A significant nationwide increase in the prevalence of eating disorders in Japan: 1998-year survey

Abstract

Objective: To investigate the prevalence and the clinico-epidemiological features of eating disorders (ED) in Japan. Methods: In January 1998, a self-reported questionnaire, asking about the number of ED was mailed to 23,401 institutions and a second questionnaire asking about the clinoco-epidemiological features of ED was mailed to 1404 institutions, the institutions being located throughout Japan. We calculated the 1-year prevalence rates of ED from these data. Results: The prevalence rates of anorexia nervosa in this survey showed 10.0 cases per 100,000 of general population, which were four times higher than those in 1993. The rates for bulimia nervosa indicated 5.2 cases per 100,000, which were 4.7 times higher than in 1993. With respect to clinico-epidemiological features, short-term cases (duration of illness <2 years) were detected among approximately one-third of the patients in their 20s, and half of the patients more than 30 had long-term cases (>9 years). Moreover, fewer than half of ED patients indicated “improved” in clinical course, “sufficient” in family support and “adjusted” in social adaptation. Conclusions: These findings suggest the expansion of age groups with ED, vulnerable family structure, and insufficient social support systems in contemporary Japan, and also suggested that the prevalence rates in Japan would soon reach those in the west.