Clinical Research

This large scale study using data from of over 340,000 patients at 2,178 dialysis centers around the US, found that higher levels of solar UVB exposure were associated with lower systolic blood pressure, independent of temperature. This raises the possibility that insufficient sunlight could be a potential risk factor for hypertension.

When comparing circulating concentrations of vitamin D less than 17.8 ng/mL compared to greater than 29.2 ng/mL, the prevalence of peripheral artery disease (PAD) was reduced by 80%. Furthermore, for each 10 ng/mL lower 25(OH)D serum concentration the multivariable-adjusted prevalence ratio of PAD was 1.35.

A study of 1739 participants found that in those with hypertension, rate of cardiovascular disease was approximately twice as high in those with vitamin D levels less than 15 ng/mL as in those with vitamin D levels greater than 15 ng/mL. Exploratory analyses suggested a nonlinear relation between vitamin D levels and cardiovascular risk, with increased hazard for cardiovascular events at vitamin D levels below 15 to 20 ng/mL.

A study published in the American Journal of Cardiology found that vitamin D deficiency was associated with an up to twofold greater prevalence of several cardiovascular disease categories, with those with severe deficiency at greatest risk. The study found that vitamin D deficiency was associated with highly significant increases in the prevalence of diabetes, hypertension, hyperlipidemia, and peripheral vascular disease. Vitamin D levels were also highly associated with coronary artery disease, myocardial infarction, heart failure, and stroke, as well as with incident death, heart failure, coronary artery disease/myocardial infarction. Of special note was the relation to total mortality. Adjusted relative death rates increased 20% with low vitamin D (16-30 ng/mL) and 77% with very low vitamin D levels (less than 15 ng/mL).

An evaluation that considered the results of randomized control trials, prospective, cross-sectional, and epidemiological studies concluded that all relevant Hill criteria for a causal association in a biological system are satisfied to indicate a low vitamin D level as a cardiovascular disease risk factor.

This meta-analysis demonstrated a generally linear, inverse association between circulating vitamin D ranging from 8 to 24 ng/mL and risk of cardiovascular disease. When looking at participants without baseline cardiovascular disease, they saw a 7% reduction in cardiovascular disease per 10 ng/mL increase in vitamin D level.

In looking at data from 12,644 people in the National Health and Nutrition Survey III, mean systolic blood pressure was 3.0 mm Hg lower and diastolic blood pressure was 1.6 mm Hg lower for participants with vitamin D levels greater than 34.3 ng/mL compared to participants with vitamin D level less than 16.2 ng/mL, adjusting for age, sex, ethnicity, and physical activity.

This retrospective review of 153 older adults with hypertension and mild cognitive impairment found significant improvements in recognition memory and systolic blood pressure following vitamin D supplementation (≥5,000 IU/day for at least 6 months) compared with a control group that received no or minimal supplementation. In adjusted multivariable regression analyses, the supplemented group showed an additional 1.8 point improvement in recognition memory and a 10.7 mmHg reduction in systolic blood pressure.

This meta-analysis of 41 clinical trials in a total of 3,434 participants showed that vitamin D supplementation (mean of 2,795 IU) for 6 weeks to 3 years reduced serum total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels.