Prevalence of porphyria cutanea tarda in Madrid, Spain, and association between porphyrinuria and alcohol intake in a linear multiple regression model Prevalencia de porfiria cutánea tarda en Madrid y asociación entre la porfirinuria y el consumo de etano

Abstract

BACKGROUND: The application of a simple fluorometric analytical method enabled us to quantify the urinary porphyrin excretion and to establish the prevalence of porphyria cutanea tarda (PCT) in the town of Madrid, Spain, in a cross-sectional study. PATIENTS AND METHODS: The study assessed 1,613 subjects from three districts in Madrid, in whom further variables potentially related to porphyrinuria such as ethanol intake or -in women- oral contraceptive use were measured and recorded. RESULTS: The estimated prevalence of the disease was 1.24 cases per 1,000 inhabitants (95% confidence interval 0.15-4.47 per thousand). After excluding from the study sample all cases with existent disease, an analysis was performed to ascertain an unilateral tolerance interval for urinary porphyrin concentration in the adult population; this level was established at 181.2 μg/l. The effect of ethanol intake on porphyrinuria was considered significant using a multiple linear regression model adjusted for the