Eating disorders of the bulimic type : prevalence and predictive factors in a New Zealand community sample.

Abstract

The aim of this study was to gather information concerning the relationship between several of the main factors, as derived from existing research, associated with bulimia nervosa symptoms, in a New Zealand Community sample.

Two hundred and forty three women aged between 17 and 25 were recruited from the Christchurch community. They answered a questionnaire which was designed to measure eating disorders (The Bulimia Test), restraint, body shape perception, depression (The Beck Depression Inventory), general psychiatric symptoms, life stress and cognitive distortions. The questionnaire recorded information about their height, weight, and personal circumstances. The majority of the subjects were from university, while the rest were from vocational courses, working or unemployed.

The median Body Mass Index score was 21.9, slightly lower than recent New Zealand normative data (23.5) for this age group. By these norms, 8% were over weight and 1% were obese. The median score on the Bulimia Test was 52.5 (range 34-133). By test norms, 2.4% were bulimic and a further 2.4% sub-clinically bulimic. These figures are consistent with recent epidemiological data for Christchurch, NZ. On revised DSM III-R Bulimia Test criteria the rate of bulimia nervosa went down to 0.4%, with a further 2.9% presenting as sub-clinically bulimic. On another question relating the degree to which their eating habits interfered with their every day functioning, 21 % said "sometimes " and 2.5% said "always". University students scored slightly lower than non-students on the depression score. BDI depression scores ranged from 1 to 41 (median 6) with 18% indicating mild depression, 26% having moderate depression and 15% potentially serious depression. The median score on the cognitive distortions test was 55 (range from 24 to 104). Using a cut-off score (61) previously found to be predictive of a clinical diagnosis of bulimia, 21% of the sample had levels of cognitive distortion predictive of an eating disorder.

Correlational and multiple regression analyses suggested that the two best predictors of eating disorder status were the cognitive distortions score (relating to weight and appearance), followed by restraint, rather than measures of depression, stress or body image distortion. Results were discussed in light of these findings.