Renal stone formation among astronauts.
BACKGROUND
With the continued construction of the International Space Station, humans are living longer in the microgravity environment of space. However, many questions still exist as to the physiological effects of spaceflight on the human body. Bone loss, cardiovascular changes, and muscle atrophy are well-documented health risks to humans during spaceflight. Another potential serious health complication is the development of renal stones. The development of a renal stone may not only impact the health of the crewmember, but also the success of the mission.


METHODS
A retrospective analysis of astronaut data from 24-h urine samples collected prior to launch and immediately after landing was performed. Urine characteristics associated with renal stone formation were analyzed and the relative injury supersaturations of stone-forming constituents calculated.


RESULTS
In the current study, previously collected data to identify urinary factors associated with renal stone formation demonstrated an increased risk in astronauts who had actually formed a renal stone. Increased urinary supersaturation of the stone-forming salts was observed in those astronauts who formed renal stones. Similar changes in urinary supersaturation were noted among many astronauts after landing, indicating an increased postflight risk for stone formation.


CONCLUSIONS
An assessment program should be undertaken to identify and evaluate astronauts with elevated risk factors prior to flight and immediately following landing. Individualized recommendations can be prescribed to astronauts and may include dietary changes, increased fluid intake, or medications to minimize the risk of stone formation.
Pietrzyk
Robert A
RA
Wyle Laboratories , Houston, TX, USA.
Jones
Jeffrey A
JA
Sams
Clarence F
CF
Whitson
Peggy A
PA
D000337:Aerospace Medicine; D018480:Astronauts; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000209:etiology / Q000517:prevention & control* / Q000652:urine; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D013026:Space Flight; D014481:United States; D014893:Weightlessness / Q000009:adverse effects*