Study of Calcium Metabolism in Teenage Girls With Type 1 Diabetes

Study Overview
=================
Brief Summary
-----------------
The proposed pilot study will enroll 33 adolescent females with type 1 diabetes for the assessment of whole body calcium metabolism using dual stable calcium isotopes. This is the state of the art technique for assessing calcium metabolism in the body and has been used in both healthy and diseased pediatric populations.

Official Title
-----------------
Assessment of Calcium Metabolism in Adolescent Girls With Type 1 Diabetes

Conditions
-----------------
Diabetes Mellitus, Type 1

Intervention / Treatment
-----------------
* Diagnostic Test: calcium isotope analysis


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Diagnosis of T1D of at least three years duration Female sex Age between 9-18 years Parental/guardian consent and participant assent BMI <99th percentile Exclusion Criteria: History of metabolic bone disease, chronic renal disease, hepatic disease, celiac, or other malabsorptive disease History of any proton-pump inhibitor use within a 6 month period prior to enrollment History of oral or inhaled corticosteroid use for ≥ 5 consecutive days within a 6 month period prior to enrollment Pregnant or lactating females Parents/guardians or participants who, in the opinion of the Investigator, may be non-compliant with study schedules or procedures.

Ages Eligible for Study
-----------------
Minimum Age: 9 Years
Maximum Age: 18 Years

Sexes Eligible for Study
-----------------
Female

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Girls with type 1 diabetes<br> | Diagnostic Test: calcium isotope analysis<br>* A dual stable calcium isotope method will be used to determine fractional calcium absorption. Two stable calcium isotopes will be administered to participants in order to determine fractional calcium absorption. 7 mg of 44Ca will be administered orally in 60 mL of liquid at the start of the study. 2 mg of 42Ca will then be administered intravenously. 24 hour urine collection will begin immediately following oral tracer administration for the assessment of urinary calcium excretion. The enrichment of 44Ca and 42Ca in urine will be determined by magnetic sector thermal ionization mass spectrometry. The isotopic ratios of 44Ca and 42Ca to 48Ca (another naturally occurring calcium isotope present in the human body) will be calculated (42Ca/48Ca and 44Ca/48Ca). The relative fraction of the oral to intravenously administered isotope in the 24 hour urine sample [(42Ca/48Ca) / (44Ca/48Ca)] is the fractional calcium absorption.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| fractional calcium absorption | Mass spectroscopy was performed using urine to measure the stable calcium isotope. Percent dietary calcium absorption was calculated as the ratio of the cumulative recovery of 44Ca (oral tracer) to the cumulative recovery of 42Ca (IV tracer) in the 24-hour urine sample. | 24 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Estimated calcium retention | Gastrointestinal calcium absorption minus the total of urine calcium excretion and estimated stool calcium excretion. | 24 hours |