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Urinary Vitamin C Loss in Diabetes and Non-Diabetes

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Study AimThis study observes and compares vitamin C levels in the blood, neutrophils, and red blood cells of people with and without diabetes to understand urinary vitamin C loss.
What is being collected

Data Collection

Collected from today forward - Prospective
Who is being recruted

Urogenital Diseases
+12

+ Diabetes Mellitus
+ Endocrine System Diseases
From 18 to 65 Years
+8 Eligibility Criteria
See all eligibility criteria
How is the trial designed

Cohort

Tracking disease incidence in order to identify risk factors and understand disease progression over time.
Observational
Study Start: April 2006
See protocol details

Summary

Principal SponsorNational Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Study ContactRazi S Berman, C.R.N.P.More contacts
Last updated: December 25, 2025
Sourced from a government-validated database.Claim as a partner
Study start date: April 11, 2006Actual date on which the first participant was enrolled.

This study aims to understand how vitamin C is processed differently in people with diabetes compared to those without the condition. Research has shown that people with diabetes often have lower levels of vitamin C in their blood. Some studies also suggest they might lose more vitamin C through urine, but these findings are not clear due to various limitations in previous research. This study is important because it seeks to clarify whether the lower blood levels are due to the kidneys losing too much vitamin C, which could help in better managing vitamin C levels in diabetic patients. By including both individuals with diabetes and healthy participants, the study hopes to pinpoint the specific reasons behind these differences. Participants in the study include both people with diabetes and those without it. They will have their vitamin C levels measured in their blood, red blood cells, and urine. Some participants may stay at a clinical center for more detailed testing, which will help determine how their bodies absorb and process vitamin C. The study will also look at genetic factors that might affect vitamin C transport in the body. By comparing these measurements and potential genetic influences, researchers hope to uncover the reasons for any unusual vitamin C loss in urine among diabetic patients. This research does not involve any treatment, focusing instead on observational measurements to gather information.

Official TitleUrinary Vitamin C Loss in Subjects With and Without Diabetes 
NCT00071526
Principal SponsorNational Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Study ContactRazi S Berman, C.R.N.P.More contacts
Last updated: December 25, 2025
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details
5000 patients to be enrolledTotal number of participants that the clinical trial aims to recruit.
Cohort
These studies follow a group of individuals with common characteristics (such as a condition or birth year) over a specific period to study health outcomes or exposures.

How participants are selected
Participants are chosen using a random method, so everyone has a known and fair chance of being selected. This approach helps ensure the results reflect the broader population.
Another way to select participants is through a non-probability sample, where participants are selected without randomization, often based on availability or willingness to take part.

How information is collected
Researchers start collecting data from the present day forward, following participants over time to observe outcomes. This approach helps identify how exposures or behaviors may lead to health events in the future.

Other Ways to Collect Data
Retrospective: These studies use existing medical records or past data.
Cross-sectional: These studies collect data at one single point in time.
Others: Some studies use a mix of approaches or less common designs depending on the research goal.

Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Conditions
Criteria
Any sexBiological sex of participants that are eligible to enroll.
From 18 to 65 YearsRange of ages for which participants are eligible to join.
Healthy volunteers allowedIf individuals who are healthy and do not have the condition being studied can participate.
Conditions
Pathology
Urogenital Diseases
Diabetes Mellitus
Endocrine System Diseases
Female Urogenital Diseases and Pregnancy Complications
Metabolic Diseases
Nutritional and Metabolic Diseases
Proteinuria
Signs and Symptoms
Pathological Conditions, Signs and Symptoms
Urination Disorders
Urologic Diseases
Urological Manifestations
Glucose Metabolism Disorders
Female Urogenital Diseases
Male Urogenital Diseases
Criteria
2 inclusion criteria required to participate
Aged 18-65 years.
Either: * Have no diagnosis of diabetes: "nondiabetic controls", or * Have a diagnosis in their medical history of either Type 1 or Type 2 diabetes
6 exclusion criteria prevent from participating
other serious or chronic illness; history of serious or chronic illness; coronary artery disease, or peripheral vascular disease resulting in clinical instability
Unable or unwilling to comply with study procedures and lifestyle considerations
significant organ malfunction leading to clinical instability including liver disease, pulmonary disease, ischemic heart disease, heart failure, stroke, peripheral vascular disease, and anemia at investigator discretion
pregnancy or lactation

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Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Study Objectives
Study Objectives
Primary Objectives

Measurements of plasma, neutrophil and red blood cell vitamin c concentrations in diabetic subjects as compared to healthy controls.
Secondary Objectives

Measurements of urinary vitamin c concentrations in diabetic subjects as compared to healthy controls.

Calculate renal threshold of vitamin C in diabetic subjects as compared to healthy controls.

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.
This study has 1 location
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National Institutes of Health Clinical CenterBethesda, United StatesSee the location
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One Study Center