Cohort Study of Air Canada Pilots: Mortality, Cancer Incidence, and Leukemia Risk

Abstract

Despite the special working environment and exposures of airline pilots, data on risk of death and cancer incidence in this occupational group are limited. The authors investigated a cohort of 2,740 Air Canada pilots who contributed 62,449 person-years of observation. All male pilots employed for at least 1 year on and since January 1, 1950, were studied. The cutoff date for outcome information was December 31, 1992. Standardized mortality ratio (SMR) and standardized incidence ratio (SIR) were used to compare mortality rates and cancer incidence rates of the cohort with the respective Canadian population rates. Ninety percent confidence intervals of the SMR and SIR were calculated. Statistically significant decreased mortality was observed for all causes (SMR = 0.63, 90% confidence interval (CI) 0.56-0.70), for all cancers (SMR = 0.61, 90% CI 0.48-0.76), and for all noncancer diseases (SMR = 0.53, 90% CI 0.45-0.62). Mortality from aircraft accidents was significantly raised (SMR = 26.57, 90% CI 19.3-35.9). Significantly decreased cancer incidence was observed for all cancers (SIR = 0.71, 90% CI 0.61-0.82), rectal cancer (SIR = 0.42, 90% CI 0.14-0.96), lung cancer (SIR = 0.28, 90% CI 0.16-0.46), and bladder cancer (SIR = 0.36, 90% CI 0.12-0.82). Prostate cancer (SIR = 1.87, 90% CI 1.38-2.49) and acute myeloid leukemia (SIR = 4.72, 90% CI 2.05-9.31) were significantly increased. The preferred relative risk model for radiation-induced nonchronic lymphoid leukemia (Beir V report) was applied to the cohort by using published estimates of in-flight radiation exposures. The estimated relative risk ranged from 1.001 to 1.06 and did not differ significantly from the observed SIR (SIR = 1.88, 90% CI 0.80-3.53). However, the incidence rate of acute myeloid leukemia was significantly increased. Monitoring of in-flight radiation exposure and long-term follow-up of civil aviation crew members is needed to further assess cancer incidence and leukemia risk in this special occupational group.

Epidemiologic estimate of the proportion of fatalities related to occupational factors in Finland

“…Whereas nonmelanocytic skin cancers occur with increased risk in the occupational groups most exposed to sunlight, the highest risks for malignant melanomas are often registered in indoor occupations. For these cancer types, excess risks have been reported in studies on airline pilots conducted in Finland (79), Canada (146,147), the United States (148), Iceland (149), and Norway (150). In the Norwegian study (150), an increasing trend was observed for the standardized incidence rate with a cumulative dose for malignant melanoma.…”

Clock-cancer connection in non-Hodgkin’s lymphoma

“…Currently, a cohort of men working for Air Canada, however, showed a significantly increased incidence rate of acute myeloid leukemia (SIR = 4.72, 90% CI 2.05-9.31) when compared to the respective Canadian population rates [15]. There is also a case report showing that a patient with primary cerebral B-cell non-Hodgkin's lymphoma lost circadian control of sleep [16].…”

Variants in circadian genes and prostate cancer risk: a population-based study in China

“…For example, rotating shift workers had a higher risk of prostate cancer as compared with only day-or only night-shift workers. 6,7 In addition, male airline pilots had an excess risk of prostate cancer [8][9][10] that increased with the increasing number of flight hours. 10 Although compelling, these data represent indirect associations between circadian rhythms and prostate cancer; no underlying molecular mechanism thus far has been identified.…”