---
title: Effect of Vitamin D Supplementation on Hemoglobin A1c in Patients With Uncontrolled Type 2 Diabetes Mellitus
nct_id: NCT00985361
overall_status: COMPLETED
phase: NA
sponsor: ProMedica Health System
study_type: INTERVENTIONAL
primary_condition: Type 2 Diabetes Mellitus
countries: United States
canonical_url: "https://parkinsonspathways.com/agent/trials/NCT00985361.md"
clinicaltrials_gov: "https://clinicaltrials.gov/study/NCT00985361"
ct_last_update_post_date: 2010-05-06
last_seen_at: "2026-05-12T06:17:21.385Z"
source: ClinicalTrials.gov (mirrored, no enrichment)
---
# Effect of Vitamin D Supplementation on Hemoglobin A1c in Patients With Uncontrolled Type 2 Diabetes Mellitus

**NCT ID:** [NCT00985361](https://clinicaltrials.gov/study/NCT00985361)

## Key Facts

- **Status:** COMPLETED
- **Phase:** NA
- **Study Type:** INTERVENTIONAL
- **Target Enrollment:** 37
- **Lead Sponsor:** ProMedica Health System
- **Conditions:** Type 2 Diabetes Mellitus
- **Start Date:** 2009-10
- **Completion Date:** 2010-03
- **CT.gov Last Update:** 2010-05-06

## Brief Summary

The purpose of this study is to determine if daily supplementation with 2000 International Units of Vitamin D will improve hemoglobin A1c in uncontrolled type 2 diabetics.

## Detailed Description

Vitamin D is typically understood to support musculoskeletal health when administered concomitantly with calcium. A number of recent studies suggest, however, that this important nutrient may play a significant role in many pathophysiological processes, including diabetes mellitus. With the prevalence of diabetes mellitus ever increasing, novel mechanisms for controlling blood glucose and hemoglobin A1c are being sought to help prevent the costly and debilitating complications of this chronic disease.

## Eligibility

- **Minimum age:** 21 Years
- **Maximum age:** 75 Years
- **Sex:** ALL
- **Healthy Volunteers:** No

```
Inclusion Criteria:

* Type 2 diabetes mellitus
* Hemoglobin A1c \>7% measured in the 3 months prior to randomization
* Age 21 to 75 years

Exclusion Criteria:

* Renal insufficiency (defined as CrCl \<30mL/min)
* Gestational diabetes
* Malabsorption syndrome
* Patients taking vitamin D supplements at doses \>400 international units daily
```

## Arms

- **Vitamin D 2000 international units daily** (EXPERIMENTAL)
- **Vitamin C 500mg daily** (ACTIVE_COMPARATOR)

## Interventions

- **Vitamin D3 2000 international units daily** (DIETARY_SUPPLEMENT) — Vitamin D3 2000 international unit tablets once daily for 3 months
- **Vitamin C 500mg daily** (DIETARY_SUPPLEMENT) — Vitamin C 500mg tablets once daily for 3 months

## Primary Outcomes

- **Hemoglobin A1c** _(time frame: 3 months)_

## Locations (3)

- Flower Hospital Family Medicine Residency, Sylvania, Ohio, United States
- Center for Health Services, Toledo, Ohio, United States
- Toledo Hospital Family Medicine Residency, Toledo, Ohio, United States

## Recent Field Changes (last 30 days)

- `sponsor.lead` — added _(2026-05-12)_
- `results.hasResults` — added _(2026-05-12)_
- `status.overallStatus` — added _(2026-05-12)_
- `status.primaryCompletionDate` — added _(2026-05-12)_
- `status.completionDate` — added _(2026-05-12)_
- `status.lastUpdatePostDate` — added _(2026-05-12)_
- `design.phases` — added _(2026-05-12)_
- `design.enrollmentCount` — added _(2026-05-12)_
- `eligibility.criteria` — added _(2026-05-12)_
- `eligibility.minAge` — added _(2026-05-12)_
- `eligibility.maxAge` — added _(2026-05-12)_
- `eligibility.sex` — added _(2026-05-12)_
- `outcomes.primary` — added _(2026-05-12)_
- `armsInterventions.arms` — added _(2026-05-12)_
- `armsInterventions.interventions` — added _(2026-05-12)_
- `locations.flower hospital family medicine residency|sylvania|ohio|united states` — added _(2026-05-12)_
- `locations.center for health services|toledo|ohio|united states` — added _(2026-05-12)_
- `locations.toledo hospital family medicine residency|toledo|ohio|united states` — added _(2026-05-12)_

---

*Canonical: https://parkinsonspathways.com/agent/trials/NCT00985361.md*  
*Source data (authoritative): https://clinicaltrials.gov/study/NCT00985361*  
*This page is a raw mirror with no AI summary, no editorial enrichment, and no Parkinson's-specific filtering.*