Background/Purpose:

Vitamin D is a steroid hormone that not only functions in maintaining calcium and bone metabolism, but also displays immunoregulatory and anti-inflammatory properties. Recent studies demonstrate a correlation between vitamin D insufficiency / deficiency and increased disease activity in SLE, but less is known about the role of vitamin D in specific complications of SLE. In the current case-control study, we aimed to evaluate the relationship between low levels of vitamin D and disease activity in SLE compared to controls.

Methods:

We compared serum 25-hydroxyvitamin D (25(OH)D) levels between diagnosed SLE cases with controls, and examined disease characteristics in relationship to 25(OH)D status among cases. The majority of SLE patients and all controls are Gullah African Americans recruited prospectively into the SLE in Gullah Health (SLEIGH) study, currently ongoing since 2003. SLE disease characteristics were assessed by the SLEDAI scores to measure disease activity and damage, respectively. Patients met at least 4 of the 11 ACR Classification Criteria for SLE and active disease was defined as SLEDAI ≥ 6. Data was utilized from a RedCap database of baseline and follow-up visits and included the following: demographics, medical history, SLEDAI, and 25(OH)D serum levels. Our longitudinal population cohort consisted of 392 diagnosed SLE patients (90.7% women, 74% African American; mean age (visit age) 40.9 +/- 15.4 years, mean age at diagnosis 30.9 +/- 14.5 years) and 127 healthy controls (91.7% women; 100% African American, mean age 43.1 +/- 12.8 years) were used. 

Results: Out of the 352 patients, 65.2 patients had vitamin D insufficiency [25(OH)D < 30 ng/ml], 40.3 patients had vitamin D deficiency [25(OH)D < 20 ng/ml], and 10.8 patients had severe vitamin D deficiency [25(OH)D < 10 ng/ml]. In the control group, 92.1 subjects had vitamin D insufficiency, 74.8 subjects had vitamin D deficiency, and 40.9 subjects had severe vitamin D deficiency. 25(OH)D deficiency was significantly associated with African Americans (OR 3.74, 95% CI 1.06-2.83), obese SLE patients (OR 1.56, 95% CI 0.95-2.58), current smokers (OR 9.50, 95% CI 1.96-46.15), age at visit (OR 0.97, 95% CI 0.95-0.99), active disease SLE patients (OR 2.2, 95% CI 18.4-22.2), and SLEDAI score (p=0.03, OR 1.09). 

Conclusion:

Vitamin D deficiency was prevalent in SLE patients (65.2%) and controls (92.1%). African Americans were significantly more likely to be 25(OH)D deficient (86.2%, p<0.01), adjusting for visit age, BMI, gender, smoking status, and disease duration. 25(OH)D concentration is significantly associated with obese SLE patients, current smokers, visit age, and having high disease activity by SLEDAI. Our study suggests that vitamin D deficiency, especially in African American patients, is significantly associated with disease activity in SLE.

« Back to 2015 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/investigating-the-role-of-vitamin-d-in-patients-with-sle/