Background Decrease in vitamin D levels in patients with systemic lupus erythematosus (SLE) arouses particular interest. Vitamin D levels and their correlation with bone mineral density (BMD) loss are still seen as contradictory.

Objectives To study serum vitamin D levels in SLE women and to estimate their correlation with BMD and disease activity.

Methods 101 SLE women and 30 individuals in a control group participated in the study. The activity of SLE was evaluated by SLEDAI. The average age of patients was 47.12 ± 0.14 years, in the control group it was 46.17 ± 0.12. Serum levels of C-reactive protein (CRP) and 25-hydroxyvitamin D (25(ОН)D) were measured in all participants. Changes in BMD of the lumbar spine and hip were determined by dual-energy X-ray densitometry.

Results In patients with SLE, the average level of 25(ОН)D equalled 14.6 ± 1.19 ng/ml, and in the individuals from the control group, it was 1.9 times higher, constituting 24.7 ± 1.32 ng/ml.

In SLE women with normal BMD (T score > -1.0 SD) vitamin D deficiency (< 20 ng/ml) was detected in 18.3%. In the group with osteopenia (T-score from -1.0 to -2.5 SD), the proportion of individuals with vitamin D deficiency has increased to 26.7%. In women with osteoporosis (T-score ≤ -2.5 SD), vitamin D deficiency was found in 63.9%. In the group of patients with the maximum CRP level there were only 10% of persons with the optimal (> 30 ng/ml) 25(ОН)D level, 40% had insufficiency (20-30 ng/ml), while deficiency (< 20 ng/ml) was detected in every second patient. Among patients with optimal CRP levels, only every fourth person was diagnosed with vitamin D deficiency, 10% of the individuals had vitamin D insufficiency, while 65% had optimal vitamin D levels. Decrease in vitamin D level was closely associated with SLE activity revealed by SLEDAI (r = -0.44; р < 0.05).

Conclusion The average vitamin D level in SLE women is likely to be lower than that in the control group. Decrease in vitamin D levels was associated with BMD loss and high inflammatory process as well as the disease activity according to CRP and SLEDAI.

REFERENCES: NIL.

Acknowledgements: NIL.

Disclosure of Interests None Declared.