Elevated Coronary Artery Calcium Scores in Astronauts

We previously published a model of how calcium from resorbing bone can enter and persist in the circulation with consequent precipitation in coronary arteries. The model was based on chronic inflammation as the source of continued bone resorption. We asked whether other forms of resorptive bone loss such as microgravity (disuse) might also be associated with bone calcium accumulation in coronary arteries.

We analyzed a de-identified database provided by NASA consisting of 52 astronauts who had flown a space mission around two determinations of coronary artery calcium (CAC) scores at 5-yr intervals and bone density determinations in the year prior to and 10 d and 1 yr following a space mission.

We found that in 38.5% of the astronauts, their CAC scores changed between pre- and postflight, with 95% of the CAC scores increasing. These astronauts were significantly older than the 61.5% whose CAC scores did not change, although the mission length was not different between the groups. Both groups lost bone acutely but had partial recovery over the year postflight.

Due to lack of uniform sampling times, we could not correlate changes in CAC score with bone loss and would advocate for synchronous determinations of CAC and bone density pre- and postflight. Klein GL, Jupiter DC. Elevated coronary artery calcium scores in astronauts. Aerosp Med Hum Perform. 2025; 96(4):356-359.