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Study: Astronauts Who Reach Deep Space 'Far More Likely To Die From Heart Disease' (independent.co.uk)

An anonymous reader quotes a report from The Independent: Astronauts who venture into deep space appear to be much more likely to die from heart disease, according to a new study. In another sign that leaving planet Earth is fraught with danger and a potential blow to hopes of establishing a colony on Mars, researchers discovered deep space radiation appears to damage the body's cardiovascular system. They reported that three out of the seven dead Apollo astronauts died as a result of a cardiovascular disease, such as a heart attack or stroke. Although the numbers are small, that rate of 43 percent is four to five times higher than found among astronauts who flew in low Earth orbit or who did not actually go into space, according to a paper in the journal Scientific Reports. In an attempt to test whether the higher numbers of cardiovascular deaths were simply a statistical blip or a genuine sign of the effect of traveling into deep space, the scientists exposed mice to the same type of radiation that the astronauts would have experienced. After six months, which is the equivalent of 20 human years, the mice showed damage to arteries that is known to lead to the development of cardiovascular disease in humans.

33 of 157 comments (clear)

  1. Ionizing radiation linked to circulatory disease by Anonymous Coward · · Score: 4, Insightful

    I don't see why this would be a surprise but at the statistical rigor level we're talking about dozens of people being used for heart studies. Even with NASA's predilection for perfection there's no way to isolate deep space causal to heart disease or much else with as few individuals as we're ever measuring from.

  2. Sounds Familiar. by lobiusmoop · · Score: 5, Interesting

    FTFA:

    Professor Michael Delp, one of the researchers, said: "We know very little about the effects of deep space radiation on human health, particularly on the cardiovascular system."

    We do however know a lot about the effects of terrestrial radiation on human heath... a long-term side effect of radiation therapy to the chest area can be a increased risk of heart disease... apparently. :-/

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    1. Re: Sounds Familiar. by Rei · · Score: 3, Interesting

      This was known and discussed. But they found microgravity to be a compounding effect of radiation exposure

      This just drives home how much of a risk interplanetary flight is right now. And we really don't have great solutions that don't involve great masses of shielding. Artificial magnetosopheres for example are insufficient to deal with GCR.

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    2. Re:Sounds Familiar. by Anonymous Coward · · Score: 2, Insightful

      Yes, but stress also causes heart problems.
      I suspect deep space missions typically causes more stress than low orbit missions but that is just speculative, just like most of this discussion.

    3. Re: Sounds Familiar. by lexman098 · · Score: 2

      Being ignorant here, but faraday cages aren't that heavy relative to lead shielding. Are they effective for this type of radiation?

      No, this is particle radiation as opposed to an electromagnetic signal.

  3. The 60's kills in slow motion by He+Who+Has+No+Name · · Score: 4, Insightful

    Did anybody bother to control for the prevalence of smoking and other environmental factors that may not be in play for most individuals 50 years later?

    Mission Control looked like a nicotine hotbox half the time back then, and astronauts rotated through as CAPCOM. And that's not even starting to consider what else they may have been deliberately or accidentally exposed to during the early space program.

    1. Re:The 60's kills in slow motion by Alomex · · Score: 4, Informative

      No they didn't. Luckily there is such a bright mind as yourself to point the obvious...

      If you read the article (yeah, I know, who does?) they used all other lower orbit astronauts as a control group, who had similar diets, smoking and drinking habits and level of fitness and stress.

    2. Re:The 60's kills in slow motion by DarkOx · · Score: 2

      We really don't understand the relationship between diet and longevity yet. There is ample evidence to suggest that steak and eggs for breakfast at high frequency isn't a good health move for you and I. When you control for the population that also does a lot of physical labor most days, like farmers, landscapers, miners, etc than suddenly high fat/cholesterol, high animal protein diets don't seem to lead to heart disease and other conditions like diabetes nearly so often.

      There is a relationship between what we should eat and how we use our bodies and its more complex than more work, means more calories or more sedentary means eat less.

      We simply don't have enough astronauts and cosmonauts to do a good study and make more than a token effort to control other factors like tossing out a couple of extreme outlines or exuding an individual known to have made some unusual life style choices post mission. This is a situation where we have to make some anecdotally informed guesses. Its simply the best that can be done.

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    3. Re:The 60's kills in slow motion by Archtech · · Score: 2

      There is ample evidence to suggest that steak and eggs for breakfast at high frequency isn't a good health move for you and I.

      That turns out not to be the case. Certainly until you cite a sufficient number of studies that prove your point - of which, I submit, there are none. The salient fact is that those who claim "that steak and eggs for breakfast at high frequency isn't a good health move" can't point to any actual scientific evidence - just a huge amount of, "he said, she said".

      It is certainly true that most people don't need to eat breakfast at all: a good pattern is to eat two meals, one at about noon and one at about 6 p.m. That gives your body time to get into the "fasting state" where it uses up a little of its own fat, rather than having it saturated with glucose 24 hours a day. But whenever you do eat, steak and eggs are hard to beat (if you can afford them), especially if accompanied by plenty of green leafy vegetables, some nuts and seeds, and a little fruit and dairy.

      And incidentally, that should be "for you and me".

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    4. Re:The 60's kills in slow motion by bfpierce · · Score: 2

      Curious where you're seeing they controlled for 'similar diet, smoking, drinking habits' when that's not mentioned either in the article or the actual paper.

      Group sampling methods are pretty well spelled out in that paper, and yet, not seeing it.

  4. Seven? by tsotha · · Score: 4, Interesting

    A sample size of seven is too small to draw any conclusions. The radiation hypothesis makes sense, though.

  5. Re:Ionizing radiation linked to circulatory diseas by mrvan · · Score: 5, Interesting

    I agree that the sample size of 7 is rot, the 95% confidence interval around a binomial with 3/7 is 10%-82%, in other words: "we don't have a clue".
    However, neither TFA nor the /. summary actually link to the source, so here it is:

    Michael D. Delp, Jacqueline M. Charvat, Charles L. Limoli, Ruth K. Globus & Payal Ghosh, Apollo Lunar Astronauts Show Higher Cardiovascular Disease Mortality: Possible Deep Space Radiation Effects on the Vascular Endothelium, Nature Scientific Reports (open ac

    Interestingly, they do claim statistical significance on the 7 astronaut "study", but I don't have time atm to have a better look...

  6. I have another theory by Darkling-MHCN · · Score: 5, Funny

    Did they take into account the average sex life of your "I've landed on the moon" astronaut?

  7. Re: Ionizing radiation linked to circulatory disea by Rei · · Score: 4, Insightful

    Indeed, the sample size is small, but how are they supposed to get a larger sample? They did the logical followup, which is a mouse study that confirmed the (limited) human results.

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  8. Other factors? by DrXym · · Score: 2, Insightful

    Perhaps astronauts who go into deep space are feted and find themselves traveling more, eating out more, being in more smoke filled environments, stressing out in front of large audiences etc. A few days in space might not be what did it but everything that came after. Or maybe it's just a statistical blip from a small sample size.

    1. Re:Other factors? by Alomex · · Score: 3, Informative

      which is why they used lower earth orbit astronauts as a control group. (I know, I cheated, I actually read the article).

    2. Re:Other factors? by jimbolauski · · Score: 2
      You could have just RTFS

      In an attempt to test whether the higher numbers of cardiovascular deaths were simply a statistical blip or a genuine sign of the effect of traveling into deep space, the scientists exposed mice to the same type of radiation that the astronauts would have experienced. After six months, which is the equivalent of 20 human years, the mice showed damage to arteries that is known to lead to the development of cardiovascular disease in humans.

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  9. In Soviet Russia... by grungeman · · Score: 2

    ...people with heart disease are far more likely to become cosmonauts who reach deep space.

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  10. Re:Ionizing radiation linked to circulatory diseas by Anonymous Coward · · Score: 3, Interesting

    I agree that the sample size of 7 is rot, the 95% confidence interval around a binomial with 3/7 is 10%-82%

    Wrong test. The article says that "that rate of 43 percent is four to five times higher than found among astronauts who flew in low Earth orbit or who did not actually go into space". So the background rate is between 1/4 and 1/5 of 43% ... let's guess 10%. Out of 7 astronauts in deep space, we would then expect 0.7 deaths from heart disease. From a binomial distribution, the probability of getting 3 or more is 2.6%.

    So, for the hypothesis that astronauts who went to deep space have an elevated risk of heart disease compared to those who did not, we can say that it is supported, with 97.4% confidence. Still not great - it's an a posteriori hypothesis, and we don't know how wide a hypothesis space we're testing - but certainly better than you've suggested.

  11. Comparing apples to fried oranges by Sneftel · · Score: 3, Informative

    In an attempt to test whether the higher numbers of cardiovascular deaths were simply a statistical blip or a genuine sign of the effect of traveling into deep space, the scientists exposed mice to the same type of radiation that the astronauts would have experienced. After six months, which is the equivalent of 20 human years, the mice showed damage to arteries that is known to lead to the development of cardiovascular disease in humans.

    Well, no. The scientists slammed the mice with ~6-12 months' worth of radiation in ten minutes. Yeah, they probably had artery damage. Stuff like that happens when you stick a mouse in the microwave.

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  12. Re:So, what's a problem? by jabuzz · · Score: 5, Interesting

    You have to die of something. Neil Armstrong died aged 82, Buzz Aldrin is 86, and Michael Collins is 85. So all the three Apollo astronauts lived longer than the average male life expectancy for the USA, which wikipedia tells me is 76.9 years. In fact they all managed better than the average male life expectancy of the top country in the world; Japan which has one of 80.5 years.

    So while you might be at some elevated risk of dying from heart disease if you go into deep space, and the sample size is way to small to actually draw that conclusion.

    Looking at Apollo 8 through 11 so that's 12 astronauts into deep space they have *ALL* lived into their eighties with only one dying (Neil Armstrong), who also lived into his eighties.

    I can't be bothered to click through on the rest of the Apollo missions, but the only Apollo astronaut I am aware of not reaching their eighties is Ronald Evans from Apollo 17. Basically the Apollo astronauts looks to be living *VERY* full lives if you ask me.

  13. Sample size to small by sjbe · · Score: 4, Insightful

    Indeed, the sample size is small, but how are they supposed to get a larger sample?

    You don't. You just admit that the sample is to small to draw meaningful conclusions. The error bars here have to be enormous.

    They did the logical followup, which is a mouse study that confirmed the (limited) human results.

    Mice aren't humans last I checked and while mouse models are very useful you are limited in how far you can extrapolate the findings to humans. Basically this finding is something that should make scientists go "huh, that's curious - we should follow up on this once we have more data".

    1. Re:Sample size to small by AthanasiusKircher · · Score: 2

      Basically this finding is something that should make scientists go "huh, that's curious - we should follow up on this once we have more data".

      And that's actually what MOST science should be. Particularly with human studies, it's often difficult to get huge amounts of data for a decent sample, so most studies should be exploratory. Then a larger future study should be designed in such a way that it could easily DISPROVE the previous one. In that case, we'd actually make scientific progress more efficiently.

      Instead, what generally happens today:

      -- Data shows small correlation, but too little statistical power to draw firm conclusions. ("X might be related to Y.")
      -- Researchers often exaggerate significance in discussion section of paper, frequently extrapolating even more findings related to other stuff that wasn't even supported directly by data. ("X likely causes Y, and it might have something to do with A and B.")
      -- University press releases and media shout results from the rooftops. ("X is now implicated in A and B!!" Third paragraph: "Study actually showed a connection between X and Y; researchers emphasize this is preliminary finding.")
      -- Future studies cite the original without retesting. ("As shown by Jim, Sam, et al., X causes Y...") If A and B were mentioned in the abstract, you might even get references to how X "was shown" to be related to A and B.
      -- 20 years later, somebody does a study on something else, but happens to also measure X and Y. Turns out X isn't even correlated with Y at all, and the mechanism postulating a connection to A and B is based on an entirely bogus set of assumptions.

      That's why we have all these metastudies in the past few years saying, "Retesting shows 70% of findings in field X are false!"

      What we actually should recognize is that most studies (even if they seem to have a high level of statistical significance) should be regarded as "preliminary" and need verification in retesting with a more rigorous experimental design before they are accepted. It's not gonna happen in our current grant environment which rewards "innovative" and "groundbreaking" research, but that's what science should be.

      This study is precisely the kind of things that preliminary research should be about. They can't have a larger sample size yet, but they tried some testing with mice and there might be something. It's the first step in a rigorous scientific process. (Note if you actually the discussion section in this study, the authors hedge a lot and point out what they're doing is inconclusive and preliminary, though suggestive of possible effects that had previously not been measured.)

      What we DON'T need from stuff like this is headlines screaming: "Astronauts FAR MORE LIKELY TO DIE from X." That's bogus BS, and it's part of the problem.

  14. Three out of Seven? by Rob+Lister · · Score: 3, Informative
    The article states:

    They reported that three out of the seven dead Apollo astronauts...

    I count eight

    Alan Shepard
    Edgar Mitchel
    Jack Swigert
    James Irwin
    Neil Armstrong
    Pete Conrad
    Ronald Evans
    Stuart Roosa

    Pete Conrad died in a motorcycle accident. Is that justification to exclude him? With him, the rate drops to 37%. Regardless, if we wait a decade or so the sample size will be much higher.

  15. Re:So, what's a problem? by swb · · Score: 2

    This was my thought. Exploration in remote places has always been dangerous.

    Sailors risked tropical disease, sanitation-related disease, malnutrition diseases, starvation, death from dehydration.

    I'm curious what the risk rate for skin cancers is for mountaineers given that they spend increased time at high elevations with enhanced solar radiation exposure.

    Nobody is being forced to strap into a rocket and go to Mars, just like nobody is forced to skydive, climb mountains or explore any wilderness. There are people who look at the risks and decide that the exploration is worth it for them personally.

    The hard part about deep space won't be finding people willing to face these risks, it will be filtering out the few people you will actually end up sending from the vast sea of volunteers.

    And yes, to a certain extent they will be guinea pigs, but they will also help us understand the risks and develop drugs or materials or therapies to overcome them.

  16. Re:So, what's a problem? by Anonymous Coward · · Score: 5, Insightful

    Just pointing out that life expectancy at age 40, which is when these astronauts flew, is 79.9 years.

  17. Re:We won't be able to make ships with warp by NotSoHeavyD3 · · Score: 4, Informative

    Being able to achieve an erection is not more important than treating Heart Disease with little to no side effects.

    Well I guess that's ironic.(Then again someone will correct me if this isn't really an example of irony.) I mean it sounds like he's complaining about Viagra. For those that don't know the pill that gives old dudes woodies was originally developed as an anti-high blood pressure medicine. Yes, really. (Researchers noticed the side effects and somebody saw an opportunity.)

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  18. Re:So, what's a problem? by Insightfill · · Score: 4, Interesting

    Just pointing out that life expectancy at age 40, which is when these astronauts flew, is 79.9 years.

    No mod points today, so just reinforcing your statement.

    The life expectancy figures cited by grandparent are based on a starting age of "zero". A lot of kids don't make it to age five, many due to car accidents. Once you've made it to age five, the "average life expectancy" of the remaining pool has gone up quite a bit.

    As you move up the population pool age brackets, you have already lost the people who were going to bring down the average. To state otherwise brings you to the situation where you're introduced to an 85 year old man and say to him "you should have been dead five years ago!" In the case of astronauts, you're also dealing with a bunch of guys who are in relatively good shape - you've already weeded out the morbidly obese, drug addiction, etc.

    The IRS actually has tons of tables in the XLS format for figuring this sort of thing out. They're used primarily in figuring out distribution of retirement benefits over time, but have other uses.

  19. Re:So, what's a problem? by Anonymous Coward · · Score: 5, Informative

    The Apollo 1 crew didn't either, sorry to be a dick about your legitimate point.

    Aside from that, Wikipedia is your friend! https://en.wikipedia.org/wiki/List_of_Apollo_astronauts

    Pete Conrad, Apollo 12, died age 69.
    Alan Shepherd, Apollo 12, died age 74.
    James Irwin, Apollo 15, died age 61.
    Jack Swigert, Apollo 13, died age 51.
    Stu Roosa, Apollo 14 CMP, died age 61
    Ron Evans, Apollo 17 CMP, died age 56

    Evans, the youngest death, died of a heart attack but I didn't check the others.

    Neil Armstrong and Ed Mitchell died in their 80s.

    Another 19 Apollo astronauts are still alive. All of them are in their 80s with the oldest being Jim Lovell at 88.

    There were other Apollo selected astronauts if I'm not mistaken and I could have trivial facts about this wrong.

  20. Re:So, what's a problem? by Anonymous Coward · · Score: 2

    Correction, sorry. Swigert was the youngest death, respiratory failure and I presume a complication of his metastasized cancer.

  21. Re: Ionizing radiation linked to circulatory disea by Lumpy · · Score: 2

    That is easy to get a larger sample.

    Pack all the politicians in Congress and who are currently running for positions and launch them into space. We can check on them in a few years.

    Plus it will solve a HUGE problem down here at the same time.... It's a WIN-WIN!

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  22. Re:So, what's a problem? by ooloorie · · Score: 2

    If you think it's cool to ask people to go die from heart disease,

    We ask people to die from bullets in our wars. We ask people to die in car crashes for our entertainment on race tracks, and to deliver groceries. We ask people to die from experimental drugs they take as part of drug tests. We ask people to die from infections they acquire while nursing and healing the sick. We ask people to die from a lot of things.

    And you know what? People say "yes", because many things in life are worth taking risks for.

  23. Surprising side effects by sjbe · · Score: 2

    Right now Pharmaceutical Company’s only seem to be interested in manufacturing medicine that will make the big bucks, like the Blue Pill, which really serves no purpose.

    For something which you claim serves no purpose they are selling a hell of a lot of those pills. Obviously it serves a purpose for some people.

    Being able to achieve an erection is not more important than treating Heart Disease with little to no side effects.

    Funny you should say that since Viagra was originally developed for angina and hypertension. It turned out to have little effect on heart disease but they noticed the rather marked side effects and it turned out to be a financial boon for that. They did not set out to develop a drug for erectile problems, they just stumbled across one while trying to develop drugs for heart disease.

    Maybe you should acknowledge the fact that curing heart disease turns out to actually be a difficult problem to solve. Especially in light of the fact that drugs that successfully treat heart disease are hugely profitable. If you want to find a place where drug company incentives are poorly aligned with need, heart disease isn't the best place to look.