Abstract 9253: A Randomized Controlled Trial of the Effects of Vitamin D Supplementation on Central Blood Pressures and Aortic Stiffness in Native American Women
Background: Low vitamin D status has been linked to increased cardiovascular disease (CVD) risk. Low vitamin D levels, hypertension, and CVD are highly prevalent in Native American populations. However, it is unclear if vitamin D supplementation improves central blood pressure or arterial stiffness in Native American women.
Methods: Healthy postmenopausal Native American women without known CVD and with screening serum 25-hydroxyvitamin D (25(OH)D) between 10-60 ng/mL were randomized to receive daily vitamin D3 either 400 IU or 2,500 IU for 6 months. Central systolic blood pressure (cSBP), central pulse pressure (cPP) and aortic augmentation index (AIx) were estimated by tonometry (AtCor Medical, Sydney, Australia) at baseline and after 6 months of vitamin D supplementation. General linear models were used to evaluate cross-sectional and longitudinal associations. Repeated measures models were adjusted for baseline 25(OH)D.
Results: At baseline, study volunteers (n=98) were mean (standard deviation) 61 (7.3) years old. Screening 25(OH)D was 26.4 (11.0) ng/mL; 25(OH)D was less than 20 ng/mL in 33 (34%) participants and between 20-30 ng/mL in 29 (29.6%) participants. Screening 25(OH)D was similar between the two treatment groups (p=0.291), as were baseline cSBP, cPP, age, body-mass index, glucose, lipids, and high sensitivity C-reactive protein levels (all p>0.1). Screening 25(OH)D was associated with cSBP (p=0.022) and cPP (p=0.007), but not AIx (p=0.807). Treatment with 2,500 IU of daily vitamin D3 did not affect cSBP (p=0.546), cPP (p=0.614), or AIx (p=0.103) compared to 400 IU daily.
Conclusions: Despite relatively low serum 25(OH)D at baseline, 6 months of vitamin D supplementation did not improve central blood pressure parameters or arterial stiffness in Native American women.
- © 2013 by American Heart Association, Inc.