Mortality Among U.S. Astronauts: 1980–2009

Abstract

It has been nearly 20 yr since the first published astronaut mortality analysis. Using astronaut vital data and general population mortality rates, we calculate Standardized Mortality Ratios (SMR) for both total and specific causes of death among astronauts between January 1980 and June 2009 to look for changes in mortality patterns over time. Astronaut vital data were derived from the Johnson Space Center website and the Astronaut Fact Book. General population mortality rates were taken from the Human Mortality Database and the Centers for Disease Control. SMR were computed as the ratio of observed deaths to expected deaths using indirect standardization to several comparison populations. All SMR declined from the 1980s to the 2000s, though astronauts are still at increased risk of accidental death (SMR = 574, 95% C.I. 335-919). Astronauts are at greatly reduced risk of death by cardiovascular disease (SMR = 27, 95% C.I. 9-63) and cancer (SMR = 47, 95% C.I. 19-97), and astronauts are now at decreased risk of all-cause mortality compared with the general population. The SMR show that mortality from circulatory disease, cancer, and accidents have all declined from previous estimates, though astronauts are still at increased risk of accidental death. Improvements in circulatory disease mortality are likely due to intensive health screening and physical fitness within the Astronaut Corps. Similarly, physical fitness may be contributing to the reduction in cancer mortality. Fewer airplane crashes have contributed to the decreased risk of fatal accidents, which in turn is driving the reduction in all-cause mortality risk.