Ethnic variations in the epidemiology of bullous pemphigoid in Israel

Background No ethnic or geographic predisposition to bullous pemphigoid (BP) was reported so far. Objective To evaluate trends in the incidence of BP in northern Israel, shedding light on differences between two distinct ethnic populations who inhabit the same region, namely Jews and Arabs. Methods Bullous pemphigoid incidence was retrospectively estimated from January 2000– December 2015 in two Israeli regions with a total population of 1.56 million inhabitants. Results A total of 287 new-onset BP patients (mean age: 77.6 ± 12.1) were identified. The incidence rate was 11.4 per million inhabitants per year (95% CI, 10.2–12.9). The crude incidence rate in Jews was 4.8-fold higher than that in Arabs (16.4 vs. 3.4 cases per million per year, respectively [P < 0.0001]). After adjusting for age, the discrepancy between the two populations diminished (11.7 vs. 8.9 cases per million per year, respectively) but remained statistically significant (P = 0.032). The incidence increased consistently from 7.6 cases per million per year in the calendar period 2000–2005 to 12.6 and 14.3 cases in 2006–2010 and 2011–2015, respectively (P < 0.0001). Bullous pemphigoid patients of Arab ancestry presented with the disease significantly earlier than Jews (69.5 ± 15.3 vs. 78.7 ± 11.1 years, respectively, P = 0.002). Conclusions The incidence of BP in northern Israel has increased in the last 16 years and is significantly higher among Jews compared to Arabs. The age of presentation is remarkably different between patients belonging to the two populations.