Vitamin D deficiency in patients with erythropoietic protoporphyria

• DOI: 10.1007/s10545-008-1037-0
• Publication Date: 2009-01-22T11:44:31Z
• Authors: J. M. C. Spelt; F. W. M. de Rooij; J. H. P. Wilson; A. A. M. Zandbergen
• Keywords: Erythropoietic protoporphyria; Human genetics

SummaryBackground:The main symptom of patients with erythropoietic protoporphyria (EPP) is painful photosensitivity, starting within minutes of sun exposure and leading to sun‐avoidance. As 80–100% of vitamin D is synthesized under the influence of sunlight, we investigated whether the avoidance of sunlight exposure in the Dutch EPP patient population causes vitamin D deficiency. Furthermore, we studied the relation between vitamin D levels, total erythrocyte protoporphyrin and quality of life.Methods:In a cross‐sectional study of 48 Dutch EPP patients (mean age 41.4 years; range 16–77; 23 male, 25 female), we assessed serum 25‐hydroxyvitamin D (25(OH)D) levels between June and November 2007, as well as total erythrocyte protoporphyrin (TEP) levels and Dermatology Life Quality Index (DLQI) scores.Results:Mean serum 25(OH)D was 66 nmol/L (range 18–140, quartiles 36, 87). Twenty‐two patients (46%; 15 male, 7 female) were vitamin D deficient. There was a significant difference (p = 0.029) in mean serum 25(OH)D between female (mean 75 nmol/L, range 18–140) and male patients (mean 55 nmol/L, range 18–115). The level of serum 25(OH)D showed a negative correlation with total erythrocyte protoporphyrin (TEP) (Pearson rank correlation (rp) = −0.337; p = 0.034). Serum 25(OH)D was inversely associated with scores of the Dermatology Life Quality Index (DLQI) (Spearman's rho correlation (rs) = −0.486; p = 0.001).Conclusions:The prevalence of vitamin D deficiency is high in the Dutch EPP population, especially in male patients, and correlates with the severity of EPP. Screening for and treatment of vitamin D deficiency should therefore be implemented in the care of these patients.