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"exec" writes in with a story from Ars Technica — Apollo astronauts dying of heart disease at 4-5X the rate of counterparts:

Apollo astronauts who have ventured out of the protective magnetosphere of mother Earth appear to be dying of cardiovascular disease at a far higher rate than their counterparts—both those that have stayed grounded and those that only flew in the shielding embrace of low-Earth orbit. Though the data is slim—based on only 77 astronauts total—researchers speculate that potent ionizing radiation in deep space may be to blame. That hypothesis was backed up in follow-up mouse studies that provided evidence that similar radiation exposure led to long-lasting damage to the rodents’ blood vessels. All of the data was published Thursday in the journal Scientific Reports.

[...] In the new study, [Michael] Delp [at Florida State University] and coauthors compared health data on 42 astronauts that had traveled into space—seven of which got past the magnetosphere and to the Moon—to the medical records of 35 astronauts that were grounded for their careers. The death rate from cardiovascular disease among the Apollo lunar astronauts was a whopping 43 percent, which is around four to five times the rate seen in the non-fliers and low-fliers (nine and 11 percent, respectively).

To figure out if deep-space ionizing radiation or, perhaps, weightlessness might explain the apparent jump in cardiovascular disease deaths, the researchers turned to a mouse model. Mice were either exposed to a single dose of radiation, had their hind limbs elevated to prevent weight-bearing for two weeks, or received both treatments. The researchers then let the faux-astronaut mice recover for six to seven months, which in human terms would be about 20 years.

[Continues...]

The researchers found that the mice exposed to radiation, or both radiation and simulated weightlessness, had sustained damage to their blood vessels. Namely, the mice had impaired vasodilation, or problems expanding their blood vessels to adjust for blood pressure. This can be a precursor to heart attacks and stroke. The mice that just experience simulated weightlessness, on the other hand, seemed normal.

While the rodent data complement the findings in real astronauts, the authors were clear about the limitations of the study. “Caution must be used in drawing definitive conclusions regarding specific health risks,” they concluded. The astronaut numbers are very small for an epidemiological study, there may be other factors in the space environment that could explain the possible health effects, and the type of radiation given to the mice wasn’t exactly the same as the type astronauts experience.

Delp and his colleagues are working with NASA on follow-up studies of astronauts’ health.

-- submitted from IRC

That seems to be a very small sample from which to draw any kind of conclusion, but it does suggest that outer space may be more hazardous that we thought. How will/should this affect future manned (personed?) space flight plans? With SpaceX planning to create a Mars Colonization Transport ship, maybe they would launch a hundred or so mice on a trip around the moon for their own edification?

Other coverage:
University Herald
The Guardian .

Original Submission