The overall incidence of eating disorders increased between 2000 and 2009, says new register-based UK study

Eating disorders are chronic conditions associated with high mortality and morbidity as highlighted by a previous Mental Elf blog in 2011.

Eating disorders are categorised into three main groups: i. Anorexia Nervosa (AN), ii. Bulimia Nervosa (BN) and iii. Eating Disorder Not Otherwise Specified (EDNOS).

Using ICD 10 criteria, EDNOS includes atypical AN and atypical BN as well as “eating disorder unspecified” and there seems to be less published research into this group than AN and BN.

A register-based study published earlier this year in BMJ Open had 3 clear objectives:

To determine the incidence of eating disorders in UK primary care between 2000 and 2009 by age group and gender
To investigate changes in incidence between 2000 and 2009
To identify age peaks at incidence by gender

Methods

The data was collected from the General Practice Research Database, a database compiled from around 400 representative UK practices. From this database, the team looked at new diagnoses within a 10 year period (between 1 January 2000 and 31 December 2009) of AN, BN or EDNOS in male and female patients aged between 10-49 years. Patients who had a diagnoses of both AN and BN were assigned to the correct group using a diagnostic algorithm that measured BMI and symptoms at presentation.

Results

The bottom line of the study was that in both male and female patients, the overall incidence of eating disorders increased between 2000 and 2009.

Age-standardised rates of ED were 32.3 (95% CI 31.7 to 32.9) per 100 000 in 2000 and 37.2 (95% CI 36.6 to 37.9) per 100 000 in 2009, showing a statistically signiﬁcant increase (p<0.000001).

According to this study, EDNOS (Eating Disorders Not Otherwise Specified) have become the most common type of eating disorder in UK men and women

Interestingly, for both males and females, a statistically significant increase was seen in EDNOS, whereas incidence of AN and BN stayed roughly the same throughout the period. EDNOS was the most commonly diagnosed ED in males throughout the study period. In females, at the start of the study period BN was more common but now this has been overtaken by EDNOS.

In terms of age group incidence peaks:

In females, the peak incidence was seen in the 15-19 year olds: 164.5 per 100,000 (95% CI 144.6 to 186.4)

In males, the peak incidence was in the 10-14 year olds: 17.5 per 100,000 (95% CI 11.1 to 26.2)

Conclusions

One of the strengths of this study lies in the fact that it is primary care based, thereby avoiding a referral bias. However this still relies on the fact that the case has been “detected” and the authors do comment on the likelihood of large numbers of cases in the community without diagnoses. So, the figures given in the research are likely to be an underestimate of the true incidence in the UK population.

The researchers suggest that the actual incidence rates are likely to be higher than the results of this study

As discussed by the authors, it is impossible to say from this study whether the results show a true increase in the number of people suffering from EDNOS or whether this is due to better detection rates as clinicians have a greater awareness of atypical eating disorders.

They conclude:

Future research should clarify whether the increase seen in this study reflects a true community increase or better detection. Our findings have important implications for public health, healthcare provision and understanding the development of EDs.