Published in:
01-12-2010 | Short Report
Vitamin D deficiency in patients with erythropoietic protoporphyria
Published in: Journal of Inherited Metabolic Disease | Special Issue 3/2010
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Background:
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 (r
p) = −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 (r
s) = −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.