The Incidence of Eating Disorders in Great Britain

From 1988-1993, the incidence of anorexia nervosa (AN) reported by primary care physicians in Great Britain remained stable, but the incidence of bulimia nervosa (BN) increased by 300%. Laura Currin and colleagues recently assessed whether the incidence of AN has remained stable and if the incidence of BN continues to rise since that time (Br J Psychiatry 2005;186:132).

The authors analyzed the annual incidence rates of eating disorders by using the General Practice Research Database, or GRPD (www.grpd.com). In the British health care system, most patients will pass through primary care even if they are referred to a specialist later. The GRPD was searched for newly recorded cases of AN and BN in the five years between 1994 and 2000. Then, annual incidence rates for women 10 to 39 years of age were calculated.

AN incidence remained stable; BN rose

Between 1994 and 2000, the incidence of AN remained stable for women from 10-39 years of age; in 1988, the rate was 18.5 per 100,000 population and in 2000, the rate was 20.1 per 100,000. In 2000, the age- and gender-adjusted incidence of AN diagnosed in primary care practices was 4.7 per 100,000 population. The relative risk ratio for females to males was 12:1.

The results for BN were quite different. Just as was shown by Turnbull and associates (1996), there was a marked increase in the incidence of BN cases diagnosed by primary care physicians. Although the number of cases increased from 1988 to 2000, the incidence rate then fell by 38.9%. In 2000 the age- and gender-adjusted incidence of BN in primary care settings was 6.6 per 100,000. The incidence rate for females was 12.4 per 100,000, compared with 0.7 males per 100,000. The female: male risk ratio was about 18:1, according to the authors.

Why the change in BN incidence?

The authors suggest several possible explanations for the surge and decline of cases of BN in the 1990s. One reason may be that patients can now seek help from sources other than their primary care physicians, including Internet-based messaging and e-mail services. The authors note that the lessening incidence in identified cases of BN also mirrors a decline in articles on eating disorder research in the UK. And, another, more colorful, reason they give for the decline was the intense media attention given to the late Princess Diana’s battle with bulimia nervosa. The authors surmise that this might have contributed to the apparent rise in incidence because public and media interest may have focused greater-than-normal attention on bulimic symptoms. Thus, a portion of the 1990s peak might have been caused by identification of long-standing cases rather than a true increase in community incidence.

The authors note that further research is needed to see whether the reported incidence of BN will continue to decline or if it will stabilize like AN. They add that last year the National Institute for Clinical Excellence called for attention to the lack of research about adolescents with BN. Since this age group now shows the highest incidence of bulimia in primary care settings in Great Britain, they believe renewed emphasis on research is needed in this age group.