Autism spectrum disorders and low body weight: is there really a systematic association?

OBJECTIVE

To examine the relationship between autism spectrum disorders and low body weight.

METHOD: The effect of maladaptive social and communicative behavior as well as stereotyped features on the normative body mass index (BMI) was analyzed in 103 subjects with autism or Asperger syndrome. Statistics were controlled for medication, neurological signs, overactivity, and general intelligence.

RESULTS

Twenty-eight percent of the male individuals had a BMI in the fifth percentile or below. Except for hyperactive behavior, none of the predictors showed a significant association with BMI. None of the subjects met diagnostic criteria for anorexia nervosa.

DISCUSSION: Although low body weight is often present in male subjects with autism or Asperger syndrome, results indicate that this link is inconsistent and partly mediated by hyperactivity. The co-occurrence of autism spectrum disorders and anorexia nervosa is probably due to chance.