Young children with a persistently low body mass index (BMI) may be at greater risk for developing anorexia nervosa in adolescence, according to a new population-based study published in the Journal of the American Academy of Child and Adolescent Psychiatry. The findings apply to girls as young as 4 years old and boys as young as 2.
In addition, the study found that a persistently high BMI in childhood may be a risk factor for future development of bulimia nervosa, binge-eating disorder, and purging disorder.
First author Dr. Zeynep Yilmaz says that although eating disorders are psychiatric in nature, the findings highlight the need to also consider metabolic risk factors alongside psychological, sociocultural and environmental components.
“The differences in childhood body weight of adolescents who later developed eating disorders started to emerge at a very early age — way too early to be caused by social pressures to be thin or diet,” says Yilmaz, an assistant professor of psychiatry and genetics at the Center of Excellence for Eating Disorders in the University of North Carolina (UNC) School of Medicine.
“A more likely explanation is that underlying metabolic factors that are driven by genetics could predispose these individuals to weight dysregulation. This aligns with our other genetic work that has highlighted a metabolic component to anorexia nervosa.”
“Until now, we have had very little guidance on how to identify children who might be at increased risk for developing eating disorders later in adolescence. By looking at growth records of thousands of children across time, we saw early warning profiles that could signal children at risk.”
The findings also reveal the multi-factorial composition of eating disorders, as well as the need to develop early detection tools that could be used as part of routine checks by all pediatricians, says corresponding author Dr. Nadia Micali, professor at University of Geneva Faculty of Medicine in Switzerland and head of Geneva University Hospitals’ Division of Child and Adolescent Psychiatry.
“Indeed, the earlier the problem is identified, the better it can be managed, especially if support is provided to the family as a whole, rather than just the individual,” Micali says.
For the study, researchers analyzed data from 1,502 individuals who participated in the Avon Longitudinal Study of Parents and Children in the UK.
“Clinically, this means that pediatricians should be alert for children who fall off and stay below the growth curve throughout childhood,” says coauthor Dr. Cynthia Bulik, a distinguished professor of eating disorders from the University of North Carolina School of Medicine (UNC).
“This could be an early warning sign of risk for anorexia nervosa. The same holds for children who exceed and remain above the growth curve — only their risk is increased for the other eating disorders such as bulimia nervosa and binge-eating disorder.”