SAN FRANCISCO — A study of 156 patients with systemic sclerosis in two European cities found that vitamin D deficiency was common, present in 28%.
Deficient levels of serum 25-hydroxyvitamin D (25[OH]D)—less than 10 ng/mL—were seen in 29 (32%) of 90 patients in Paris and 15 (23%) of 66 in southern Italy, Dr. Alessandra Vacca and her associates reported in a poster presentation at the annual meeting of the American College of Rheumatology. In addition, 84% of all patients had insufficient vitamin D levels (less than 30 ng/mL), seen in 75 (82%) of the Parisians and 57 (86%) of the Italians.
Overall, patients had a mean age of 57 years, and 97% were female. The mean vitamin D value in the two cohorts was 19 ng/mL, said Dr. Vacca of the University of Cagliari.
The rates of vitamin D deficiency did not differ significantly between cities and so were independent of the different UV radiation levels in the northern and southern cities. Rates of vitamin D deficiency also were independent of usual levels of vitamin D supplementation (800 IU/day), taken by 30% of Parisian patients and 45% of Italian patients.
Because conventional doses of vitamin D supplementation did not prevent vitamin D deficiency, higher-dose supplementation may be needed in patients with systemic sclerosis, especially those with inflammatory activity, she said.
Low vitamin D levels were associated with pulmonary fibrosis (P = .04), systolic pulmonary arterial hypertension (P = .004), and inflammatory activity indicated by acute phase reactants—erythrocyte sedimentation rate (P = .004) and C-reactive protein values (P = .01). There was a significant negative correlation between low vitamin D levels and European disease activity scores (P = −0.04). A mild negative association was seen between vitamin D deficiency and anticentromere antibodies.
Low vitamin D levels may be linked to multiple risk factors, Dr. Vacca suggested, including scarce sun exposure due to disability, insufficient intake and malabsorption of vitamin D due to gastroenteric involvement, or use of drugs that can alter metabolism of vitamin D. There was no association between vitamin D deficiency and other markers of impaired malabsorption such as hemoglobin, ferritin, or albuminemia. No associations were found between vitamin D deficiency and acro-osteolysis, calcinosis, or Medsger's disease severity score.
The investigators reported no conflicts of interest related to this study.