Vitamin D levels in children, adolescents, and young adults with juvenile-onset systemic lupus erythematosus: a cross-sectional study

Background: Hypovitaminosis D is common in the general population. Although many studies on 25-hydroxyvitamin D (25(OH)D) are available on systemic lupus erythematosus (SLE), few data are reported in juvenile-onset SLE (JSLE) patients. Design: This study aimed to assess serum 25(OH)D levels in JSLE patients and to identify risk factors for vitamin D deficiency in this population. Methods: Forty-five Caucasian JSLE patients (36 females, nine males; mean age 18.9 +/- 6.3 years) and 109 age- and sex-matched healthy controls entered the study. Dual-energy X-ray absorptiometry (DXA) scans of the lumbar spine, serum calcium and phosphate, bone-specific alkaline phosphatase (BSAP), parathyroid hormone (PTH), and 25(OH)D were assessed. The data were compared with an age-and sex-matched control group including 109 Caucasian healthy subjects. Results: JSLE patients exhibited lower 25(OH)D levels than controls (p<0.005), with the lower values observed in patients with active vs. inactive disease (p<0.05). JSLE patients exhibited reduced total calcium levels (p<0.001) and higher phosphate levels (p<0.001), BSAP (p<0.001) and PTH (p<0.001) than controls. In addition, JSLE patients exhibited lower spine bone mineral apparent density (BMAD) SDS values than controls (p<0.001), with higher values in patients with 25(OH)D sufficiency and insufficiency than in those with 25(OH)D deficiency (p<0.001). Conclusions: Patients with JSLE have significantly lower 25(OH)D levels than controls. Therefore, vitamin D supplementation may be useful to normalize bone mass and quality in subjects with JSLE.