Few studies have investigated the incidence of eating disorders, so the authors set out to determine the incidence of diagnosed anorexia nervosa, bulimia nervosa and other non-specified eating disorders in primary care over a 10-year period in the UK (2000), to see how the incidence had changed and the most common age of diagnosis.
Eating disorders have the highest death rates of all mental disorders, and understanding changes in their incidence over time and by age and gender is essential to ensure timely diagnosis and appropriate service provision.
The researchers used data from the General Practice Database, which contains anonymised records of 5% of the UK population to identify all cases of eating disorder diagnosed between 2000 and 2009. They found a total of 9072 cases.
Analysis of the data revealed that in 2000 there were 32.3 new cases of eating disorder per 100,000 population aged between 10 and 49 years, and that this rose steadily to 37.2 new cases per 100,000 by 2009.
Despite other research suggesting a decrease in the incidence of bulimia, the incidence of bulimia and anorexia remained stable over the 10 years and it was new cases of eating disorder not otherwise specified which were responsible for the overall rise. The incidence of these unspecified eating disorders, which have been far less studied than bulimia and anorexia and are the most common type seen in hospital care (60% of cases seen in specialist services), has not been estimated previously in general practice care. However, publication of the new Diagnostic and Statistical Manual of Mental Disorders (DSM 5) last week is expected to mean that the majority of these cases will be diagnosed with anorexia, bulimia or a new condition of binge eating disorder in future.
The data showed that girls aged 15 to 19 years and boys aged 10 to 14 had the highest incidences of new diagnoses of eating disorder.
Two girls in every 1000 aged 15 to 19 years are likely to be diagnosed with an eating disorder every year, which means that there are around 4610 new cases in girls of this age group each year. As a result, eating disorder is probably the most common new onset mental health disorder in adolescent girls after depression, the authors say. In 2009, the incidence of new diagnoses of depression was 11.9 per 1000 in girls of this age group.
In girls aged 10-19 years, there are nine times as many new cases of eating disorder (1.2 per 1000 population) diagnosed every year as there are cases of type 1 diabetes (0.26 new cases per 1000), and about half as many new diagnoses as there are of type 2 diabetes (3.6 new cases per 1000).