An interventional study of Vitamin D in Vitamin d Deficiency, sponsored by University of Delaware. Completed at 1 site in United States. Open to female participants aged 18 Years to 30 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-01-24.
Sponsored by University of Delaware · Not applicable, Interventional, and Prevention
The goal of this clinical trial is to understand the effects of oral vitamin D3 supplementation on various cardiovascular risk factors in generally healthy, young adult black women who are vitamin D deficient or insufficient at baseline.
The main questions it aims to answer are:
All participants will undergo baseline testing, which includes 2 continuous weeks of objective sleep monitoring using a sleep watch, one 24-hour period of ambulatory blood pressure monitoring, and one blood vessel function testing visit. Following baseline testing, vitamin D insufficient and deficient participants will be prescribed take 5,000 IU of vitamin D3 daily for 8 continuous weeks. Participants will undergo 2-weeks of sleep monitoring again during weeks 3-4 of the supplementation period and during weeks 7-8 of the supplementation period. Additionally, 24-hour blood pressure monitoring will be performed during week 4 and week 8, and blood vessel function testing will take place at the end of week 4 and again at the end of week 8.
Researchers will assess the effect of the vitamin D3 supplementation intervention by comparing all values between baseline, week 4, and week 8 to see if there is any effect of vitamin D3 supplementation on 24-hour blood pressure, sleep duration and regularity, and blood vessel structure and function following 4 and 8 weeks of supplementation.
772 studies on the registry are indexed under Vitamin D Deficiency; 61 are open to participants now.
This study's enrollment of 22 is below the median of 77 across 564 interventional studies indexed under Vitamin D Deficiency.
Browse Vitamin D Deficiency studies →University of Delaware is the lead sponsor of 125 studies on the registry; 23 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
5,000 IU of oral vitamin D3 in white powder form, daily for 8 continuous weeks
Dietary Supplement: Vitamin D
oral vitamin D3
Change in 24-hour ambulatory systolic and diastolic blood pressure (mmHg) using an at-home ambulatory blood pressure monitor.
Participants will undergo a 24-hour period of ambulatory systolic and diastolic blood pressure (mmHg) recording to evaluate diurnal systolic and diastolic blood pressure and nocturnal systolic and diastolic blood pressure.
Time frame: Change from baseline blood pressure values at 4 weeks and 8 weeks.
Change in objectively estimated sleep duration and sleep efficiency using a Philips Actiwatch Spectrum Plus accelerometer wrist watch
Participants will undergo a two-week period of objectively estimated sleep recording using the Actiwatch. Sleep duration will be calculated as the average time spent asleep each night (hours) and sleep efficiency will be calculated as (total time asleep/total time in bed)\*100%. Changes from baseline will be compared at week 4 and week 8.
Time frame: Change from baseline sleep duration and sleep efficiency at 4 weeks and 8 weeks.
Change in serum 25(OH)D concentration
Serum 25-hydroxyvitamin D concentration will be clinically assessed via Labcorp testing services.
Time frame: Change from baseline 25(OH)D at 4 weeks and 8 weeks.
Change in brachial artery pulse wave analysis using the Sphygmocor XCEL system
Brachial systolic and diastolic blood pressure (BP) will be measured using the Sphygmocor XCEL system and central BP, augmentation index, and arterial wave reflections will be estimated via partial cuff inflation. Changes from baseline will be compared at week 4 and week 8.
Time frame: Change in pulse wave analysis measures from baseline, week 4, and week 8
Change in carotid-femoral pulse wave velocity using the Sphygmocor XCEL system (m/s)
Carotid to femoral pulse wave velocity (m/s) will be calculated using the Sphygmocor XCEL system. Changes from baseline will be compared at week 4 and week 8.
Time frame: Change in pulse wave velocity from baseline, week 4, and week 8
Change in ultrasound-assessed common carotid pulsatility index
An duplex PW-mode image of the common carotid artery will be recorded for 20 heart cycles using ultrasonography. Blood velocity will be evaluated directly on the ultrasound and pulsatility index will be calculated for each cardiac waveform as peak systolic velocity - end diastolic velocity / mean velocity and averaged over 20 cardiac cycles. Changes from baseline will be compared at week 4 and week 8.
Time frame: Change in carotid pulsatility index from baseline, week 4, and week 8
Change in ultrasound-assessed femoral artery blood flow response passive leg movement (PLM) (ml/min)
Femoral artery blood velocity and diameter will be continuously recorded using Doppler ultrasound for 1 minute at rest and during 1 minute of passive movement of the lower leg at the knee joint at a frequency of 1 hertz. Femoral artery blood flow will be calculated at baseline and during movement. The change in femoral artery blood flow will be calculated as peak blood flow during movement minus baseline blood flow. The change in femoral blood flow from baseline to peak is our assessment of femoral artery blood flow response to passive leg movement for which changes from baseline will be compared at week 4 and week 8.
Time frame: Change in femoral blood flow response to PLM from baseline, week 4, and week 8
Change in brachial artery flow-mediated dilation and reactive hyperemia
Brachial artery reactivity will be assessed via the flow-mediated dilation technique and percent dilation of the brachial artery in response to 5 minutes of forearm arterial occlusion will be assessed offline via Medical Imaging Applications Brachial Analyzer software. Brachial artery blood velocity will be measured on the ultrasound as mean velocity throughout the test and blood flow will be calculated using arterial diameter. Brachial artery blood flow area under the curve and peak brachial artery blood flow following cuff release will be assessed at baseline, week 4, and week 8.
Time frame: Change in FMD responses from baseline, week 4, and week 8
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University of Delaware