posted 07-28-2016 01:24 PM               

Apollo astronauts experiencing higher rates of cardiovascular-related deaths

Members of the successful Apollo space program are experiencing higher rates of cardiovascular problems that are thought to be caused by their exposure to deep space radiation, according to a Florida State University researcher.

In a new paper in Scientific Reports, FSU Dean of the College of Human Sciences and Professor Michael Delp explains that the men who traveled into deep space as part of the lunar missions were exposed to levels of galactic cosmic radiation that have not been experienced by any other astronauts or cosmonauts. That exposure is now manifesting itself as cardiovascular problems.

"We know very little about the effects of deep space radiation on human health, particularly on the cardiovascular system," Delp said. "This gives us the first glimpse into its adverse effects on humans."

This is the first study looking at the mortality of Apollo astronauts. The Apollo program ran from 1961 to 1972, with 11 manned flights into space between 1968 and 1972. Nine of those flew beyond Earth's orbit into deep space. The program is most notable for landing men on the moon as well as the failed mission of Apollo 13 that inspired the popular 1995 Ron Howard film.

Delp's research is of special interest now as the United States and other nations, plus private organizations, make plans for deep space travel. NASA has unveiled plans for U.S. orbital missions around the moon from 2020 to 2030 in preparation for a manned flight to Mars. Russia, China and the European Space Agency are all looking at lunar missions. And SpaceX, owned by Elon Musk, has proposed landing humans on Mars by 2026.

As a group, astronauts are highly educated and have access to top medical care, meaning their healthcare outcomes are generally better than the general population. But the group of men in the Apollo program experienced different environmental conditions than anyone else in the world when they traveled into deep space.

Delp found that 43 percent of deceased Apollo astronauts died from a cardiovascular problem. That is four to five times higher than non-flight astronauts and astronauts who have traveled in low Earth orbit.

Of the 24 men who flew into deep space on the Apollo lunar missions, eight have died and seven were included in the study. The eighth — Edgar Mitchell — died after the data analysis had been completed.

Delp and his colleagues also exposed mice to the type of radiation that Apollo astronauts would have experienced. After six months — the equivalent of 20 human years — the mice demonstrated an impairment of arteries that is known to lead to the development of atherosclerotic cardiovascular disease in humans.

"What the mouse data show is that deep space radiation is harmful to vascular health," Delp said.

Delp is working with NASA to conduct additional studies on the Apollo astronauts regarding their cardiovascular health.

This research was funded by National Space and Biomedical Research Institute and the NASA Space Biology Program. Other authors on the paper include Jacqueline Charvat from Johnson Space Center, Charles Limoli from University of California Irvine, Ruth Globus from the NASA Ames Research Center and FSU postdoctoral researcher Payal Ghosh.

posted 07-28-2016 03:27 PM               

• They are using an extremely small population from which to base their findings. To be clear, their calculation of 43% of deaths is based on the deaths of only three people: Neil Armstrong, Jim Irwin, and Ron Evans. Such a small sampling group is statistically irrelevant.

• Cardiovascular disease is the leading killer of Americans. In such a small sampling group as lunar-flown Apollo astronauts, it only takes an extra death or two from a particular disease to really shift the percentages. Irwin experienced cardiac irregularities while on the lunar surface, so it could be argued that he may have had a predisposition to heart problems before he ever flew to the moon.

• Comparing against other astronauts who have only flown in low earth orbit will not necessarily provide a valid comparison, unless one only compares against astronauts of the same age group. Shuttle astronauts comprise the majority of the flown astronaut population, and are generally younger than the Apollo astronauts. Therefore, Shuttle astronauts who have passed to date are more likely to have succumbed to other diseases or accidents more common to a younger population. As they age, one can expect to see a rise in deaths associated with older populations... including cardiovascular disease.

posted 07-28-2016 03:43 PM               

Dr. Delp said his team felt that it was important to release their findings, even with shortcomings.

"What it does is point to the fact that we need a lot more study on this," he said. "One of the things that NASA and others have been most concerned about with space radiation is cancer. The cardiovascular system has barely gotten mentioned."

"With only 10 years before people are planning to send people back to deep space, we thought, 'We can sit on this study, or we can try to get it out there,'" Dr. Delp said. "We felt it was important enough to get it out."

posted 07-28-2016 07:15 PM               

That leaves nine natural deaths among the non-lunar astronauts for which the causes are generally known. Of those deaths, three were due to cardiovascular disease (33% of the total). Two others had other diseases, but ultimately fell to heart attacks or heart failure (bringing the percentage up to 56%). The remaining four were either due to cancer (2) or other health issues (2).

Statistically speaking, the cardiovascular death rate is basically identical to the three lunar-flown astronauts (out of seven total for whom causes of death are publicly known) who died of cardiovascular disease (43%). Certainly, it is not "four or five times higher" as the article states.

Again, it's important to remember that cardiovascular disease (heart disease and strokes) accounts for roughly 29% of all deaths by white males in the United States, followed closely by cancer at around 24%. Those numbers for heart disease and cancer tend to be higher once you get over the age of 60.

posted 07-28-2016 08:19 PM               

It would appear to be unwarranted and, perhaps, even unethical to release a scientific report while admitting to knowing that there are shortcomings due to lack of data points.

To take 12 humans and interpolate medical data to make a huge assumption that the deep space astronauts had a higher than average death rate from heart disease is not really rational. One twelfth of the moonwalkers died in motorcycle accidents, therefore a majority of the astronaut corp is adverse to motorcycles.

posted 07-29-2016 07:02 AM               

Nine of the 14 members of the 1963 astronaut group are still alive and all are in their 80s. Only one of them has died from natural causes (Eisele, heart attack). Five of the nine-man 1962 group are still kicking, with only Armstrong dying from natural causes. Five from the six-member 1965 group, 11 of the 19-man 1966 group, seven of the "XS-11" group and four of the seven-man MOL-to-NASA group.

Only the Original 7 group has a lesser number with Glenn (the oldest and earliest born of all the astronauts, and thus far the only NASA astronaut to make it to age 90) the only surviving member.

posted 07-29-2016 08:28 AM               

The Galatic Cosmic Rays — a small but important part of which are also known as "high (or heavy) Z ions" — clearly pack a punch and have cancer implications... Big DNA splits and gene damage.

Additionally, even within the Earth's atmosphere, there now seem to be some clear ties between cardiovascular disease and ionizing radiation. NCRP has a big "million worker study" going on that is looking closely at all these aspects (not GCRs though). And if you aren't aware, more info is coming to light about severe cognitive degradation and neuron destruction from these high Z ionized particles.

Here's a brief popular article on the cognitive implications (not a medical journal piece).

posted 07-29-2016 01:00 PM               

quote:

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Originally posted by MCroft04:
I agree; a very weak study. And from my Florida State.

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posted 07-29-2016 03:39 PM               

However I don’t see how this study moves the needle on that topic in any way. As has been mentioned already, the sample size is just too small, the Apollo mission durations too short, and the flights in question produced many very active and fit octogenarian crew-members.

Like others, I toss out Jim Irwin as a study sample. There was a robust CS thread on Irwin a few months back. Whether he had a heart attack during the Apollo 15 mission or not can be debated, but he certainly suffered heart irregularities. I don’t see how his case could legitimately be used in this long term study.

posted 07-29-2016 08:15 PM               

Along with previously mentioned family history as a cardiovascular risk factor, poor diet is probably the biggest risk factor, i.e. cholesterol, saturated fats, triglycerides, etc.

posted 08-11-2016 03:12 PM            

quote:

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Originally posted by OV-105:
Funny that it was not brought up that none of the astronauts who flew to the moon twice were exposed to twice as much as the others who passed from heart disease.

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