Estimated Prevalence of Sjögren’s Syndrome in Japan: Findings from a Nationwide Epidemiological Survey

To estimate the prevalence of Sjögren’s syndrome (SS) in Japan, and to describe the clinico-epidemiological features, a nationwide epidemiological survey was conducted in 1994. The study consisted of two questionnaires distributed to the relevant departments of hospitals throughout Japan. The first questionnaire inquired the number of the patients treated in 1993, and the second one detailed clinico-epidemiological information of the patients reported. Following major epidemiological findings emerged from the study: (a) The total number of patients treated for SS in 1993, in Japan, was estimated as 17, 000 (95% confidence interval 15, 000-20, 000). The estimated crude prevalence rates were 1.9 and 25.6 per 100, 000 population in males and females, respectively, (b) The ratio of female to male patients was 13.7. The peak of age distribution of SS patients reported was in their fifties. The highest prevalence rate was observed among females with their sixth decade; being 62.2 per 100, 000 population.