Whitson P A, Pietrzyk R A, Sams C F
NASA-Johnson Space Center, Astronaut Office, Houston, TX 77058, USA.
Aviat Space Environ Med. 2001 Apr;72(4):368-72.
Urine composition in astronauts during and immediately after spaceflight changes in ways that increase the renal stone-forming potential for calcium oxalate, calcium phosphate, and uric acid saturation. We examined the effect of urine volume on the risk of renal stone formation in 356 astronauts.
Renal stone-forming risk was evaluated from 24-h urine samples collected from astronauts before and after 4- to 17-d Space Shuttle flights. Urinary chemistries were performed and the relative supersaturations of calcium oxalate, brushite, sodium urate, struvite, and uric acid saturation were calculated from the biochemical results.
Urinary supersaturation levels of stone-forming salts were inversely related to urinary output both before and after spaceflight. Urine volume > 2 L x d(-1) reduced the risk of renal-stone development without affecting urinary citrate concentrations as compared with the increased risk observed in those astronauts who excreted urine volumes < L x d(-1).
Results from this study indicate that increasing daily urinary output alone is an effective countermeasure to reduce the renal stone-forming risk immediately after spaceflight. However, increasing urinary output during flight may not be entirely effective in minimizing the potential risk of renal stone formation due to the changes in the urine chemistry in astronauts exposed to microgravity.
urine volume, spaceflight, renal calculi.
在太空飞行期间及刚结束后，宇航员的尿液成分会发生变化，从而增加草酸钙、磷酸钙和尿酸饱和度形成肾结石的可能性。我们研究了356名宇航员的尿量对肾结石形成风险的影响。
通过收集宇航员在4至17天航天飞机飞行前后的24小时尿液样本，评估肾结石形成风险。进行尿液化学分析，并根据生化结果计算草酸钙、透钙磷石、尿酸钠、鸟粪石和尿酸饱和度的相对过饱和度。
在太空飞行前后，形成结石的盐类的尿液过饱和水平均与尿量呈负相关。与尿量<1L×d⁻¹的宇航员中观察到的风险增加相比，尿量>2L×d⁻¹可降低肾结石发生风险，且不影响尿枸橼酸盐浓度。
本研究结果表明，仅增加每日尿量是降低太空飞行后立即形成肾结石风险的有效对策。然而，由于暴露于微重力环境下的宇航员尿液化学成分发生变化，飞行期间增加尿量可能无法完全有效降低肾结石形成的潜在风险。
尿量；太空飞行；肾结石
