Pregnancy outcome among offspring of airline pilots and cabin attendants

OBJECTIVES: This study assessed the occurrence of perinatal death, low birthweight, preterm birth, and birth defects (total, major, neural tube defects, total cleft, cleft palate, hypospadias, and Down syndrome) in the offspring of airline pilots and cabin attendants. METHODS: A cohort of offspring of airline pilots and cabin attendants was established and characterized in terms of parental exposure to cosmic radiation the year before birth or ever. Pregnancy outcome was derived from the Medical Birth Register of Norway. The reference group comprised offspring of parents without occupational exposure to cosmic radiation. RESULTS: No deviant risks were observed for the offspring of male pilots, either for the year preceding birth (N=2,111) or ever (N=2,356). Specific birth outcomes were fewer for the pilots than for the referents (N=1,621,186), except for Down syndrome, which was more frequent [odds ratio (OR) 1.41, 95% confidence interval (95% CI) 0.53-3.76]. For exposure the year preceding birth (N=2,512), the risk of low birthweight was lower for the female cabin attendants than for the referents (adjusted OR 0.83, 95% CI 0.69-1.00), while Down syndrome was more frequent (OR 1.44, 95% CI 0.60-3.47). For exposure ever (N=3346), the risk of low birthweight was lower (OR 0.82, 95% CI 0.70-0.96) for the cabin attendants, while hypospadias (OR 1.18, 95% CI 0.61-3.04) and Down syndrome (OR 1.79, 95% CI 0.03-3.45) were more frequent CONCLUSIONS: In general, offspring of air pilots and cabin attendants do not seem to be at increased risk of adverse pregnancy outcome.     

Risk factors for cutaneous malignant melanoma among aircrews and a random sample of the population

Aims: To evaluate whether a difference in the prevalence of risk factors for malignant melanoma in a random sample of the population and among pilots and cabin attendants could explain the increased incidence of malignant melanoma which had been found in previous studies of aircrews.     

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.     

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.     

A Retrospective Cohort Mortality Study of Italian Commercial Airline Cockpit Crew and Cabin Attendants, 1965–96

Abstract

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 forall 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 persopnel, 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.     

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.     

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.     

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.     

Cancer incidence in airline cabin crew: experience from Sweden

Aims: To determine the cancer incidence in Swedish cabin crew.

Methods: Cancer incidence of cabin crew at the Swedish Scandinavian Airline System (SAS) (2324 women and 632 men) employed from 1957 to 1994 was determined during 1961–96 from the Swedish National Cancer Register. The cancer incidence in cabin crew was compared with that of the general Swedish population by comparing observed and expected number of cases through standardised incidence ratios (SIR). A nested case-control study was performed, including cancer cases diagnosed after 1979 and four controls per case matched by gender, age, and calendar year.

Results: The SIR for cancer overall was 1.01 (95% CI 0.78 to 1.24) for women and 1.16 (95% CI 0.76 to 1.55) for men. Both men and women had an increased incidence of malignant melanoma of the skin (SIR 2.18 and 3.66 respectively) and men of non-melanoma skin cancer (SIR 4.42). Female cabin attendants had a non-significant increase of breast cancer (SIR 1.30; 95% CI 0.85 to 1.74). No clear associations were found between length of employment or cumulative block hours and cancer incidence.

Conclusions: Swedish cabin crew had an overall cancer incidence similar to that of the general population. An increased incidence of malignant melanoma and non-melanoma skin cancer may be associated with exposure to UV radiation, either at work or outside work. An increased risk of breast cancer in female cabin crew is consistent with our results and may in part be due to differences in reproductive history.

     

A comparison of melanoma mortality among WWII veterans of the Pacific and European theaters

PURPOSE: To determine whether cutaneous melanoma is associated with past military service in tropical locations, as a test of the 'critical period' sunlight exposure hypothesis. METHODS: Mortality data from a longitudinal follow-up study of 5524 former prisoners of war (POW) and 3713 non-POW veteran controls, all white male veterans of World War II (WWII), were examined to determine whether death attributed to melanoma was associated with history of military service in Pacific or European theaters during WWII or with POW status. Deaths from colon cancer were used as a comparison outcome. RESULTS: During 50 years of follow-up, there were 18 deaths from melanoma and 83 deaths from colon cancer among the cohort. Melanoma mortality varied with theater of war and POW status, whereas colon cancer mortality was similar for all subgroups. Pacific War POWs were at the highest risk overall (odds ratio (OR), 3.35; 95% confidence interval (CI), 0.39-28.76), whereas veterans of the Pacific War had nearly the same risk of melanoma (OR, 1.04; 95% CI, 0.09-11.94) compared with veterans of the European War. European theater POWs had a higher risk than non-POW veterans (OR, 2.76; 95% CI, 0.31-24.81). None of these differences, however, were statistically significant. CONCLUSIONS: To the extent that POW status is associated with higher sun exposure, these data are consistent with the hypothesis that exposure to high levels of solar radiation in young adulthood is associated with a higher risk of melanoma mortality.     

Spontaneous abortions among Finnish flight attendants.

We conducted a retrospective cohort study to investigate whether work as a cabin attendant is related to an increased risk for spontaneous abortion. Data on female cabin crew members were linked to medical records on pregnancies. There were 1751 eligible pregnancies for the final analysis. Flight attendants who worked during early pregnancy had a slightly elevated risk of spontaneous abortion, as compared with attendants who were pregnant outside a time span of active flying (odds ratio [OR] = 1.3; 95% confidence interval [CI], 0.9 to 1.8). During the earliest years of the study period (1973 through 1977), the risk seemed to be decreased (OR = 0.4; 95% CI, 0.2 to 1.1), whereas during the later years (1978 through 1994) the risk was increased (OR = 1.6; 95% CI, 1.1 to 2.4). The results are in agreement with earlier studies, showing suggestive evidence of a slightly increased risk of spontaneous abortion among female cabin crew members.     

Sociodemographic status, stress, and risk of prostate cancer. A prospective cohort study

PURPOSE: The social gradient in prostate cancer incidence observed in several studies may be a result of differential access to prostate cancer screening. We aim to assess if socioeconomic status, stress, and marital status are associated with prostate cancer risk in a population with free access to health care. METHODS: The 5,496 men who participated in the Copenhagen City Heart Study were asked about their income, educational level, stress level, and marital status during 1981-1983. These men were prospectively followed up in the Danish Cancer Registry until the end of 2002 and fewer than 0.1 % were lost to follow-up. RESULTS: During follow-up, 157 men were diagnosed with prostate cancer. Neither high income (HR = 1.17, 95% confidence interval [CI]: 0.78-1.76) nor high education (HR = 1.22; 95% CI: 0.76-1.96) were associated with risk of prostate cancer. There were also no differences in prostate cancer risk according to stress (HR = 0.99; 95% CI: 0.90-1.09) or marital status. CONCLUSION: In a racially homogeneous population of Caucasians with free access to health care, we found no evidence of a relation between sociodemographic variables or stress and subsequent risk of prostate cancer.     

Decreased risk of prostate cancer after skin cancer diagnosis: a protective role of ultraviolet radiation?

Ultraviolet radiation causes skin cancer but may protect against prostate cancer. The authors hypothesized that skin cancer patients had a lower prostate cancer incidence than the general population. In the southeastern part of the Netherlands, a population-based cohort of male skin cancer patients diagnosed since 1970 (2,620 squamous cell carcinomas, 9,501 basal cell carcinomas, and 1,420 cutaneous malignant melanomas) was followed up for incidence of invasive prostate cancer until January 1, 2005, within the framework of the Eindhoven Cancer Registry. The incidence rates of prostate cancer among skin cancer patients were compared with those in the reference population, resulting in standardized incidence ratios. Skin cancer patients were at decreased risk of developing prostate cancer compared with the general population (standardized incidence ratio (SIR) = 0.89, 95% confidence interval (CI): 0.78, 0.99), especially shortly after diagnosis. The risk of advanced prostate cancer was significantly decreased (SIR = 0.73, 95% CI: 0.56, 0.94), indicating a possible antiprogression effect of ultraviolet radiation. Patients with a skin cancer in the chronically ultraviolet radiation-exposed head and neck area (SIR = 0.84, 95% CI: 0.73, 0.97) and those diagnosed after the age of 60 years (SIR = 0.86, 95% CI: 0.75, 0.97) had decreased prostate cancer incidence rates. These results support the hypothesis that ultraviolet radiation protects against prostate cancer.     

Is diabetes mellitus associated with prostate cancer incidence and survival?

Results of two recent prospective incidence studies have suggested that certain subgroups of men with diabetes mellitus may be protected from developing prostate cancer. Two earlier studies, however, concluded that diabetes increased the risk of mortality from prostate cancer. With hundreds of thousands of male respondents, the 1959-1972 Cancer Prevention Study provided a unique opportunity to explore whether men with diabetes were more likely to develop prostate cancer during a 13-year follow-up period than were men without diabetes. After adjusting for factors associated with prostate cancer in previous studies, we found little association between diabetes at baseline and prostate cancer incidence [incidence density ratio (IDR) = 1.05; 95% confidence interval (CI) = 0.81-1.36]. Men who had diabetes mellitus for 5 or more years, however, had a higher incidence of prostate cancer than did men without diabetes (IDR = 1.56; 95% CI = 1.02-2.38). Among all study participants who were diagnosed with prostate cancer, men with diabetes were only slightly more likely to die from prostate cancer than were men without diabetes (IDR = 1.11; 95% CI = 0.76-1.62).     

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.     

Second primary cancers following anal and cervical carcinoma: evidence of shared etiologic factors.

The authors examined the incidence of second primary cancers occurring after cervical and anal cancer. Data from the Connecticut Tumor Registry for 1935-1988 and eight other US tumor registries for 1973-1988 were used. Women with primary invasive cervical cancer had a relative risk of 4.6 (95% confidence interval (CI) 2.4-8.1) for subsequent invasive anal cancer. Increased relative risks after cervical cancer were also found for cancers of the oral cavity (relative risk (RR) = 2.2), stomach (RR = 1.5), rectum (RR = 1.4), larynx (RR = 3.4), lung (RR = 3.0), vagina (RR = 5.6), bladder (RR = 2.7), for kidney (RR = 1.9); decreased relative risks were noted for melanoma (RR = 0.5) and breast cancer (RR = 0.8). Patients with a primary diagnosis of anal cancer had relative risks for subsequent invasive and in situ cervical cancer of 1.3 (95% CI 0.2-4.5) and 3.4 (95% CI 0.9-8.8), respectively. Anal cancer was also associated with increased relative risks of subsequent lung (RR = 2.5) and prostate (RR = 1.8) cancers, whereas the relative risk of uterine cancer was 0.2 (95% CI 0.0-0.9). These findings support other evidence for common factors, such as human papillomavirus infection and cigarette smoking, in the etiology of cervical and anal cancer.     

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.

     

Occupational radiation dose estimation for Finnish aircraft cabin attendants

OBJECTIVES: The objective of this study was to develop a method for assessing dose radiation on the basis of individual flight history and to estimate whether this method is applicable for cabin attendants without flight log data. METHODS: Questionnaire data were collected to determine attendants' flight history covering up to three decades. Finnair timetables and an expert panel of pilots were used to determine one to four representative flights in five route categories. The cumulative career and annual doses were calculated on the basis of the flight histories and route-specific exposure data. RESULTS: Questionnaire data were obtained from 544 flight attendants. The mean number of active workyears was 10.5 (range 0-30) years, and the mean cosmic radiation dose was 3.2 (range 0-9.5) mSv per active workyear. The mean cumulative career dose for all the cabin attendants was 34.0 (range 0-156.8) mSv. CONCLUSIONS: If no flight log data are available, survey data are needed for individual dose estimation when possible radiation effects on cabin crew are evaluated in epidemiologic studies. This method provides a crude procedure for assessing cosmic radiation exposure among attendants when survey data are missing.     

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.     

Cohort cancer incidence among pulp and paper mill workers in British Columbia.

OBJECTIVES: A study was conducted to investigate cancer risks in a cohort of pulp and paper workers. METHODS: All male workers with > or =1 years of employment in 14 pulp and paper mills in 1950-1992 were studied. Standardized incidence ratios (SIR) were used to compare the cancer incidence of the cohort with that of the Canadian male population. Record linkage with the National Cancer Registry was performed using the generalized iterative record linkage method. RESULTS: Altogether 1756 cancer cases were observed in the entire cohort. For > or =15 years of work, the entire cohort had significantly increased SIR values for pleural and prostate cancer and skin melanoma; there was also a significantly increased risk for skin melanoma among workers in the kraft process only, rectal cancer among workers in the sulfite process only, and stomach and prostate cancer and all leukemias combined among workers in both the kraft and sulfite processes. A separate analysis comparing workers in pulping and papermaking with those in the pulping process only did not reveal any difference in cancer risk and hence did not modify the results. The SIR values for skin melanoma were not significantly increased in a comparison using the British Columbia male population. Nine of 10 pleural cancers were mesotheliomas, which likely reflect past asbestos exposure. CONCLUSIONS: The results suggest that long-term work in the pulp and paper industry is associated with excess risks of prostate and stomach cancers and all leukemias for work in both kraft and sulfite processes and of rectal cancer for work in the sulfite process only.