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The Effect of Potassium Bicarbonate on Bone and Several Physiological Systems During Immobilisation (NUC)

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ClinicalTrials.gov Identifier: NCT01509456
Recruitment Status : Completed
First Posted : January 13, 2012
Last Update Posted : March 1, 2017
Sponsor:
Collaborators:
University of Trieste
University of Aarhus
European Space Agency
Information provided by (Responsible Party):
DLR German Aerospace Center

Tracking Information
First Submitted Date  ICMJE July 4, 2011
First Posted Date  ICMJE January 13, 2012
Last Update Posted Date March 1, 2017
Study Start Date  ICMJE February 2010
Actual Primary Completion Date October 2010   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures  ICMJE
 (submitted: February 28, 2017)
The reduction of the immobilisation induced bone loss by supplementing an alkaline salt (potassium bicarbonate) [ Time Frame: 21 days of HDT- Bedrest ]
Original Primary Outcome Measures  ICMJE
 (submitted: January 10, 2012)
  • The reduction of the immobilisation induced bone loss by supplementing an alkaline salt (potassium bicarbonate) [ Time Frame: 21 days of HDT- Bedrest ]
  • The influence of KHCO3 on markers of bone formation and bone resorption [ Time Frame: 21 days of HDT- Bedrest ]
  • Determination of the effects of KHCO3- supplementation on the acid base balance [ Time Frame: 21 days of HDT- Bedrest ]
Change History Complete list of historical versions of study NCT01509456 on ClinicalTrials.gov Archive Site
Current Secondary Outcome Measures  ICMJE
 (submitted: January 10, 2012)
  • Influence of KHCO3 on bone mass, bone mineral density and bone strength [ Time Frame: 21 days of HDT- Bedrest ]
  • Determination of effects of KHCO3 on muscle strength, muscle power and muscle volume [ Time Frame: 21 days of HDT- Bedrest ]
  • Determine the effects of KHCO3 on body composition and body weight [ Time Frame: 21 days of HDT- Bedrest ]
  • Determine the effects of KHCO3 on the cardiovascular system [ Time Frame: 21 days of HDT- Bedrest ]
  • Determine the effects of KHCO3 on the neuro- vestibular system [ Time Frame: 21 days of HDT- Bedrest ]
  • Determination of effects of KHCO3 on protein and muscle turnover [ Time Frame: 21 days of HDT- Bedrest ]
Original Secondary Outcome Measures  ICMJE Same as current
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
 
Descriptive Information
Brief Title  ICMJE The Effect of Potassium Bicarbonate on Bone and Several Physiological Systems During Immobilisation
Official Title  ICMJE The Effect of Potassium Bicarbonate on Bone and the Immune System During 21 Days of 6° Head- Down- Tilt Bedrest (HDT- Bedrest)
Brief Summary

Mainly due to the absence of gravitational forces in weightlessness, astronauts suffer from an increased bone loss- negatively affecting health and vitality during a mission. The development of effective countermeasures to this loss includes many different aspects like sports but also nutrition.

Alkaline salts, abundant in fruits and vegetables, have shown to have positive effects on markers of bone turnover of postmenopausal women but also men and younger adults. With the current study the effects of a potassium bicarbonate supplementation added to a standardised, strictly controlled, definite diet of healthy, young men, should be verified within 21 days of 6°- HDT- Bedrest- the gold standard of simulating weightlessness within earthbound conditions.

Detailed Description

Astronauts in space suffer from an increased bone loss which is mainly related to the absence of gravitational forces. This increased bone reduction is accompanied by an higher concentration of calcium in urine and in this respect enhancing the risk of renal stones. Due to the fact, that bones´ regeneration does not occur rapidly even after returning to earth, astronauts face an increased risk of osteoporosis.

Nutritional factors such as a deficient intake of calcium, energy and fluid and the abundant intake of table salt exhibit additional negative effects on bone. Results of several studies consistently show the negative effects of acids on bone (increased bone loss). With respect to space missions of longer duration one big challenge is the development of countermeasures for the negative consequences of weightlessness on bone.

As not all needed experiments for the development of countermeasures can be conducted in space, simulation models of weightlessness such as 6° Head- Down- Tilt- Bedrest (HDT- Bedrest) have been implemented on earth, miming some physiological conditions of weightlessness such as unloading and immobilisation of the lower parts of the body and the fluid shift.

Alkaline salts, such as potassium bicarbonate (KHCO3), demonstrate positive effects on bone when being supplemented to postmenopausal women. Apart from the positive effects on markers of bone turnover, calcium concentration in urine could be reduced. Thus, the main aim of the present study was to reduce the immobilization induced bone resorption through an alkalizing effect of the alkaline salt KHCO3`s supplementation during Head- Down- Tilt- Bedrest (HDT- Bedrest)-a leading simulation model of weightlessness.

The crossover designed study consisted of two parts of equal length (36 days)- 7 days of adaptation, 21 days of HDT- Bedrest, 6 days recovery and 2 days of long- term follow- up. Both study parts only differed in the HDT- period, where one group of the 8 healthy, young, male participating subjects was supplemented with 90 mmol KHCO3 daily (3 times a day 30 mmol KHCO3 diluted in 200 ml tab water, supplemented together with the main meals), while the other group only received 200 ml of tab water without any supplementation (Control group).

The measurements of bone formation markers as well as bone resorption markers in blood and urine supply insight into the influences of the supplementation on bone metabolism while blood gas analysis together with the pH- values of the 24h- urine point out the alkalising effects of KHCO3. Further physiological systems like protein and muscle metabolism, body weight and body composition, circulation and the neuro- vestibular system are simultaneously under investigation.

Study Type  ICMJE Interventional
Study Phase  ICMJE Not Applicable
Study Design  ICMJE Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Condition  ICMJE
  • Bone Diseases, Metabolic
  • Acid-Base Imbalance
  • Muscular Atrophy
  • Sprains and Strains
  • Protein Metabolism
  • Body Weight Changes
  • Cardiovascular Abnormalities
Intervention  ICMJE Dietary Supplement: Potassium Bicarbonate
90 mmol daily, effervescent tablets 30 mmol diluted in 200 ml tab water supplemented three times a day together with the main meals for 21 days of HDT- bedrest
Study Arms  ICMJE
  • Active Comparator: Potassium Bicarbonate
    Intervention: Dietary Supplement: Potassium Bicarbonate
  • No Intervention: Control
Publications * Frings-Meuthen P, Bernhardt G, Buehlmeier J, Baecker N, May F, Heer M. The negative effect of unloading exceeds the bone-sparing effect of alkaline supplementation: a bed rest study. Osteoporos Int. 2019 Feb;30(2):431-439. doi: 10.1007/s00198-018-4703-6. Epub 2018 Sep 25.

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruitment Information
Recruitment Status  ICMJE Completed
Actual Enrollment  ICMJE
 (submitted: January 10, 2012)
8
Original Actual Enrollment  ICMJE Same as current
Actual Study Completion Date  ICMJE October 2010
Actual Primary Completion Date October 2010   (Final data collection date for primary outcome measure)
Eligibility Criteria  ICMJE

Inclusion Criteria:

  • healthy male subjects
  • age: 20- 45
  • weight 65- 85 kg
  • height: 158- 190 cm
  • BMI 20- 26 kg/m2
  • no high performance sports
  • non- smoking (minimum 6 months prior to study start)
  • willing to complete both parts of the study
  • presentation of social security and criminal record
  • successful completion of medical and psychological screening
  • signed informed consent

Exclusion Criteria:

  • drugs- and alcohol abuse
  • antiinflammatory drugs taken during the study
  • vegetarianism, veganism
  • migraine
  • psychical illness in the past
  • claustrophobia
  • hiatal hernia
  • gastroesophageal reflux
  • diabetes mellitus
  • Rheumatic disease
  • muscle or joint disease
  • disc prolapse
  • orthostatic intolerance
  • Hyperlipidaemia
  • renal disease
  • thyroid dysfunction
  • hyperhomocysteinaemia
  • hyper-/hypouremia
  • hyper-/hypocalcemia
  • anaemia
  • hypoferremia
  • Vitamin D deficiency
  • deviation of blood gases from normal values (pH 7,38 - 7,42; pO2 79 - 98 mmHg; pCO2 34 - 45 mmHg; HCO3 20 - 28 mmol/l; Base excess ± 2 mmol/l)
  • risk of thrombosis
  • chronic back pain
  • bone fracture within one year prior to study start
  • bone mineral density 1,5 SD ≤ t-Score
  • metal implants or other osteosynthesis material
  • subject within another clinical trial within 2 months prior to study start
  • any other status which according to the apprehension of the principal investigator leads to the exclusion of the subject
Sex/Gender  ICMJE
Sexes Eligible for Study: Male
Ages  ICMJE 20 Years to 45 Years   (Adult)
Accepts Healthy Volunteers  ICMJE Yes
Contacts  ICMJE Contact information is only displayed when the study is recruiting subjects
Listed Location Countries  ICMJE Germany
Removed Location Countries  
 
Administrative Information
NCT Number  ICMJE NCT01509456
Other Study ID Numbers  ICMJE AO-2004-068 (MAP)
Has Data Monitoring Committee No
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement  ICMJE Not Provided
Responsible Party DLR German Aerospace Center
Study Sponsor  ICMJE DLR German Aerospace Center
Collaborators  ICMJE
  • University of Trieste
  • University of Aarhus
  • European Space Agency
Investigators  ICMJE
Principal Investigator: Francisca May, Dr. German Aerospace Centre, Institute of Aerospace Medicine (DLR)
PRS Account DLR German Aerospace Center
Verification Date February 2017

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP