Putting Too Much Heart into Space Exploration? Cardiovascular Disease and Cancer in Astronauts

The effect of space radiation on astronaut health has always been a concern of NASA and its astronauts. With space flight, there are numerous possible health challenges that can occur, but radiation and its effect on cardiovascular disease and cancer is at the top of NASA’s list. The difficulties and costs of space travel make it hard to measure these effects. In spite of these challenges, in 2018 researchers at The University of Texas, National Cancer Institute, NASA Johnson Space Center, and MEI Technologies conducted an observational cohort study of astronauts and found that there was no over exaggerated risk of cancer or cardiovascular disease due to space radiation. However, these results were not completely conclusive and doubts still remain.

The team selected astronauts from 1959 to 1969 and looked at their medical records from birth to death, or 2016, which ever came first. Their data was collected from the Lifetime Surveillance of Astronaut Health program at the NASA Johnson Space Center. The astronauts that were used in the study participated in the Mercury through Space Shuttle programs.  A diverse population was not possible as all astronauts of the time were white males, and some of the included subjects never even flew a space mission.  In total, there were 73 white males (49 living and 34 deceased) that participated in the study.  The health hazards of smoking were not well known at the time, so this group maintained similar smoking patterns as the general U.S. population.  It would be much more difficult to find a single astronaut that smokes today! NASA carefully measures radiation exposure to its astronauts and the total doses ranged from 0 to 74.1 mGy (milligrays). After comparing with the United States white male population, the overall mortality rates of the astronauts that were used in the test fell well below the national average!

Although the researchers found that space radiation doesn’t lead to risk of cancer or cardiovascular disease, they decided that the findings were not conclusive, only because they used such a small sample. It is also possible that the astronauts in the population had a reduced cardiac risk because they were in better physical condition than the average U.S. white male of the time. The researchers want to look more into this topic by using epidemiology data with cell and animal studies to back up their findings on the risk of space radiation.

Link:  https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170009911.pdf

Elgart, S.R., Little, M. P., Campbell, L. J., Milder, C. M., Shavers, M. R., Huff J. L., Patel, Z. S. Radiation Exposure and Mortality from Cardiovascular Disease and Cancer in Early NASA Astronauts: Space for Exploration. NASA Technical Reports Sever: JSC-CN-40709.