Vitamin D levels in 87 Asian patients with cutaneous lupus erythematosus: a case–control study
Summary
Background
Cutaneous lupus erythematosus (CLE) is an autoimmune disease, often exacerbated by sun exposure. Patients are encouraged to avoid sun exposure, therefore predisposing them to vitamin D deficiency.
Aim
To investigate the prevalence of and risk factors for vitamin D deficiency in patients with CLE.
Methods
Total serum 25-hydroxy vitamin D (25(OH)D) was measured in 87 consecutive patients with CLE and in 79 controls. Clinical characteristics, disease severity, medications used and lifestyle factors were analysed and compared to determine risk factors for inadequate (25(OH)D), defined as a serum (25(OH)D) level of < 20 μg/L.
Results
We found that 51% (n = 44) of the patients with CLE had 25(OH)D levels of < 20 μg/L compared with 73% (n = 58) of the controls (P < 0.01). No significant differences in (25(OH)D) levels were found between cases and controls with regard to age, sex, ethnicity, smoking, sun exposure, sunblock use or vitamin D supplementation. Treatment with antimalarials showed a statistically significant association with lower vitamin D levels.
Conclusion
Low levels of vitamin D were found in both patients with CLE and controls. Despite being on vitamin D supplementation and living in an equatorial location, our Asian patients with CLE still had low levels of vitamin D. It is therefore important to ensure adequate vitamin D supplementation in patients with CLE, especially for those who are on antimalarial therapy.
