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Effect of Sodium Intake on Calcium Retention in Girls

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ClinicalTrials.gov Identifier: NCT01564238
Recruitment Status : Completed
First Posted : March 27, 2012
Last Update Posted : May 9, 2018
Sponsor:
Collaborator:
Institute of Child Health
Information provided by (Responsible Party):
Berdine Martin, Purdue University

Brief Summary:
Optimal calcium retention is important for building bone mass within the genetic potential, a key to reducing risk of osteoporosis later in life. Calcium retention is high during the rapid growth period. The investigators know that urinary calcium is affected by sodium intake but the investigators do not know the effects of sodium intake during the growth spurt or the differences in calcium retention between blacks and whites. Our hypothesis was that a high dietary sodium increases the calcium intakes required for optimal calcium retention in both black and white adolescent girls. The investigators tested calcium retention while girls consumed a low and high sodium diet during three week periods. The subjects were housed in a Purdue fraternity house during the summer and they were supervised at all times by trained staff. During the summer of 1999, subjects consumed diets with 2 levels of dietary Na+ with a fixed diet low in calcium. On the next summer, they switched to a high calcium diet. Subjects collected fecal and urine daily for 20 days. Other measurements included daily body weight, blood pressure every other day, blood sample at the end of each session. Baseline measures included bone mass, self-assessment of pubertal development, a physical examination and diet history.

Condition or disease Intervention/treatment Phase
Osteoporosis Other: Low Na diet (1.3 g/d) Other: High sodium diet (3.8 g/d) Not Applicable

Detailed Description:

Optimal calcium retention is a prerequisite for building maximal peak bone mass within the genetic potential, a key to reducing risk of osteoporosis later in life. The investigators have determined that maximal calcium retention averages 423 mg/day during the period of rapid skeletal accretion in white girls at a mean dietary calcium intake of 1300 mg/d. Urinary calcium explains more than 50% of the variance in calcium retention. However, urinary sodium (i.e. sodium intake)is a major determinant of urinary calcium excretion and the effect of sodium intake on maximal calcium retention is not known. Nor is its effect known in black adolescents who have higher bone density and lower calcium excretion than white adolescents.

The primary aim was to test the hypothesis that high dietary sodium increases the calcium intakes required for optimal calcium retention in both black and white adolescent girls. Calcium retention was measured at two levels of dietary sodium in a randomized crossover design on one of two levels of dietary calcium intake in black and white adolescent girls during three week metabolic periods. The investigators hypothesized that the mechanisms which regulate sodium reabsorption in the renal tubules also regulate calcium retention. Increased incidence of hypertension in blacks compared to whites has been attributed to increased sodium retention. Sodium intake induced changes in calcium and sodium retention in both races were related to changes in sodium handling (plasma renin activity, serum aldosterone, and salt sensitivity) and calcium regulating hormones, biomarkers of bone turnover and bone mass.

The subjects were resident in a Purdue fraternity house, which was transformed during the summer into a metabolic unit. Subjects were supervised at all times by trained staff. The balance study was divided into 2 sessions of 3 weeks each during the summer of 1999 and 2000, with 2 levels of dietary Na+ during each summer. During the summer of 1999 subjects consumed a low calcium diet while in the summer of 2000 subjects consumed a high calcium diet. The Na+ intake periods were separated by a 2-week period, in which subjects were free to consume self-selected diets. Subjects collected fecal and urine daily for 20 days. Other measurements included daily body weight, blood pressure every other day, blood sample at the end of each session. Baseline measures included bone mass, self-assessment of pubertal development, a physical examination and diet history.


Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 67 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single (Participant)
Primary Purpose: Prevention
Official Title: Effect of Sodium Intake on Calcium Retention in Black and White Adolescent Girls.
Study Start Date : January 1999
Actual Primary Completion Date : August 2000
Actual Study Completion Date : August 2000

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Calcium Osteoporosis
U.S. FDA Resources

Arm Intervention/treatment
Experimental: High calcium diets (1300 mg or higher) Other: Low Na diet (1.3 g/d)
20 day controlled feeding study (live in) providing 1.3 grams per day of sodium.
Other Names:
  • low sodium
  • sodium calcium
Other: High sodium diet (3.8 g/d)
20 day controlled feeding study (live in) providing 3.8 grams per day of sodium.
Other Names:
  • high sodium
  • sodium calcium
Experimental: Low calcium diet (800 mg/d) Other: Low Na diet (1.3 g/d)
20 day controlled feeding study (live in) providing 1.3 grams per day of sodium.
Other Names:
  • low sodium
  • sodium calcium
Other: High sodium diet (3.8 g/d)
20 day controlled feeding study (live in) providing 3.8 grams per day of sodium.
Other Names:
  • high sodium
  • sodium calcium



Primary Outcome Measures :
  1. Change in calcium retention(mg/d)due to high (4g/d) and low (1g/d) sodium intake. [ Time Frame: Up to 12 weeks ]

Secondary Outcome Measures :
  1. Potassium retention in the black and white adolescent subjects [ Time Frame: Up to 12 weeks ]
  2. Racial differences on the effects of high and low sodium intake levels on calcium intake requirements and calcium retention in adolescent girls [ Time Frame: Up to 12 weeks ]
  3. Magnesium retention in the black and white adolescent subjects [ Time Frame: Up to 12 weeks ]


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Ages Eligible for Study:   11 Years to 15 Years   (Child)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • White or black race (both parents and grandparents had to be white or black to be eligible in the study).

Exclusion Criteria:

  • < 11 or > 15 years
  • body mass index (BMI) of < 15th or > 85th percentile for age
  • history of amenorrhea, pregnancy or abortion, eating disorders, oral contraceptive or tobacco use.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01564238


Locations
United States, Indiana
Purdue University
West Lafayette, Indiana, United States, 47906
Sponsors and Collaborators
Purdue University
Institute of Child Health
Investigators
Principal Investigator: Connie M Weaver, PhD Purdue University
Study Director: Berdine R Martin, PhD Purdue University

Publications of Results:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Berdine Martin, Research Scientist, Nutrition Science, Purdue University
ClinicalTrials.gov Identifier: NCT01564238     History of Changes
Other Study ID Numbers: Camp Calcium 5-6
First Posted: March 27, 2012    Key Record Dates
Last Update Posted: May 9, 2018
Last Verified: May 2018

Keywords provided by Berdine Martin, Purdue University:
calcium retention
sodium retention

Additional relevant MeSH terms:
Osteoporosis
Bone Diseases, Metabolic
Bone Diseases
Musculoskeletal Diseases
Metabolic Diseases
Calcium, Dietary
Bone Density Conservation Agents
Physiological Effects of Drugs