<clinical_study>
  <!-- This xml conforms to an XML Schema at:
    https://clinicaltrials.gov/ct2/html/images/info/public.xsd -->
  <required_header>
    <download_date>ClinicalTrials.gov processed this data on September 20, 2023</download_date>
    <link_text>Link to the current ClinicalTrials.gov record.</link_text>
    <url>https://clinicaltrials.gov/ct2/show/NCT01713634</url>
  </required_header>
  <id_info>
    <org_study_id>Pro0225</org_study_id>
    <nct_id>NCT01713634</nct_id>
  </id_info>
  <brief_title>Dietary Intake Modifications to Protect Against Changes in Bone Metabolism</brief_title>
  <acronym>ProK</acronym>
  <official_title>Dietary Intake Can Predict and Protect Against Changes in Bone Metabolism During Spaceflight and Recovery</official_title>
  <sponsors>
    <lead_sponsor>
      <agency>National Aeronautics and Space Administration (NASA)</agency>
      <agency_class>U.S. Fed</agency_class>
    </lead_sponsor>
  </sponsors>
  <source>National Aeronautics and Space Administration (NASA)</source>
  <oversight_info>
    <has_dmc>No</has_dmc>
  </oversight_info>
  <brief_summary>
    <textblock>
      Bone loss is not only a well-documented effect of spaceflight on astronauts, but also a&#xD;
      condition that affects millions of men and women on Earth each year. Many countermeasures to&#xD;
      bone loss have been proposed, and many have been evaluated to some degree. To date, those&#xD;
      showing potential have focused on either exercise or pharmacological interventions, but none&#xD;
      have targeted dietary intake alone as a factor to predict or minimize bone loss during&#xD;
      spaceflight. The investigators proposed to document how the ratio of acid precursors to base&#xD;
      precursors in the diet is related to directional changes in markers of bone resorption and&#xD;
      formation during flight and recovery from flight. There is a high likelihood for success in&#xD;
      predicting the extent of bone loss from dietary intake patterns of astronauts during&#xD;
      spaceflight, given that this concept is strongly anchored in data obtained from ground-based&#xD;
      experiments in our laboratory and others. The notion of manipulating diet to minimize bone&#xD;
      loss could also have significant social and economic impacts for NASA and for the general&#xD;
      public - especially given the increasing trends for diets that are high in animal protein and&#xD;
      low in fruits and vegetables. The results of the proposed experiments will lead to&#xD;
      development of a dietary countermeasure for bone loss consisting of a balanced diet with no&#xD;
      associated risks for side effects that might be present with pharmaceuticals or supplements,&#xD;
      no requirement for payload mass, and no additional crew time necessary during flight.&#xD;
    </textblock>
  </brief_summary>
  <overall_status>Completed</overall_status>
  <start_date>January 2009</start_date>
  <completion_date type="Actual">November 2015</completion_date>
  <primary_completion_date type="Actual">November 2015</primary_completion_date>
  <phase>N/A</phase>
  <study_type>Interventional</study_type>
  <has_expanded_access>No</has_expanded_access>
  <study_design_info>
    <allocation>Randomized</allocation>
    <intervention_model>Crossover Assignment</intervention_model>
    <primary_purpose>Prevention</primary_purpose>
    <masking>None (Open Label)</masking>
  </study_design_info>
  <primary_outcome>
    <measure>Change in urinary n-telopeptide after 15 days of space flight compared to preflight</measure>
    <time_frame>15 days</time_frame>
    <description>24-h NTX will be used as an indicator of bone resorption</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Change in urinary n-telopeptide after 30 days of space flight compared to preflight</measure>
    <time_frame>30 days</time_frame>
  </primary_outcome>
  <primary_outcome>
    <measure>Change in urinary n-telopeptide after 60 days of space flight compared to preflight</measure>
    <time_frame>60 days</time_frame>
  </primary_outcome>
  <primary_outcome>
    <measure>Change in urinary n-telopeptide after 120 days of space flight compared to preflight</measure>
    <time_frame>120 days</time_frame>
  </primary_outcome>
  <primary_outcome>
    <measure>Change in urinary n-telopeptide after 180 days of space flight compared to preflight</measure>
    <time_frame>180 days</time_frame>
  </primary_outcome>
  <primary_outcome>
    <measure>Change in urinary calcium after 15 days of space flight compared to preflight</measure>
    <time_frame>15 days</time_frame>
  </primary_outcome>
  <primary_outcome>
    <measure>Change in urinary calcium after 60 days of space flight compared to preflight</measure>
    <time_frame>60 days</time_frame>
  </primary_outcome>
  <primary_outcome>
    <measure>Change in urinary calcium after 120 days of space flight compared to preflight</measure>
    <time_frame>120 days</time_frame>
  </primary_outcome>
  <primary_outcome>
    <measure>Change in urinary calcium after 180 days of space flight compared to preflight</measure>
    <time_frame>180 days</time_frame>
  </primary_outcome>
  <secondary_outcome>
    <measure>Change in urinary calcium after 30 days of space flight compared to preflight</measure>
    <time_frame>30 days</time_frame>
    <description>24-h urinary calcium</description>
  </secondary_outcome>
  <number_of_arms>2</number_of_arms>
  <enrollment type="Actual">17</enrollment>
  <condition>Bone Resorption</condition>
  <arm_group>
    <arm_group_label>Low Apro/K Diet</arm_group_label>
    <arm_group_type>Experimental</arm_group_type>
    <description>Subjects consume a prescribed diet for 4 days with a low ratio of animal protein to potassium (0.3-0.6 g/mEq).</description>
  </arm_group>
  <arm_group>
    <arm_group_label>High Apro/K Diet</arm_group_label>
    <arm_group_type>Experimental</arm_group_type>
    <description>Subjects consume a prescribed diet that has a high ratio of animal protein to potassium (1.0-1.3 g/mEq) for 4 days.</description>
  </arm_group>
  <intervention>
    <intervention_type>Other</intervention_type>
    <intervention_name>Preflight</intervention_name>
    <description>4-d controlled diet sessions will occur twice before flight.</description>
    <arm_group_label>High Apro/K Diet</arm_group_label>
    <arm_group_label>Low Apro/K Diet</arm_group_label>
  </intervention>
  <intervention>
    <intervention_type>Other</intervention_type>
    <intervention_name>In-flight</intervention_name>
    <description>4-d controlled diet sessions will take place on flight days 15, 60, 120, and 180. Flight day 30 will only be monitored intakes (subject consume nominal intake)</description>
    <arm_group_label>High Apro/K Diet</arm_group_label>
    <arm_group_label>Low Apro/K Diet</arm_group_label>
  </intervention>
  <eligibility>
    <criteria>
      <textblock>
        Inclusion Criteria:&#xD;
&#xD;
          -  Astronauts flying on long-duration (3-6 months) spaceflights&#xD;
&#xD;
        Exclusion Criteria:&#xD;
&#xD;
          -  Non-astronauts&#xD;
      </textblock>
    </criteria>
    <gender>All</gender>
    <minimum_age>N/A</minimum_age>
    <maximum_age>N/A</maximum_age>
    <healthy_volunteers>Accepts Healthy Volunteers</healthy_volunteers>
  </eligibility>
  <overall_official>
    <last_name>Scott M Smith, PhD</last_name>
    <role>Principal Investigator</role>
    <affiliation>National Aeronautics and Space Administration (NASA)</affiliation>
  </overall_official>
  <location>
    <facility>
      <name>Johnson Space Center</name>
      <address>
        <city>Houston</city>
        <state>Texas</state>
        <zip>77058</zip>
        <country>United States</country>
      </address>
    </facility>
  </location>
  <location_countries>
    <country>United States</country>
  </location_countries>
  <reference>
    <citation>Zwart SR, Hargens AR, Smith SM. The ratio of animal protein intake to potassium intake is a predictor of bone resorption in space flight analogues and in ambulatory subjects. Am J Clin Nutr. 2004 Oct;80(4):1058-65. doi: 10.1093/ajcn/80.4.1058.</citation>
    <PMID>15447920</PMID>
  </reference>
  <reference>
    <citation>Zwart SR, Davis-Street JE, Paddon-Jones D, Ferrando AA, Wolfe RR, Smith SM. Amino acid supplementation alters bone metabolism during simulated weightlessness. J Appl Physiol (1985). 2005 Jul;99(1):134-40. doi: 10.1152/japplphysiol.01406.2004. Epub 2005 Feb 3. Erratum In: J Appl Physiol (1985). 2013 Sep;115(6):950.</citation>
    <PMID>15691900</PMID>
  </reference>
  <verification_date>November 2015</verification_date>
  <study_first_submitted>October 19, 2012</study_first_submitted>
  <study_first_submitted_qc>October 24, 2012</study_first_submitted_qc>
  <study_first_posted type="Estimate">October 25, 2012</study_first_posted>
  <last_update_submitted>November 13, 2015</last_update_submitted>
  <last_update_submitted_qc>November 13, 2015</last_update_submitted_qc>
  <last_update_posted type="Estimate">November 16, 2015</last_update_posted>
  <responsible_party>
    <responsible_party_type>Principal Investigator</responsible_party_type>
    <investigator_affiliation>National Aeronautics and Space Administration (NASA)</investigator_affiliation>
    <investigator_full_name>Scott M. Smith</investigator_full_name>
    <investigator_title>Manager for Nutritional Biochemistry</investigator_title>
  </responsible_party>
  <keyword>Bone resorption</keyword>
  <keyword>Diet</keyword>
  <condition_browse>
    <!-- CAUTION:  The following MeSH terms are assigned with an imperfect algorithm            -->
    <mesh_term>Bone Resorption</mesh_term>
  </condition_browse>
  <!-- Results have not yet been posted for this study                                          -->
</clinical_study>


download date: ClinicalTrials.gov processed this data on September 20, 2023
link text: Link to the current ClinicalTrials.gov record.
url: https://clinicaltrials.gov/ct2/show/NCT01713634
org study id: Pro0225
nct id: NCT01713634
lead sponsor: 
has dmc: No
Bone loss is not only a well-documented effect of spaceflight on astronauts, but also a
      condition that affects millions of men and women on Earth each year. Many countermeasures to
      bone loss have been proposed, and many have been evaluated to some degree. To date, those
      showing potential have focused on either exercise or pharmacological interventions, but none
      have targeted dietary intake alone as a factor to predict or minimize bone loss during
      spaceflight. The investigators proposed to document how the ratio of acid precursors to base
      precursors in the diet is related to directional changes in markers of bone resorption and
      formation during flight and recovery from flight. There is a high likelihood for success in
      predicting the extent of bone loss from dietary intake patterns of astronauts during
      spaceflight, given that this concept is strongly anchored in data obtained from ground-based
      experiments in our laboratory and others. The notion of manipulating diet to minimize bone
      loss could also have significant social and economic impacts for NASA and for the general
      public - especially given the increasing trends for diets that are high in animal protein and
      low in fruits and vegetables. The results of the proposed experiments will lead to
      development of a dietary countermeasure for bone loss consisting of a balanced diet with no
      associated risks for side effects that might be present with pharmaceuticals or supplements,
      no requirement for payload mass, and no additional crew time necessary during flight.
allocation: Randomized
intervention model: Crossover Assignment
primary purpose: Prevention
masking: None (Open Label)
measure: Change in urinary n-telopeptide after 15 days of space flight compared to preflight
time frame: 15 days
description: 24-h NTX will be used as an indicator of bone resorption
measure: Change in urinary n-telopeptide after 30 days of space flight compared to preflight
time frame: 30 days
measure: Change in urinary n-telopeptide after 60 days of space flight compared to preflight
time frame: 60 days
measure: Change in urinary n-telopeptide after 120 days of space flight compared to preflight
time frame: 120 days
measure: Change in urinary n-telopeptide after 180 days of space flight compared to preflight
time frame: 180 days
measure: Change in urinary calcium after 15 days of space flight compared to preflight
time frame: 15 days
measure: Change in urinary calcium after 60 days of space flight compared to preflight
time frame: 60 days
measure: Change in urinary calcium after 120 days of space flight compared to preflight
time frame: 120 days
measure: Change in urinary calcium after 180 days of space flight compared to preflight
time frame: 180 days
measure: Change in urinary calcium after 30 days of space flight compared to preflight
time frame: 30 days
description: 24-h urinary calcium
arm group label: Low Apro/K Diet
arm group type: Experimental
description: Subjects consume a prescribed diet for 4 days with a low ratio of animal protein to potassium (0.3-0.6 g/mEq).
arm group label: High Apro/K Diet
arm group type: Experimental
description: Subjects consume a prescribed diet that has a high ratio of animal protein to potassium (1.0-1.3 g/mEq) for 4 days.
intervention type: Other
intervention name: Preflight
description: 4-d controlled diet sessions will occur twice before flight.
arm group label: High Apro/K Diet
arm group label: Low Apro/K Diet
intervention type: Other
intervention name: In-flight
description: 4-d controlled diet sessions will take place on flight days 15, 60, 120, and 180. Flight day 30 will only be monitored intakes (subject consume nominal intake)
arm group label: High Apro/K Diet
arm group label: Low Apro/K Diet
criteria: 
gender: All
minimum age: N/A
maximum age: N/A
healthy volunteers: Accepts Healthy Volunteers
last name: Scott M Smith, PhD
role: Principal Investigator
affiliation: National Aeronautics and Space Administration (NASA)
facility: 
country: United States
citation: Zwart SR, Hargens AR, Smith SM. The ratio of animal protein intake to potassium intake is a predictor of bone resorption in space flight analogues and in ambulatory subjects. Am J Clin Nutr. 2004 Oct;80(4):1058-65. doi: 10.1093/ajcn/80.4.1058.
PMID: 15447920
citation: Zwart SR, Davis-Street JE, Paddon-Jones D, Ferrando AA, Wolfe RR, Smith SM. Amino acid supplementation alters bone metabolism during simulated weightlessness. J Appl Physiol (1985). 2005 Jul;99(1):134-40. doi: 10.1152/japplphysiol.01406.2004. Epub 2005 Feb 3. Erratum In: J Appl Physiol (1985). 2013 Sep;115(6):950.
PMID: 15691900
responsible party type: Principal Investigator
investigator affiliation: National Aeronautics and Space Administration (NASA)
investigator full name: Scott M. Smith
investigator title: Manager for Nutritional Biochemistry
mesh term: Bone Resorption