Hypercholesterolemia, Vitamin D Deficiency
Conditions
Keywords
cholesterol, LDL-cholesterol, cholecalciferol, lipids, C-reactive protein
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.
Interventions
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
Administration of placebo for 12 weeks with repeated D measurements
Sponsors
Study design
Eligibility
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
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| LDL-cholesterol | 12 weeks |
Secondary
| Measure | 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 |
Countries
United States