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
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.
- Any medically stable person able to swallow pills
- Inadequate vitamin D status at screening visit
- 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
- Malignancy under active treatment
- Feeding tube
- Intestinal bypass surgery
- Inability to swallow tablets
Janice B. Schwartz, MD,FACC,FAHA
Jewish Home, University of California, San Francisco