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Circulation. 2015 Jan 20;131(3):254-62. doi: 10.1161/CIRCULATIONAHA.114.011732. Epub 2014 Oct 30.

Vitamin D therapy in individuals with prehypertension or hypertension: the DAYLIGHT trial.

Author information

1
From the Cardiology Division, Department of Medicine, University of Alabama at Birmingham, Birmingham (P.A.); Department of Biostatistics (Y.S., F.H.) and Division of Cardiovascular Medicine, Department of Medicine (D.C.O., T.J.W.), Vanderbilt University, Nashville, TN; Integrative Health Research Center, Abbott Northwestern Hospital, Minneapolis, MN (J.D., G.P.); Division of Cardiology, Department of Medicine, Brigham & Women's Hospital, Harvard Medical School, Boston, MA (M.S.S., S.C.); Esoterix Clinical Lab Services, LabCorp, Research Triangle Park, NC (A.V.); Division of Cardiology, Department of Medicine, Hartford Hospital, Hartford, CT (H.S., B.T.); Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston (E.C., D.G., J.R.Y., C.K., M.T., C.N.-C.); Division of Cardiology, Cultural Wellness Center, Minneapolis, MN (A.A., S.M.S.); and Division of Nephrology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL (M.W.).
2
From the Cardiology Division, Department of Medicine, University of Alabama at Birmingham, Birmingham (P.A.); Department of Biostatistics (Y.S., F.H.) and Division of Cardiovascular Medicine, Department of Medicine (D.C.O., T.J.W.), Vanderbilt University, Nashville, TN; Integrative Health Research Center, Abbott Northwestern Hospital, Minneapolis, MN (J.D., G.P.); Division of Cardiology, Department of Medicine, Brigham & Women's Hospital, Harvard Medical School, Boston, MA (M.S.S., S.C.); Esoterix Clinical Lab Services, LabCorp, Research Triangle Park, NC (A.V.); Division of Cardiology, Department of Medicine, Hartford Hospital, Hartford, CT (H.S., B.T.); Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston (E.C., D.G., J.R.Y., C.K., M.T., C.N.-C.); Division of Cardiology, Cultural Wellness Center, Minneapolis, MN (A.A., S.M.S.); and Division of Nephrology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL (M.W.). thomas.j.wang@vanderbilt.edu.

Abstract

BACKGROUND:

A large body of epidemiological and experimental evidence suggests that vitamin D deficiency may promote hypertension. This raises the possibility that vitamin D supplementation could be a simple intervention to reduce blood pressure, but data from prospective, randomized trials are limited.

METHODS AND RESULTS:

A double-blind, randomized, controlled trial was conducted at 4 sites in the United States. We enrolled 534 individuals 18 to 50 years of age with low vitamin D status (25-hydroxyvitamin D levels ≤25 ng/mL) and systolic blood pressure of 120 to 159 mm Hg. Participants were randomized to high-dose (4000 IU/d) versus low-dose (400 IU/d) oral vitamin D3 for 6 months. The primary end point was change in mean 24-hour systolic blood pressure. Secondary end points included change in ambulatory diastolic blood pressure and clinic systolic and diastolic blood pressures. The median age was 38 years, and 62% of participants were men. Forty-six percent of participants were white, and 48% were black. The median 25-hydroxyvitamin D level at baseline was 15.3 ng/mL. Four-hundred fifty-five participants (85%) had at least 1 follow-up blood pressure measurement; 383 participants (72%) completed the full 6-month study. At the end of the study, there was no significant difference in the primary end point (change in mean 24-hour systolic blood pressure, -0.8 versus -1.6 mm Hg in the high-dose and low-dose arms; P=0.71) or in any of the secondary end points. Furthermore, there was no evidence of association between change in 25-hydroxyvitamin D and change in 24-hour systolic blood pressure at 6 months (Spearman correlation coefficient, -0.05, P=0.34). Results were consistent across prespecified subgroups.

CONCLUSIONS:

Vitamin D supplementation did not reduce blood pressure in individuals with prehypertension or stage I hypertension and vitamin D deficiency. Our findings suggest that the association between vitamin D status and elevated blood pressure noted in observational studies is not causal.

CLINICAL TRIAL REGISTRATION URL:

http://www.clinicaltrials.gov. Unique identifier: NCT01240512.

KEYWORDS:

blood pressure; dietary supplements; hypertension; vitamin D deficiency

[Indexed for MEDLINE]

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