Hypertension, Obesity, Vitamin D Deficiency
Conditions
Keywords
Obesity, Renin Angiotensin System, Vitamin D deficiency, Hypertension
Brief summary
Hypothesis: Vitamin D supplementation lower renin-angiotensin system activity in obesity. Specific Aim: To investigate whether Vitamin D supplementation in obesity improves the vascular sensitivity to angiotensin II.
Detailed description
Vitamin D deficiency and obesity are international epidemics that have both been associated with increased activity of the renin-angiotensin system (RAS). Because increased RAS activity is associated with cardiovascular disease, interventions to lower RAS will have favorable public health impacts. This study aims to evaluate whether the supplementation of Vitamin D in obese subjects will lower local tissue RAS activity. RAS activity will be evaluated by cross-sectional measurement of RAS components and by quantifying the vascular response to an infusion of angiotensin II. Subjects will be studied while Vitamin D deficient, and will return for repeat study following Vitamin D supplementation, for comparison.
Interventions
DIETARY_SUPPLEMENTVitamin D (cholecalciferol)
cholecalciferol 15,000 IU daily for 30 days
Sponsors
Brigham and Women's Hospital
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
OTHER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 64 Years
Healthy volunteers
No
Inclusion criteria
* age \< 65, * Cr \< 1.6, * 25-hydroxyvitamin D \< 25 ng/mL, * BMI \> 30 kg/m2, * stage I hypertension.
Exclusion criteria
* diabetes, * coronary heart disease, * heart failure, * renal failure, * liver failure, * hyperparathyroidism, * granulomatous disease.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| The Change in the Mean Arterial Blood Pressure in Response to an Infusion of Angiotensin II | baseline and 1 month following vitamin D3 therapy |
Secondary
| Measure | Time frame |
|---|---|
| The Change in Renal Blood Flow in Response to an Infusion of Angiotensin II | baseline and 1 month following vitamin D3 therapy |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Vitamin D3 This was a single-arm open-label study where participants received 15,000IU of vitamin D3 daily for 4 weeks. | 14 |
| Total | 14 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Overall Study | Physician Decision | 12 |
Baseline characteristics
| Characteristic | Vitamin D3 |
|---|---|
| Age, Continuous | 49.6 years STANDARD_DEVIATION 9.2 |
| Pre-Intervention 25-hydroxyvitamin D3 | 18.20 ng/mL STANDARD_DEVIATION 6.76 |
| Pre-Intervention Mean Arterial Pressure | 105.6 mmHg STANDARD_DEVIATION 7.22 |
| Pre-Intervention Parathyroid hormone concentration | 46.36 pg/mL STANDARD_DEVIATION 16.09 |
| Pre-Intervention Serum calcium concentration | 8.94 mg/dL STANDARD_DEVIATION 0.3 |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants |
| Race (NIH/OMB) Black or African American | 10 Participants |
| Race (NIH/OMB) More than one race | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) White | 4 Participants |
| Region of Enrollment United States | 14 Participants |
| Sex: Female, Male Female | 9 Participants |
| Sex: Female, Male Male | 5 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | — / — |
| other Total, other adverse events | 0 / 26 |
| serious Total, serious adverse events | 0 / 26 |
Outcome results
Primary
The Change in the Mean Arterial Blood Pressure in Response to an Infusion of Angiotensin II
Time frame: baseline and 1 month following vitamin D3 therapy
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Vitamin D3 | The Change in the Mean Arterial Blood Pressure in Response to an Infusion of Angiotensin II | 1.97 mmHg | Standard Deviation 5.14 |
Comparison: A repeated measures regression analysis model was used to examine the effect of vitamin D3 therapy on the mean arterial pressure (mean of five measurements at each time point) before and during angiotensin II infusions, before and after vitamin D3 therapy.p-value: <0.05Mixed Models Analysis
Secondary
The Change in Renal Blood Flow in Response to an Infusion of Angiotensin II
Time frame: baseline and 1 month following vitamin D3 therapy
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Vitamin D3 | The Change in Renal Blood Flow in Response to an Infusion of Angiotensin II | -20.0 mL/min/1.72m2 | Standard Deviation 40.7 |
Comparison: A repeated measures regression analysis model was used to examine the effect of vitamin D3 therapy on the renal plasma flow (mean of three measurements at each time point) before and during angiotensin II infusions, before and after vitamin D3 therapy.p-value: <0.01Mixed Models Analysis