Vitamin D may reduce hypertension risk

Vitamin D insufficiency in early adulthood may be a risk factor in subsequent hypertension among women, a new US study suggests.

In an observational study, blood pressure and vitamin D levels were measured in 599 women aged 24–44 years at the beginning of the trial and again 14 years later (1). The results showed that vitamin D insufficiency – serum 25(OH)D below 80 nmol/liter – was not significantly associated with concurrent systolic hypertension (?140 mm Hg) at baseline. However, vitamin D insufficiency was associated with a fivefold increased risk of systolic hypertension 14 years later after adjusting for age, body fat percentage, antihypertensive medication use, and smoking. In the observed group a total of 81% of women had inadequate blood concentrations of vitamin D. The researchers commented that these prospective results indicate a role of vitamin D insufficiency in early adulthood as a risk factor in subsequent hypertension among women.

The study results confirm previous results indicating a link between long-term vitamin D insufficiency and elevated blood pressure (2-4). Although there is evidence highlighting the relationship between vitamin D and all cause mortality (5), cardiovascular events (6, 7) and blood pressure, questions remain about the causality of these associations, the timing of the vitamin D impact on cardiovascular health, and the magnitude of effect generated by vitamin D. Clinical trials have attempted to address these questions but with mixed results: One trial with dietary supplementation, for example, indicated systolic blood pressure was reduced by 7.4 mm Hg (8), while another clinical trial identified no significant difference in blood pressure between the treated and control groups (9), which may be due to the low vitamin D treatment dosage (400 IU).

The researchers noted that long-term studies measuring vitamin D and blood pressure at frequent intervals would be warranted. Further, the potential link between vitamin D, body fat percentage, and hypertension would merit further investigation.

1. Griffin F. C. et al. Vitamin D and subsequent systolic hypertension among women. American Journal of Hypertension. 2011; 24(3): 316–321.
2. Scragg R. et al. Serum 25-hydroxyvitamin D, ethnicity, and blood pressure in the Third National Health and Nutrition Examination Survey. Am J Hypertens. 2007; 20:713–719.
3. Wang L. et al. Dietary intake of dairy products, calcium, and vitamin D and the risk of hypertension in middle-aged and older women. Hypertension. 2008; 51:1073–1079.
4. Almirall J. et al. Association of low serum 25-hydroxyvitamin D levels and high arterial blood pressure in the elderly. Nephrol Dial Transplant. 2010; 25:503–509.
5.  Melamed M. L. et al. 25-Hydroxyvitamin D levels and the risk of mortality in the general population. Arch Intern Med. 2008; 168:1629–1637.
6. Pilz S. et al. Association of vitamin D deficiency with heart failure and sudden cardiac death in a large cross-sectional study of patients referred for coronary angiography. J Clin Endocrinol Metab. 2008; 93:3927–3935.
7. Giovannucci E. et al. 25-hydroxyvitamin D and risk of myocardial infarction in men: a prospective study. Arch Intern Med 2008; 168:1174–1180.
8.  Pfeifer M. et al. Effects of a short-term vitamin D and calcium supplementation on blood pressure and parathyroid hormone levels in elderly women. J Clin Endocrinol Metab. 2001; 86:1633–1637.
9. Margolis K. L. et al. Women’s Health Initiative Investigators. Effect of calcium and vitamin D supplementation on blood pressure: the Women’s Health Initiative Randomized Trial. Hypertension. 2008; 52:847–855.