Cohort mortality study of German cockpit crew, 1960-1997

Background. Cockpit crew in civil aviation are exposed to several potential health hazards, among them cosmic ionizing radiation. To assess the influence of occupational and other factors on mortality we conducted a cohort study among cockpit crew. Methods. All pilots and other cockpit personnel of two German airlines were traced through registries and other sources for the period 1960-1997. Standardized mortality ratios, with German population rates as the reference, were calculated. We estimated the individual radiation dose based on individual job histories and assessed dose-response trends in stratified and regression analyses. Results. We compiled a cohort of 6061 male cockpit personnel, yielding 105,037 person-years of observation. The maximum estimated individual radiation dose was 80.5 mSv. Among 255 deaths overall (standardized mortality ratio [SMR] = 0.48; 95% confidence interval [CI] = 0.42-0.54) there were 76 cancer deaths (SMR = 0.56; CI = 0.43 - 0.74). Most cancer and cardiovascular SMRs were reduced. A slight increase was seen for brain cancer (SMR = 1.68; CI = 0.66-3.62). Employment duration was associated with the all-cancer mortality in Poisson regression analyses. No other dose-response relation was found. Conclusions. German cockpit crew have a low overall and cancer mortality. The role of occupational causes, and particularly cosmic radiation, appears limited.