Vitamin A Kinetics and Mathematical Modeling in American Women

Study Overview
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Brief Summary
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Women were given a vitamin A tracer, and blood was sampled to determine individual and group vitamin A kinetics. Data were subsequently modeled using compartmental analysis to determine effects of study length on model outcomes.

Detailed Description
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This is a longitudinal study in which American women were given an oral, stable isotope tracer of vitamin A, and blood was sampled in a staggered, serial design to determine individual and group vitamin A kinetics. Data were subsequently modeled using compartmental analysis, and study truncation analysis was performed on data to investigate the factor of study duration on resulting vitamin A kinetic models and outputs related to vitamin A metabolism.

Official Title
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Vitamin A Kinetics and Mathematical Modeling in American Women

Conditions
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Vitamin A Kinetics

Intervention / Treatment
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* Other: Vitamin A tracer


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI (18.5 - 24.9 kg/m2) Exclusion Criteria: Smoker Pregnant Trying to become pregnant Lactating Weight loss > 4.5 kg during the past 3 months. Actively trying to lose weight Inability to refrain from drinking alcohol when requested Amenorrhea Acute or chronic illness including hepatitis Current or previous history of anorexia or bulimia Concurrent participation in other studies Family member already enrolled in the study

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Vitamin A tracer<br>A stable isotope tracer of vitamin A was given orally. | Other: Vitamin A tracer<br>* A stable isotope tracer of vitamin A was given orally.<br>* Other names: 13C retinyl acetate;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total traced vitamin A mass | Total amount of endogenous vitamin A determined by mathematical model, (µmol). | Baseline through 152 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Compartmental model complexity | Required number of compartments in mathematical model needed to adequately fit data. | Baseline through 152 days | 
| Compartmental model fractional transfer coefficients | Model parameters adjusted to fit analytical data. Represents the fractional transfer from one compartment to another in the model, (pools/d, represented as L(i,j), the fraction of compartment J transferred to compartment I per day). | Baseline through 152 days | 
| Serum vitamin A half-life | Half-life of vitamin A in serum, (d). | Baseline through 152 days | 
| Vitamin A disposal rate | Daily loss or utilization of vitamin A, (µmol/d). | Baseline through 152 days | 
| Vitamin A equilibration time and partitioning | Time taken for vitamin A to equilibrate with body stores, (d). | Baseline through 152 days | 
| Vitamin A tracer partitioning | Body partitioning of tracer between serum and extravascular compartment(s), relative to total tracee mass. Calculated as a ratio of tracer-to-tracee ratio (TTR) in serum and extravascular stores, (TTR serum / TTR stores). | Baseline through 152 days | 
| Vitamin A dietary intake | Vitamin A dietary intake by food frequency questionnaire, (µg retinol activity equivalents/d). | Baseline |