (see “magnetic field strength” in the glossary). They are generally described in units of microtesla (1mT=0.000001T) or milligauss (1mG=0.1mT). For example, the earth’s magnetic field is a static field of approximately 50mT (0.5G). Magnetic fields, unlike electric fields, can pass through the human body and induce electric currents.

The presence of humans and animals does not affect the extremely low frequency magnetic field (ELF). Therefore, the measured field represents the actual exposure field.

Magnetic fields are known to interact with biological systems. Particularly at low field strengths, magnetic fields’ biological effects on cell metabolism and growth, gene expression, hormones, and promotion of tumors have been reported. Some magnetic field effects, such as the ability to stimulate tissue and bone growth, have been found to be beneficial; other effects might be harmful.
Biological effects
Researchers have suggested that magnetic fields suppress pineal body function and production of the pineal body’s principal hormone, melatonin, thereby increasing the risk of developing certain cancers, particularly breast cancer. Indeed, female airline flight attendants in both Finland and Denmark have been documented to have an increased incidence of breast cancer, which researchers have suggested is due to their simultaneous exposure to both magnetic fields and cosmic radiation.

Melatonin generally suppresses other endocrine glands. Reduced concentrations of melatonin may result in the pituitary releasing increased prolactin and the gonads releasing increased estrogen and testosterone. An increase in the amount of circulating estrogen might, in turn, stimulate proliferation of breast tissue. In addition, melatonin has been demonstrated to directly inhibit tumor growth in estrogen-responsive MCF-7 human breast cancer cells in culture.

The magnetic field strength associated with a reduction in melatonin has been reported to be as low as 0.3 to 1 microtesla (mT) at 50 hertz (Hz) in rats, and the tumor-growth–inhibiting action of melatonin on human breast cancer cells in culture has been reported to be blocked at a threshold magnetic field level of 0.2 to 1.2mT. Recent studies have documented the strength of magnetic fields in aircraft cabins during flight—the magnetic field may vary from 1 to 10mT.

A more recent paper concluded that the magnetic field exposure appears to be characterized by frequencies between 100 and 800 hertz and varies in strength depending on the location within the aircraft, and aircraft type. That is, based on limited measurements, maximum field strength varied from 0.2 to 0.6mT in economy class, to 1.2mT in first class, to 1.7mT in the first class galley. Based on these results, researchers have suggested that magnetic field exposure on the flight deck may be significantly higher.

These observations provide the incentive to further explore magnetic field exposure on the flight deck. Other studies on occupational magnetic field exposure have been inconsistent, but one study in office workers suggests that melatonin may be reduced during work with video display units. At 30 centimeters from the screen of a video display unit, the reported magnetic field level is less than or equal to 0.25 to 0.7mT (compared to approximately 0.1mT in the typical home environment).

Suppression of pineal function has been implicated in causing prostate cancer and melanoma, both of which have been found among airline flight crews. Significantly increased incidence of prostate cancer has been found among Air Canada and British Airways pilots. When compared with a group of nonflying U.S. Air Force (USAF) officers, male USAF pilots were found to have more genital cancer and testicular cancer. Unlike breast tissue, the prostate appears to have a low sensitivity to ionizing radiation and resultant cancer.

In malignant melanoma, or skin cancer, the combined effect of solar radiation and reduced melatonin may be important. In a proportional mortality ratio study, British Airways pilots were found to have a 6 times greater risk of developing melanoma.
An increased risk of developing malignant melanoma was also found in an incidence study among USAF pilots.

Because flight crews may work at night, the effect of light, particularly light at night, on melatonin production must be considered. Light as perceived by the retina suppresses melatonin production, and therefore, circulating concentrations of melatonin are typically low in the day and high at night. However, the greater amount of melatonin in the body at night does not depend on being asleep or awake; if the light level is dim, a person will maintain a normal rhythm even if he or she is awake all night. Because aircraft lights are typically dimmed during night flight, any reduced nighttime melatonin production among flight crews may be related primarily to magnetic fields.

Electromagnetic fields (EMF) may work together with other factors in the cancer process. Researchers have proposed that an EMF-induced increase in the body of chemicals called “free radicals” may inhibit a cell’s ability to protect itself against an attack by such antioxidants as a toxic chemical or ionizing radiation. The free-radical increase may result from EMF disrupting calcium balance or reducing melatonin. Recent studies have shown melatonin to be a potent hydroxyl radical scavenger, preventing cancer-causing damage to nuclear DNA. Thus, reduction in melatonin might increase the likelihood of developing cancer and suffering DNA damage. In addition, magnetic field exposure might induce or prolong the half-life of free radicals, which melatonin is known to scavenge.

Several studies support the possibility that magnetic fields may inhibit a cell’s ability to protect itself from ionizing radiation. Human lymphocytes exposed to both ionizing radiation and 60 Hz magnetic fields have demonstrated a greater number of chromosomal aberrations than have been observed after exposure to ionizing radiation alone. T-lymphocytes previously exposed to strong magnetic fields have been found to be more radiosensitive than control cells, and exposure to magnetic fields has been found to induce greater ionizing radiation effects in the cultured mammalian cell line FM3A.

Research
The primary purpose of the ALPA co-sponsored research is to help pilots develop a better understanding of their exposure to magnetic fields on the flight deck.

The initial phase of this research, which was recently completed, involved quantifying magnetic field exposure of airline pilots during domestic and international flying on four different aircraft types (B-737-200, A320, B-767-300ER, and B-747/400) using an EMDEX II meter. Results will be published in an upcoming issue of Air Line Pilot.
The next phase of this research will involve more comprehensive measurements including using a multi-wave meter to capture transients of the magnetic field.

Glossary
• Cancer is a malignant tumor of potentially unlimited growth, capable of invading surrounding tissue or spreading to other parts of the body by metastasis.
• Carcinogen is any cancer-producing substance.
• Chromosome—DNA of each cell is packed into chromosomes within the cell nucleus. Each human somatic cell contains 23 pairs of chromosomes, or 46 total chromosomes.
• Endocrine glands secrete hormones into the circulatory system and influence tissues that are separated by some distance from the endocrine glands. Hormones act on specific tissues and influence the tissues’ activity in a specific fashion.
• ELF—extremely low frequency—is usually associated with frequencies in the order of 3 Hz to 3 kHz.
• Epidemiology is the study of the prevalence and spread of disease in the community. The two main types of epidemiological studies of chronic disease are cohort (follow-up) or case control (retrospective).
• Gauss is the centimeter-gram-second (cgs) unit of magnetic field density; 1 G=10–4 tesla (T) (tesla is the SI unit of magnetic field density); 1mG=0.1mT.
• Free radicals—In chemistry, a radical is group of elements or atoms usually passing intact from one compound to another, but usually incapable of prolonged existence in a free state. Free radicals are radicals in a transient uncombined state, an atom or group of atoms carrying an unpaired electron and no charge: e.g., hydroxyl and methyl.
• Hertz (Hz) is the SI unit of frequency. 1 Hz = sec–1
• Ionizing radiation is radiation sufficiently energetic to eject electrons from an atom. Ionizing radiation includes x and gamma radiation, electron (beta radiation), alpha particles (helium nuclei), and heavier charged atomic nuclei.
• Melatonin, a hormone that the pineal body secretes in the brain’s epithalamus, exerts a generally suppressive action on other endocrine glands. Changes in the amount of daylight during each day regulate pineal secretion; that is, increased daylight causes, in the retina of the eye, impulses that are propagated to the brain, and decreased pineal secretions result. In the dark, pineal secretion increases.
• Metastasis, in cancer, is the appearance of new-growth tumors (neoplasms) in parts of the body remote from the primary tumor; metastasis results from dissemination of tumor cells by the lymphatics or blood vessels, or through serous cavities or subarachnoid or other spaces.
• Oncogenes are genes that carry the potential for cancer.
• Pineal body is located in the epithalamus of the brain and functions as an endocrine gland that secretes hormones that act on the hypothalamus or the gonads to inhibit reproductive functions. The pineal body has also been shown to affect the activity of the adrenal glands, the thyroid, and the pancreas, and may be involved in the sleep-wake cycle.
• SI, Systeme International, is an internationally adopted system of units, for example: meter, kilogram, and coulomb.
• Tesla (T)—Magnetic fields are expressed in tesla (T) or gauss (G), where 1T=104G. Because the range of magnetic fields encountered are quite small, the fields are generally described in units of microtesla (1mT=0.000001T) or milligauss (1mG= 0.001G). For example, Earth’s magnetic field is a static field of about 50mT (0.5G), and a current of 50 amperes in a straight wire produces a magnetic field of 100mT at a distance of 10 centimeters. Tesla is the SI unit of magnetic field density.
• White blood cells (lymphocyte), formed in lymphoid tissue throughout the body, produce antibodies and other chemicals that are responsible for destroying microorganisms; white blood cells are also involved in allergic reactions, graft rejection, tumor control, and immune system regulation.

rickair7777

I have previous professional experience in occupational radiation dosimetry. The types and amounts of radiation (increased cosmic and solar) which airline pilots are exposed to is statistically almost insignificant. After I got into flying I got together with a leading health-physicst and actually ran all the numbers, and it compared pretty favorably with other occupations.

The correlation between sunlight exposure and corneal problems is obvious and longstanding. People who spend a lot of time outdoors tend to have have cataracts and other eye problems. I suspect that pilots are prone to these because:
1) Historically, we have had a lot of time off.
2) As a group we tend to be active outdoors types, not couch-potatoes.

Remember the studies cited above occured over years or decades ago, so 1) and 2) were even more true back in golden days of the airline biz. Also, the older generations didn't necessarily KNOW that it was bad to exposure your eyes to a lot of sunlight, and they may not have had UVB sunglasses.

vagabond

Yes, I agree with you, rickair. The posted abstracts are just a small sample of the studies. A general reading of these and others reveal that the authors themselves concede that the effects of radiation is insignificant as compared to the general population. There are lots of interesting studies looking at skin cancers and pregnant pilots, too.

Do you happen to know of studies on longevity of airline pilots, particularly those who fly at night and/or international (crossing many time zones)?

HSLD

For those interested, we have a radiation profile tool available on the site that allows you to get a good estimate of radiation exposure per segment. The database is about a month behind (blame the FAA, not us!) although it does account for solar flare activity, etc.

http://airlinepilotcentral.com/frame...n_profile.html

Anyone else get solar flare alerts on their flight plans when activity is above S2 levels?

rickair7777

No, but I do suspect from personal experience that circadian rythm dispruptions are the REAL occupation threat to pilot health. Jet-A fumes may not be too healthy either.