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Determination of the Risk of Radiation-Associated Circulatory and Cancer Disease Mortality in a NASA Early Astronaut Cohort Of the many possible health challenges posed during extended exploratory missions to space, the effects of space radiation on cardiovascular disease and cancer are of particular concern. There are unique challenges to estimating those radiation risks; care and appropriate and rigorous methodology should be applied when considering small cohorts such as the NASA astronaut population. The objective of this work was to determine if there was sufficient evidence for excess risk of cardiovascular disease and cancer in early NASA astronaut cohorts. NASA astronauts in selection groups 1-7 were chosen; this relatively homogeneous cohort consists of 73 white males, who unlike today's astronauts, maintained similar smoking and drinking habits to the general US population, and have published radiation doses. The participants flew in space on missions Mercury through Shuttle and received space radiation doses between 0-74.1 milligrays. Cause of death information was obtained from the Lifetime Surveillance of Astronaut Health (LSAH) program at NASA Johnson Space Center. Mortality was compared with the US male population. Trends of mortality with dose were assessed using a logistic model, fitted by maximum likelihood. Only 32 (43.84 percent) of the 73 early astronauts have died. Standard mortality ratios (SMRs) for cancer (n=7, SMR=43.4, 95 percent CI 17.8, 84.9), all circulatory disease (n=7, SMR=33.2, 95 percent CI 13.7, 65.0), and ischemic heart disease (IHD) (n=5, SMR=40.1, 95 percent CI 13.2, 89.4) were significantly lower than for the US white male population. For cerebrovascular disease, the upper confidence interval for SMR included 100, indicating it was not significantly different from the US population (n=2, SMR = 77.0, 95 percent CI 9.4, 268.2). The power of the study is low and remains below 10 percent even when risks 10 times those reported in the literature are assumed. Due to small sample size, there is currently insufficient statistical power to evaluate space radiation exposure effects on mortality in NASA astronauts. In addition to a comprehensive longitudinal study of NASA astronauts, a research strategy of low dose epidemiology data integration with cell and animal studies should be utilized for space radiation risk assessment in the astronauts.
Document ID
20170004342
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Elgart, S. R.
(KBRwyle Science, Technology and Engineering Houston, TX, United States)
Chappell, L.
(KBRwyle Science, Technology and Engineering Houston, TX, United States)
Milder, C. M.
(NASA Johnson Space Center Houston, TX, United States)
Shavers, M. R.
(KBRwyle Science, Technology and Engineering Houston, TX, United States)
Huff, J. L.
(MEI Technologies, Inc. Houston, TX, United States)
Little, M.
(National Cancer Inst. Bethesda, MD, United States)
Patel, Z. S.
(KBRwyle Science, Technology and Engineering Houston, TX, United States)
Date Acquired
May 3, 2017
Publication Date
October 15, 2017
Subject Category
Aerospace Medicine
Report/Patent Number
JSC-CN-39535
Meeting Information
Meeting: Radiation Research Society (RRS)
Location: Cancun
Country: Mexico
Start Date: October 15, 2017
End Date: October 18, 2017
Sponsors: Radiation Research Society
Distribution Limits
Public
Copyright
Public Use Permitted.
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