Effects of Vitamin D on Lipids

Study Overview
=================
Brief Summary
-----------------
The purpose of this study is to examine whether oral vitamin D supplementation in people with inadequate vitamin D concentrations will lower LDL-cholesterol and total cholesterol concentrations.

Detailed Description
-----------------
Data from previous trials suggest a protective role of vitamin D in cardiovascular disease. A recent meta-analysis of trials with at least 5 years of follow-up of vitamin D supplementation concluded that intake of vitamin D supplements may decrease total mortality, but that the relationship between baseline vitamin D status, dose of vitamin D supplements, and total mortality rates remains to be investigated. An even more recent analysis of vitamin D concentrations found that participants with vitamin D deficiency and hypertension were about twice as likely as people without hypertension and vitamin D deficiency to have a cardiovascular event during the study. The main hypothesis to be tested is that normalization of vitamin D levels will lower LDL-cholesterol and total cholesterol concentrations in people with inadequate vitamin D concentrations as determined by circulating 25-OH vitamin D. Subhypotheses are that HDL-cholesterol, triglycerides, lipoprotein(a), hs C-reactive protein and Hemoglobin A1c will not be affected, and that cyp3a-metabolized medication levels will decrease with vitamin D replacement. This is a 12-week randomized double-blind dose titration study of the effects of supplementation with 1000-2000 IU vitamin D on lipid and vitamin D concentrations. Dietary intake of vitamin D will be estimated by dietary recall questionnaire or analysis of three non-consecutive 24-hour dietary intake logs.

Official Title
-----------------
Effects of Vitamin D on Lipids

Conditions
-----------------
Hypercholesterolemia, Vitamin D Deficiency

Intervention / Treatment
-----------------
* Dietary Supplement: Vitamin D (1000 or 2000 IU/day)
* Other: Placebo


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Any medically stable person able to swallow pills Inadequate vitamin D status at screening visit Exclusion Criteria: Clinical instability of underlying disease process (e.g., recent hospitalization, change of dosages of medications within the prior two weeks, or new medications within one month) Recent transfusion Severe renal failure or dialysis Hypercalcemia Malignancy under active treatment Feeding tube Intestinal bypass surgery Inability to swallow tablets

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

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

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

Design Details

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br>Placebo administration for 12 weeks with repeated 25-OH D determinations over 12 weeks, dietary, sunshine questionnaire recording | Other: Placebo<br>* Administration of placebo for 12 weeks with repeated D measurements<br>|
| Experimental: Vitamin D<br>Vitamin D (1000 or 2000 IU/day) | Dietary Supplement: Vitamin D (1000 or 2000 IU/day)<br>* Dose titration beginning with 1000 IU/day and either remaining at 1000 IU/day for weeks 7-12 if normalized D levels at 6 weeks or increasing to 2000 IU/day for weeks 7-12 if levels not normalized at week 6<br>* Other names: cholecalciferol;|

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| LDL-cholesterol |  | 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vitamin D and metabolite concentrations with supplementation and time course of repletion in deficient or insufficient subjects |  | 12 weeks | 
| Measures of inflammatory markers |  | 12 weeks | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
cholesterol, LDL-cholesterol, cholecalciferol, lipids, C-reactive protein