Prevalence of eating disorders in Norwegian general hospitals 1990-1994: admissions per year and seasonality

To study the occurrence of eating disorders in patients admitted to somatic hospitals.

For all, approximately 3.3 million, admissions to Norwegian general hospitals in the period 1990-1994, admissions with the primary diagnoses for the eating disorders anorexia nervosa (AN) and bulimia nervosa (BN) were selected. Data on gender, age groups, emergency admission, different hospital types, length of stay, seasonal differences, and differences along the latitudes were related to the primary diagnosis.

A small number of men with eating disorders were admitted; 9-17 times more women were admitted (140-183 female and 11-15 male admissions per year). The male/female ratio was on the mean 8% for the period. About two thirds to three fourths were emergency admissions. The mean length of stay was 12-19 days, and the median stay was 6-8 days. A significant (p = .03) season of admission was found. A significant number of admissions occurred in the beginning of March and a minimum in June. The best model was two harmonics without trend.

There are few reports on eating disorders in somatic inpatients in the literature, but our results indicate that it is important to consider the general hospital in this connection. Bulimia nervosa was rather unusual in the present study, while anorexia nervosa was prevalent, specifically for women. Seasonality has rarely been reported in relation to hospitalization.