COHORT STUDY OF AIR CANADA PILOTS - MORTALITY, CANCER INCIDENCE, AND LEUKEMIA RISK

Despite the special working environment and exposures of airline pilot s, data on risk of death and cancer incidence in this occupational gro up are limited. The authors investigated a cohort of 2,740 Air Canada pilots who contributed 62,449 person-years of observation. All male pi lots employed for at least 1 year on and since January 1, 1950, were s tudied, 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 o f the cohort with the respective Canadian population rates. Ninety per cent confidence intervals of the SMR and SIR were calculated. Statisti cally 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 significant ly raised (SMR = 26.57, 90% CI 19.3-35.9). Significantly decreased can cer incidence was observed for all cancers (SIR = 0.71,90% CI 0.61-0.8 2), 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 0.12-0.8 2). Prostate cancer (SIR = 1.87, 90% GI 1.38-2.49) and acute myeloid l eukemia (SIR = 4.72, 90% CI 2.05-9.31) were significantly increased. T he preferred relative risk model for radiation-induced nonchronic lymp hoid leukemia (Beir V report) was applied to the cohort by using publi shed estimates of in-flight radiation exposures. The estimated relativ e 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 inciden ce rate of acute myeloid leukemia was significantly increased. Monitor ing of in-flight radiation exposure and long-term follow-up of civil a viation crew members is needed to further assess cancer incidence and leukemia risk in this special occupational group.