Assessing the prevalence of eating disorders in an Australian twin population

Objective: This paper examines the prevalence of disordered eating in a female Australian twin population aged between 28 and 90 years in 1993. Method: In two waves of data collection, the eating behaviour of 3869 female twins was first assessed in 1988-1989 by self-report questionnaire and then in 1992-1993 with a telephone interview, using the Semi-Structured Assessment for the Genetics of Alcoholism interview. Results: It was found that about 0.4% of the women have a lifetime prevalence of anorexia nervosa and 1.8% of the group have suffered from bulimia nervosa. The incidence of bulimia nervosa but not anorexia nervosa was markedly higher for those women under 45 (2.3% bulimia nervosa) than for those women 45 years or older. Furthermore, one in three women have at some stage in their life used some extreme method of weight control. Conclusions: The levels of bulimia nervosa and anorexia nervosa found are commensurate with those found in smaller studies in Australia and other parts of the world. The finding of widespread use of extreme weight control methods is of concern as this behaviour is a well-recognised precursor to more serious eating disorders.