Clinical Trial Details
— Status: Active, not recruiting
Administrative data
NCT number |
NCT01785004 |
Other study ID # |
2012P001304 |
Secondary ID |
12GRNT11980009 |
Status |
Active, not recruiting |
Phase |
N/A
|
First received |
|
Last updated |
|
Start date |
July 2012 |
Est. completion date |
July 2022 |
Study information
Verified date |
April 2021 |
Source |
Brigham and Women's Hospital |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
The VITamin D and OmegA-3 TriaL (VITAL; NCT 01169259) is a randomized clinical trial in
20,000 U.S. men and women investigating whether taking daily dietary supplements of vitamin
D3 (2000 IU) or omega-3 fatty acids (1 gram of omega-3 fatty acids) reduces the risk of
developing cancer, heart disease, and stroke in people who do not have a prior history of
these illnesses. This ancillary study (VITAL Adiposity) is being conducted among participants
in VITAL and will examine the effect of vitamin D or fish oil on changes in body composition
and adiposity (baseline compared to 2 year, as measured by anthropometric indices, total and
regional body fat and adipokines) and assess whether changes in cardiovascular risk factors
(lipids, glucose tolerance, blood pressure) are mediated by these parameters. How achieved
25(OH)D levels are affected by body composition and body mass will also be assessed.
Description:
Observational studies suggest that low 25-hydroxyvitamin D (25(OH)D) levels are associated
with high BMI and fat mass (FM), but it is unknown whether vitamin D supplementation can
alter body composition or adiposity. Despite enthusiasm for the use of vitamin D supplements
to reduce FM, the hypothesis that vitamin D can modify adiposity remains unproven. Finding
strategies to prevent obesity is of critical public health importance due to the high
prevalence of overweight/obesity and its role in causing diabetes, hypertension,
dyslipidemia, cardiovascular disease (CVD), among others. Observational studies also link low
25(OH)D levels to CVD risk factors related to obesity, but sequestration of vitamin D in fat
tissue may be a confounding factor. The effects of vitamin D supplementation on body
composition, adiposity and CVD risk factors are best tested in a randomized clinical trial
(RCT), and according to the Institute of Medicine (IOM) 2011 report, more data from
randomized clinical trials on these outcomes are needed. Previous trials of vitamin D have
been limited by the inability to separate effects of supplemental calcium from vitamin D,
small sample size, insufficient vitamin D dose, failure to monitor 25(OH)D levels or
inadequate ascertainment of body composition. The NIH-funded VITamin D and OmegA-3 TriaL
(VITAL) (1 U01 CA138962) affords a unique and cost-effective opportunity to investigate the
effect of vitamin D on changes in body composition and to assess whether changes in CVD risk
factors are mediated, at least in part, by these parameters. VITAL is a large-scale,
randomized, primary prevention trial testing 2000 IU/d vitamin D3 (cholecalciferol) and 1
g/day omega-3 fatty acids (840 mg EPA+DHA in 1.3:1 ratio) in a 2x2 factorial design among
20,000 men and women (≥50 and ≥55 years, respectively), with mean participant follow-up of 5
years for CVD and cancer. This ancillary study will address understudied areas and two
overarching hypotheses that vitamin D supplementation (1) lowers total and regional (trunkal
and abdominal/androidal) body fat as measured by dual x-ray absorptiometry (DXA) scans,
improving biomarkers of adiposity (leptin, adiponectin) and (2) impacts CVD risk factors, at
least in part through adiposity. The investigators also seek to define how circulating
achieved 25(OH)D levels, due to supplementation, may be affected by body composition and BMI,
thus elucidating how adiposity, BMI, and body composition (total and regional) may influence
vitamin D intake needs in the population. To critically evaluate these hypotheses, the
investigators will examine a representative, randomized subcohort of 1000 racially diverse
VITAL participants (25% African American) over two years.