Renal Stone Incidence Rate Quantification
The Challenge
Renal stones are small rock-like deposits of calcium oxalate crystals and other minerals that form in the kidneys or urinary tract. Astronauts are at an increased risk of developing a renal stone due to an increase in bone demineralization during long-duration spaceflight exploration and when exposed to reduced gravity. As bone loss occurs, the body releases excess calcium into the excretory system which may lead to an increase in the risk of renal stones. Combined with a decrease in hydration or limited diet, this could result in a serious health risk to the astronauts. An un-treated kidney stone on a long-duration mission could lead to severe pain, dysuria, nausea, or could possibly require crew evacuation and return to Earth.
The Research
The risk of formation of a renal stone during spaceflight is largely mitigated through the following:
- Pre-flight screening
- Preventative countermeasures like exercise, increasing fluid intake, and dietary recommendations
The Computational Modeling Project has developed a computational model to help quantify how available drinking water changes the risk of renal stones during missions and post-flight and to assess the effectiveness of individual and combined countermeasures.
The Progress
The Computational Modeling Project team has developed a computational biochemistry model representing CaOx crystal precipitation, growth, and agglomeration is combined with a probabilistic analysis to predict the in- and post-flight CaOx renal stone incidence risk ratio (IRR) relative to pre-flight values using astronaut 24-hour urine chemistries. Using a Monte Carlo sampling process, the model processes 1000s of random unique urine chemistries through a biochemistry model, the population balance equation renal stone growth model, and the Poisson regression to calculate the incidence rate of CaOx renal stones per person per year.
Based on this data, our simulations predict that increasing fluid-intake alone would reduce the overall risk of renal stone formation. However, if you were to combine increased fluid-intake with an additional countermeasure like exercising or a dietary supplement of Bisphosphonate, the fluid-intake could be adjusted to a lower amount and still be an effective countermeasure. This type of quantitative risk assessment can help inform the critical balance between engineering system constraints and astronaut health requirements, and act as evidence for updates to the NASA Space Flight Human System Standards [NASA-STD-3001 Volume 2 (6.3.2.1 Drinking Water Quantity)].
Acronyms
CaOx – Calcium Oxalate
PBE – Population Balance Equation
Renal Stone Gaps
What is an HRP Gap?
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please select the links below the for more information.
B7 Fluid Intake
B9 Frequency of formation
Technical Data
Prediction of renal crystalline size distributions in space using a PBE analytic model
Cardiovascular Impacts
What are the in-flight alterations in cardiac structure and function?
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Measuring VO2 inflight
What is VO2max in-flight and immediately post-flight?
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Predicting Heart Disease
Can manifestations of sub-clinical or environmentally induced cardiovascular diseases during spaceflight be predicted?
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Outcome of Medical Events
We do not know the quantified health and mission outcomes due to medical events during exploration missions.
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Doctor on Board?
We do not know how the inclusion of a physician crew medical officer quantitatively impacts medical risk during exploration missions.
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Microgravity Countermeasures
How does 1/6-g and 3/8-g influence countermeasures?
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Efficient Exercise Regimen
Develop the most efficient and effective exercise program for the maintenance of muscle function.
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Minimum Exercise Needed?
What is the minimum exercise regimen needed to maintain fitness levels for tasks?
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Exercise Hardware
Identify and validate exploration countermeasure hardware for the maintenance of muscle function.
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Time Course of Changes in Muscle
Characterize the time course of changes in muscle protein turnover, muscle mass, and function during long duration space flight.
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Bone Health Standard
A new acceptable bone health standard using an expanded surrogate for bone health needs to be defined for the flight environment.
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Osteoporosis & Fractures
What is the incidence & prevalence of early onset osteoporosis or fragility fractures due to exposure to spaceflight.
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Ocular changes
We do not know the etiological mechanisms and contributing risk factors for ocular structural and functional changes seen in-flight and post-flight.
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Medical Event Risk Metrics
We need to characterize the medical conditions that can occur during exploration missions and their relevant associated end states, management options, and the capabilities necessary to manage them (what can happen, how bad could it be, what can we do to improve it?).
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Integrated Exploration Medical System Models
We need to develop integrated exploration medical system models for the Moon and Mars.
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Cardiovascular Impacts from Weightlessness
Determine whether long-duration weightlessness induces cardiovascular structural and functional changes and/or oxidative stress & damage (OSaD)/inflammation, that can contribute to development of disease.
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Fluid Intake
Is it necessary to increase crew fluid intake and, if possible, to what extent will it mitigate stone formation?
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.
Frequency of formation
What is the frequency of post-flight stone formation; the incidence and types of stones; and the time course of stone formation? How does stone formation correlate with food intake and hydration status?
Evidence from medical records, spaceflight operations and research findings provides the basis for identifying the most significant human risks in space exploration, including physiological and performance effects from hazards such as altered gravity, radiation, hostile/closed environments, isolation and distance. Each risk is assigned to an HRP Element (divisions of human research) to identify knowledge gaps, or the critical questions that must be answered, in order to mitigate the risk. These gaps become the focus of research conducted to reduce the likelihood and consequence of risks becoming a reality. To learn more about the Risk Identification and Mitigation process and the tasks developed to reduce those risks for the program please click on the link below the gap for more information.