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J Hypertens. 2011 Sep;29(9):1749-56. doi: 10.1097/HJH.0b013e328349666d.

No effect of ultraviolet radiation on blood pressure and other cardiovascular risk factors.

Author information

1
Epidemiology and Biostatistics, School of Population Health, University of Auckland, Auckland, New Zealand. r.scragg@auckland.ac.nz

Abstract

OBJECTIVES:

Recent epidemiological studies have reported inverse associations between vitamin D status and blood pressure. The study aim is to determine if exposure to ultraviolet B radiation, which synthesizes vitamin D, lowers blood pressure, compared with ultraviolet A radiation.

METHODS:

Men and women (n = 119) with low vitamin D levels [serum 25-hydroxyvitamin D [25(OH)D] <50 nmol/l], completed a randomized clinical trial carried out during winter. Blood pressure was measured for 12-14 h with an ambulatory monitor at baseline and 12 weeks. In between, participants received 24 whole body exposures of either ultraviolet B (n = 58) or ultraviolet A (n = 61) over 12 weeks.

RESULTS:

Mean (SD) 25(OH)D increased from 43.7 (9.7) to 92.6 (16.9) nmol/l in the ultraviolet B arm after 12 weeks, and from 45.4 (9.2) to 64.9 (11.3) nmol/l in the ultraviolet A arm. However, mean blood pressure, which was similar for the ultraviolet B and ultraviolet A at baseline (134.9/79.2 vs. 132.9/77.8 mmHg; P = 0.59 and 0.56, respectively), did not change from baseline to 12 weeks in either group. The mean change [95% confidence interval (CI)] in blood pressure over this period in the ultraviolet B group compared with the ultraviolet A group was -2.2 (-7.8, 3.3) mmHg for systolic (P = 0.42) and -2.7 (-6.5, 1.0) mmHg for diastolic (P = 0.15).

CONCLUSION:

Exposure to ultraviolet B did not lower blood pressure. Our results suggest that if vitamin D protects against cardiovascular disease, it involves some mechanism other than blood pressure.

PMID:
21720260
DOI:
10.1097/HJH.0b013e328349666d
[Indexed for MEDLINE]

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