Cancer incidence among Norwegian airline cabin attendants

BACKGROUND: Cabin crews are exposed to cosmic radiation at work and this may increase their incidence of radiation-induced cancers. Former studies indicate an increased risk of breast cancer. METHODS: A retrospective cohort study was performed. The cohort was established from the files of the Civil Aviation Administration and included people with a valid licence as a cabin attendant between 1950 and 1994. The cohort was linked to the Cancer Registry of Norway. Observed number of cases was compared with expected, based on national rates. Breast cancer incidence was analysed, adjusting for individual fertility variables. RESULTS: A group of 3693 cabin attendants were followed over 72 804 person-years. Among the women, 38 cases of breast cancer were observed (standardized incidence ratio (SIR) = 1.1, 95% CI : 0.8-1.5). Among men excess risks were found for cancers in the upper respiratory and gastric tract (SIR = 6.0, 95% CI : 2.7-11.4) and cancer of the liver (two cases, SIR = 10.8, 95% CI : 1.3-39.2). For both sexes elevated risks were found for malignant melanoma and non-melanoma skin cancer; for men these were SIR = 2.9 (95% CI : 1.1-6.4) and SIR = 9.9 (95% CI : 4.5-18.8) respectively, while for women these were SIR = 1.7 (95% CI : 1.0-2.7) and SIR = 2.9 (95% CI : 1.0-6.9) respectively. For no cancer site was a significant decreased risk found. CONCLUSIONS: An increased risk of radiation-induced cancers was not observed. The excess risks of some other cancers are more probably explained by factors related to lifestyle.     

Mortality from cancer and other causes among airline cabin attendants in Germany, 1960-1997

Airline cabin attendants are exposed to several potential occupational hazards, including cosmic radiation. Little is known about the mortality pattern and cancer risk of these persons. The authors conducted a historical cohort study among cabin attendants who had been employed by two German airlines in 1953 or later. Mortality follow-up was completed through December 31, 1997. The authors computed standardized mortality ratios (SMRs) for specific causes of death using German population rates. The effect of duration of employment was evaluated with Poisson regression. The cohort included 16,014 women and 4,537 men (approximately 250,000 person-years of follow-up). Among women, the total number of deaths (n = 141) was lower than expected (SMR = 0.79, 95% confidence interval (CI): 0.67, 0.94). The SMR for all cancers (n = 44) was 0.79 (95% CI: 0.54, 1.17), and the SMR for breast cancer (n = 19) was 1.28 (95% CI: 0.72, 2.20). The SMR did not increase with duration of employment. Among men, 170 deaths were observed (SMR = 1.10, 95% CI: 0.94, 1.28). The SMR for all cancers (n = 21) was 0.71 (95% CI: 0.41, 1.18). The authors found a high number of deaths from acquired immunodeficiency syndrome (SMR = 40; 95% CI: 28.9, 55.8) and from aircraft accidents among the men. In this cohort, ionizing radiation probably contributed less to the small excess in breast cancer mortality than reproductive risk factors. Occupational causes seem not to contribute strongly to the mortality of airline cabin attendants.     

Cancer incidence among Norwegian airline pilots

OBJECTIVES: In this retrospective cohort study, the cancer incidence of commercial pilots was studied to determine whether exposure at work has any influence on the incidence of cancer. METHODS: The cohort was established from the files of the Civil Aviation Administration and included people who had valid licenses as commercial pilots between 1946 and 1994. Basic data about their flight careers were recorded, and exposure to cosmic radiation was estimated. The cohort was linked to the Cancer Register of Norway. The observed number of cases was compared with that expected based on national rates. RESULTS: A group of 3701 male pilots was followed over 70 560 person-years. There were 200 cases of cancer versus 188.8 expected, with a standardized incidence ratio (SIR) of 1.06 and a 95% confidence interval (95% CI) of 0.92-1.22. No significant decreased risk was found for any cancer site. Excess risks were found for malignant melanoma (22 cases SIR 1.8, 95% CI 1.1-2.7) and nonmelanoma skin cancer (14 cases, SIR 2.4, 95% CI 1.3-4.0). For malignant melanoma, there was a significant trend for the SIR by cumulative dose. CONCLUSIONS: For most cancer sites, the incidence among pilots did not deviate from that of the general population and could not be related to block hours of flight time or dose. It seems more likely that the excess risks of malignant melanoma and skin cancer are explained by factors related to life-style rather than by conditions at work.     

Incidence of cancer among commercial airline pilots

OBJECTIVES—To describe the cancer pattern in a cohort of commercial pilots by follow up through the Icelandic Cancer Registry.
METHODS—This is a retrospective cohort study of 458 pilots with emphasis on subcohort working for an airline operating on international routes. A computerised file of the cohort was record linked to the Cancer Registry by making use of personal identification numbers. Expected numbers of cancer cases were calculated on the basis of number of person-years and incidences of cancer at specific sites for men provided by the Cancer Registry. Numbers of separate analyses were made according to different exposure variables.
RESULTS—The standardised incidence ratio (SIR) for all cancers was 0.97 (95% confidence interval (95% CI) 0.62 to 1.46) in the total cohort and 1.16 (95% CI 0.70 to 1.81) among those operating on international routes. The SIR for malignant melanoma of the skin was 10.20, 95% CI 3.29 to 23.81 in the total cohort and 15.63, 95% CI 5.04 to 36.46 in the restricted cohort. Analyses according to number of block-hours and radiation dose showed that malignant melanomas were found in the subgroups with highest exposure estimates, the SIRs were 13.04 and 28.57 respectively. The SIR was 25.00 for malignant melanoma among those who had been flying over five time zones.
CONCLUSIONS—The study shows a high occurrence of malignant melanoma among pilots. It is open to discussion what role exposure of cosmic radiation, numbers of block-hours flown, or lifestyle factors—such as possible excessive sunbathing—play in the aetiology of cancer among pilots. This calls for further and more powerful studies. The excess of malignant melanoma among those flying over five time zones suggests that the importance of disturbance of the circadian rhythm should be taken into consideration in future studies.


Keywords: cancer registry; malignant melanoma of the skin; cosmic radiation; block-hours; time zones     

Risk factors for fatigue among airline pilots

Purpose

The objective of this study is to determine risk factors for fatigue among airline pilots, taking into account person-, work-, health-, sleep-, and lifestyle-related characteristics.

Methods

The study population consisted of 502 pilots who participated in the MORE Energy study. Included risk factors were either measured through an online questionnaire or provided by the company. The outcome of this study, fatigue, was assessed using the Checklist Individual Strength (CIS), and was defined as scoring more than 76 points on this questionnaire. The association of the risk factors with fatigue was determined using univariate and multivariate logistic regression analyses.

Results

Of the participating pilots, 29.5 % scored more than 76 points on the CIS and were classified as being fatigued. The fully adjusted regression model showed that person-, work-, health-, and lifestyle-related characteristics were associated with fatigue. Pilots who were aged 31 to 40 (OR 3.36, 95 % CI 1.32–8.53) or 41 to 50 (OR 4.19, 95 % CI 1.40–12.47), an evening type (OR 2.40, 95 % CI 1.38–4.16), scored higher on work-life balance disturbance (OR 1.22, 95 % CI 1.10–1.36), scored higher on need for recovery (OR 1.02, 95 % CI 1.01–1.04), scored lower on general health perception (OR 0.31, 95 % CI 0.20–0.47), were less physically active (OR 0.77, 95 % CI 0.66–0.89), and had a moderate alcohol consumption (OR 3.88, 95 % CI 1.21–12.43), were at higher risk for fatigue.

Conclusions

Higher age, being an evening type, disturbance of the work-life balance, more need for recovery, a lower perceived health, less physical activity, and moderate alcohol consumption were shown to be risk factors for fatigue. Further longitudinal research is needed to elucidate the direction of the associations found and to evaluate the effects of possible countermeasures in airline pilots.

     

Mortality from cancer and other causes among airline cabin attendants in Europe: a collaborative cohort study in eight countries

There is concern about the health effects of exposure to cosmic radiation during air travel. To study the potential health effects of this and occupational exposures, the authors investigated mortality patterns among more than 44,000 airline cabin crew members in Europe. A cohort study was performed in eight European countries, yielding approximately 655,000 person-years of follow-up. Observed numbers of deaths were compared with expected numbers based on national mortality rates. Among female cabin crew, overall mortality (standardized mortality ratio (SMR) = 0.80, 95% confidence interval (CI): 0.73, 0.88) and all-cancer mortality (SMR = 0.78, 95% CI: 0.66, 0.95) were slightly reduced, while breast cancer mortality was slightly but nonsignificantly increased (SMR = 1.11, 95% CI: 0.82, 1.48). In contrast, overall mortality (SMR = 1.09, 95% CI: 1.00, 1.18) and mortality from skin cancer (for malignant melanoma, SMR = 1.93, 95% CI: 0.70, 4.44) among male cabin crew were somewhat increased. The authors noted excess mortality from aircraft accidents and from acquired immunodeficiency syndrome in males. Among airline cabin crew in Europe, there was no increase in mortality that could be attributed to cosmic radiation or other occupational exposures to any substantial extent. The risk of skin cancer among male crew members requires further attention.     

Breast cancer risk in airline cabin attendants: a nested case-control study in Iceland

Aims: To investigate whether length of employment as a cabin attendant was related to breast cancer risk, when adjusted for reproductive factors.

Methods: Age matched case-control study nested in a cohort of cabin attendants. The cases were found from a nationwide cancer registry (followed up to end of year 2000) and the reproductive factors (age at first childbirth and number of children) from a registry of childbirth, in both instances by record linkage with the cabin attendants' identification numbers. The employment time of the cabin attendants at the airline companies and the reproductive factors had been systematically recorded prior to the diagnosis of breast cancer in the cohort. A total of 35 breast cancer cases and 140 age matched controls selected from a cohort of 1532 female cabin attendants were included in the study.

Results: The matched odds ratio from conditional logistic regression of breast cancer risk among cases and controls of cabin attendants was 5.24 (95% CI 1.58 to 17.38) for those who had five or more years of employment before 1971 compared with those with less than five years of employment before 1971, adjusted for age at first childbirth and length of employment from 1971 or later.

Conclusions: The association between length of employment and risk of breast cancer, adjusted for reproductive factors, indicates that occupational factors may be an important cause of breast cancer among cabin attendants; the association is compatible with a long induction period.

     

A retrospective cohort mortality study of Italian commercial airline cockpit crew and cabin attendants, 1965-96

A retrospective cohort mortality study was conducted among Italian commercial flight personnel for the period 1965-1996. The cohort was composed of 3,022 male cockpit crew members and 3,418 male and 3,428 female cabin attendants. Cause-specific standardized mortality ratios (SMRs) and exact 95% confidence intervals (CIs) were calculated as estimates of the relative risk. Mortality from all cancers was less than expected for all categories (SMRs of 0.58 for male cockpit crew, 0.67 for male cabin attendants, and 0.90 for female cabin attendants). Among male flight personnel, the SMR for leukemia was somewhat elevated (SMR 1.73; 95% CI: 0.75-3.41) based on eight deaths, with a positive trend by length of employment (p = 0.046). Additionally, an excess of death by suicide was seen among female cabin attendants (SMR 3.38; 95% CI: 1.24-7.35). Other Italian studies of flight personnel are under way, including a detailed assessment of cosmic radiation exposure and investigations of non-radiation occupational risk factors and prevalence of nonfatal outcomes.     

Hearing status among cabin crew in a Swedish commercial airline company

Purpose  To study hearing loss in commercial airline cabin crew (CC). Methods  Totally 155 male and 781 female CC (n = 936) in a Swedish airline company underwent repeated audiometric tests during 1974–2005. The last test was used to study hearing loss. The mean test values at 3, 4, 6 kHz were used for the ear with worse hearing loss. Data were compared with a Swedish population (n = 603) who were not occupationally exposed to noise. Equivalent noise levels (Leq) were measured in different aircraft. Results  Leq was 78–84 dB (A), maximum A-weighted exposure was 114 dB. Median values for all ages were close to the reference group. No association was found between years of employment and hearing loss, when adjusting for age and gender by multiple logistic regression analysis. Conclusion  Cabin crew are exposed to equivalent noise levels below the current Swedish occupational standard, and have normal age-matched hearing threshold levels.     

Breast cancer risk among Finnish cabin attendants: a nested case-control study

Background: Earlier studies have found increased breast cancer risk among female cabin crew. This has been suggested to reflect lifestyle factors (for example, age at first birth), other confounding factors (for example, age at menarche), or occupational factors such as exposure to cosmic radiation and circadian rhythm alterations due to repeated jet lag.     

Mortality among pilots and cabin crew in Greece, 1960-1997

BACKGROUND: Specific health hazards, among them radiation of cosmic origin, have caused some concern among aircrew in civil aviation in recent years. Several cohort studies in Northern countries have investigated mortality and cancer incidence among aircrew. Our goal was to study the pattern of mortality among Greek commercial airline cockpit and cabin crew. METHODS: We performed a retrospective cohort study including 843 Olympic Airways cockpit crew and 1835 cabin attendants. Standardized mortality ratios (SMR) were calculated based on death rates of the Greek population. Duration of employment as a proxy for occupational exposure was used to stratify the cohort. RESULTS: For cockpit crew, the overall SMR was 0.7 (n = 65, 95% CI: 0.5-0.9). The SMR for all cancers was also significantly decreased (n = 17; SMR = 0.6; 95% CI: 0.3-0.9). Most of this reduction was due to a large deficit in lung cancer deaths (SMR = 0.1; 95% CI: 0.0-0.5). Slight but non-significant increases were noted for brain and liver cancer. The SMR for cardiovascular death was close to unity. Among female cabin attendants the SMR for all causes was 0.8 (95% CI: 0.4-1.3). The SMR for all cancers was 0.8 (95% CI: 0.3-1.7). Mortality from breast cancer was not increased. Among male cabin crew, SMR for all causes was 0.5 (95% CI: 0.3-0.9). Analyses according to duration of employment showed no pattern. CONCLUSIONS: In this first-ever occupational cohort study in Greece, Greek aircrew had a low overall and cancer mortality. Due to the small number of events, the strength of our study is limited. The Greek data will be included in a pooled analysis of European studies.     

Magnetic field exposure of commercial airline pilots

PURPOSE: Airline pilots are exposed to magnetic fields generated by the aircraft's electrical and electronic systems. The purpose of this study was to directly measure the flight deck magnetic fields to which commercial airline pilots are exposed when flying on different aircraft types over a 75-hour flight-duty month.METHODS: Magentic field measurements were taken using personal dosimeters capable of measuring magnetic fields in the 40-800 Hz frequency range. Dosimeters were carried by either the Captain or the First Officer on Boeing 737/200, Boeing 747/400, Boeing 767/300ER, and Airbus 320 aircraft. The data were analyzed by aircraft type, with statistics based on block hours. Block hours begin when the aircraft departs the gate prior to take off and end when the aircraft returns to the gate after landing.RESULTS: Approximately 1008 block hours were recorded at a sampling rate of 3 seconds. Total block time exposure to the pilots ranged from a harmonic geometric mean of 6.7 milliGauss (mG) for the Boeing 767/300ER to 12.7 mG for the Boeing 737/200.CONCLUSIONS: Measured flight deck magnetic field levels were substantially above the 0.8 to 1 mG level typically found in the home or office and suggest the need for further study to evaluate potential health effects of long-term exposure.     

Effects of onboard insecticide use on airline flight attendants

Flight attendants (FAs) exposed to insecticide spray in an aircraft were compared with unexposed subjects for neurobehavioral function, pulmonary function, mood states, and symptoms. The 33 symptomatic FAs were self-selected, and 5 had retired for disability. Testing procedures included balance, reaction time, color discrimination, visual fields, grip strength, verbal recall, problem solving, attention and discrimination functions, and long-term memory functions. Measurements were expressed as a percentage of their predicted values (derived from unexposed controls), and the author compared the means of the percentage predicted values by analysis of variance. Symptom frequencies and Profile of Mood States (POMS) scores were assessed. FAs were significantly more impaired than controls with respect to balance with eyes closed, grip strength, and color discrimination. Nearly half had 3 or more abnormal neurobehavioral functions, after adjustment was made for age, sex, and education level. Neither elevated POMS scores nor frequencies of average symptoms correlated with their numbers of abnormal measurements. Occupational exposure to synthetic pyrethrin insecticides on airliners was associated with neurobehavioral impairment and disability retirement.     

Pregnancy outcome among working women

The influence of occupational factors on the outcome of pregnancy was investigated in a prospective study of 3901 women who worked during their pregnancy and received prenatal care in Orebro County from October 1980 to June 1983. Data on occupational factors, social circumstances, and life-style factors were obtained from questionnaires. There were no significant differences in the incidence of adverse pregnancy outcome (spontaneous abortion, perinatal death, birth defects, or low birthweight) between the nine occupational categories used when nonoccupational factors were accounted for. No increased risk was found for exposure to organic solvents, but the adjusted risk ratio of adverse outcome was 1.28 (95% CI 0.91-1.80) for "other chemical exposures." The work conditions in this county have been generally favorable in recent years, and the results therefore cannot be generalized to conditions with higher exposures. Methodological problems such as misclassification of exposure and the possible bias resulting from different rates of legal abortions among occupational groups are discussed.     

Cosmic radiation and mortality from cancer among male German airline pilots: extended cohort follow-up

Commercial airline pilots are exposed to cosmic radiation and other specific occupational factors, potentially leading to increased cancer mortality. This was analysed in a cohort of 6,000 German cockpit crew members. A mortality follow-up for the years 1960-2004 was performed and occupational and dosimetry data were collected for this period. 405 deaths, including 127 cancer deaths, occurred in the cohort. The mortality from all causes and all cancers was significantly lower than in the German population. Total mortality decreased with increasing radiation doses (rate ratio (RR) per 10 mSv: 0.85, 95 % CI: 0.79, 0.93), contrasting with a non-significant increase of cancer mortality (RR per 10 mSv: 1.05, 95 % CI: 0.91, 1.20), which was restricted to the group of cancers not categorized as radiogenic in categorical analyses. While the total and cancer mortality of cockpit crew is low, a positive trend of all cancer with radiation dose is observed. Incomplete adjustment for age, other exposures correlated with duration of employment and a healthy worker survivor effect may contribute to this finding. More information is expected from a pooled analysis of updated international aircrew studies.     

Cancer incidence among male military and civil pilots and flight attendants: an analysis on published data

Flight personnel are exposed to cosmic ionizing radiation, chemicals (fuel, jet engine exhausts, cabin air pollutants), electromagnetic fields from cockpit instruments, and disrupted sleep patterns. Only recently has cancer risk among these workers been investigated. With the aim of increasing the precision of risk estimates of cancer incidence, follow-up studies reporting a standardized incidence ratio for cancer among male flight attendants, civil and military pilots were obtained from online databases and analysed. A meta-analysis was performed by applying a random effect model, obtaining a meta-standardized incidence ratio (SIR), and 95% confidence interval (CI). In male cabin attendants, and civil and military pilots, meta-SIRs were 3.42 (CI = 1.94-6.06), 2.18 (1.69-2.80), 1.43 (1.09-1.87) for melanoma; and 7.46 (3.52-15.89), 1.88 (1.23-2.88), 1.80 (1.25-2.58) for other skin cancer, respectively. These tumors share as risk factors, ionizing radiation, recreational sun exposure and socioeconomic status. The meta-SIRs are not adjusted for confounding; the magnitude of risk for melanoma decreased when we corrected for socioeconomic status. In civil pilots, meta-SIR was 1.47 (1.06-2.05) for prostate cancer. Age (civil pilots are older than military pilots and cabin attendants) and disrupted sleep pattern (entailing hyposecretion of melatonin, which has been reported to suppress proliferative effects of androgen on prostate cancer cells) might be involved. In male cabin attendants, meta-SIR was 21.5 (2.25-205.8) for Kaposi's sarcoma and 2.49 (1.03-6.03) for non-Hodgkin's lymphoma. AIDS, which was the most frequent single cause of death in this occupational category, likely explains the excess of the latter two tumors.     

Differences in physical workload between military helicopter pilots and cabin crew

Purpose

The 1-year prevalence of regular or continuous neck pain in military helicopter pilots of the Dutch Defense Helicopter Command (DHC) is 20 %, and physical work exposures have been suggested as risk factors. Pilots and cabin crew perform different tasks when flying helicopters. The aims of the current study were to compare the exposures to physical work factors between these occupations and to estimate the 1-year prevalence of neck pain in military helicopter cabin crew members.

Methods

A survey was completed by almost all available helicopter pilots (n = 113) and cabin crew members (n = 61) of the DHC. The outcome measures were self-reported neck pain and exposures to nine physical work factors. Differences in the proportions of helicopter pilots and cabin crew members reporting being often exposed to the particular physical factor were assessed with the χ ² test.

Results

The 1-year prevalence of regular or continuous neck pain among cabin crew was 28 %. Significantly more cabin crew members than pilots reported being often exposed to manual material handling, performing dynamic movements with their torsos, working in prolonged bent or twisted postures with their torsos and their necks, working with their arms raised and working in awkward postures. Often exposure to prolonged sitting and dynamic movements with the neck were equally reported by almost all the pilots and cabin crew members.

Conclusion

Flight-related neck pain is prevalent in both military helicopter pilots and cabin crew members. The exposures to neck pain-related physical work factors differ between occupations, with the cabin crew members subjected to more factors. These results have implications for preventative strategies for flight-related neck pain.