Background/Purpose: Vitamin D insufficiency/deficiency is common in SLE. Both a cohort study and a randomized clinical trial have proven that Vitamin D supplementation improves SLE global activity and the urine protein/cr ratio. We assessed whether there was an association between serum Vitamin D and blood pressure.

Methods: This analysis is based on clinic visits of a large SLE cohort after May 2009 when serum 25-hydroxyvitamin D was measured regularly. 1305 different patients were observed from 1 to 32 visits (the median was 10). The patients were 92% female, 50% Caucasian, 41% African American. Age ranged from 17 to 89. When the 25-OH Vitamin D level was below 40 mg/ml, the patient was prescribed supplemental vitamin D, usually 50,000 IU weekly.

Results: The “between-person” analysis addressed the question of whether those who tend to have low vitamin D also tend to have high systolic blood pressure. Among patients whose mean vitamin D was under 40, those whose mean vitamin D was 10 points higher had a mean SBP that was 3.8 mmHG lower (p<0.0001). For example, comparing those with a mean of vitamin D of 25 to those with a mean vitamin D of 35, we found a 3.8 mmHG lower mean SBP in the latter group (Table 1). There was no evidence of an association between vitamin D levels and SBP among those with mean vitamin D greater than 40 (p=0.27 or p=0.31 for unadjusted or adjusted analysis respectively). Table 1: Difference in person-specific mean SBP per 10 ng/ml difference in person-specific mean vitamin D

¹ Adjusted for age, age-squared, sex, race, proportion of time on Plaquenil, mean prednisone dose, mean BMI. The “within-person” analysis addressed the question of whether a person tends to have higher SBP when his/her vitamin D is lower than his average vitamin D (Table 2). Table 2: Difference in SBP at each visit per 10 ng/ml difference in the person’s vitamin D at that visit and the person’s average vitamin D.

¹ Adjusted for age, age-squared, sex, race, proportion of time on Plaquenil, mean prednisone dose, mean BMI. If a person’s vitamin D was higher than her mean vitamin D by 10 ng/ml and she had vitamin D below 40 ng/ml, then the expected blood pressure will decrease by 1.3 mmHG (p<0.0001).

Conclusion: Both the “between person” and “within person” analyses provide evidence that among those with vitamin D below 40 ng/ml, a higher vitamin D level was associated with lower systolic BP. As with disease activity, achieving a level above 40 ng/ml did not lead to further improvement. Vitamin D supplementation has now been seen to help not just disease activity but also the most important traditional cardiovascular risk factor, hypertension.

« Back to 2016 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/vitamin-d-improves-systolic-blood-pressure-in-sle/