Influence of premorbid BMI on clinical characteristics at presentation of adolescent girls with eating disorders

Background: Considering the prevalence of obesity in society it can be expected that some adolescents with an eating disorder (ED) start weight loss from an overweight and present at a near-normal weight. Presently, the influence of premorbid BMI on clinical characteristics of adolescent girls presenting with an ED has ben studied. Method: Premorbid growth charts were available for 275 postmenarcheal adolescent girls presenting with an ED (anorexia nervosa = 27, (subthreshold) bulimia nervosa = 9, restrictive EDNOS = 239). Initial assessment included measurement of weight and length, physical examination, blood sampling and administration of the Eating Disorder Examination-Questionnaire youth version (EDE-Q). Results: Despite greater weight loss girls with a high premorbid body mass index (BMI) had a higher BMI at presentation compared to those with a lower premorbid BMI. Although not underweight some presented with clinical and laboratory signs of starvation. These signs were related to not only low BMI but also to rapid and large weight loss. Their EDE-Q scores did not differ from those of girls who presented with an underweight. Conclusion: Girls with a restrictive ED and premorbid overweight may present with a near-normal BMI. They can nevertheless be medically compromised and have eating disturbed cognitions at the level of underweight girls. They should not be regarded as having a less severe ED but merit full assessment and a start of treatment.