Children With Newly Diagnosed Epilepsy Often Obese or Overweight

Pauline Anderson

September 03, 2009

September 3, 2009 — Almost 40% of children with newly diagnosed epilepsy are overweight or obese — a rate that is more than double that expected in a normally distributed population, new research suggests.

Doctors should be aware of this comorbidity, particularly in adolescents, choose antiepileptic medication accordingly, and introduce strategies to prevent obesity in their young patients with epilepsy.

The report, led by Tracy A. Glauser, MD, professor of pediatrics and neurology at Cincinnati Children's Hospital Medical Center in Ohio, is published in the September 1 issue of Neurology.

The study examined 251 children, aged 2 to 18 years, who were newly diagnosed with epilepsy but were still untreated and who attended a seizure clinic at Cincinnati Children's Hospital Medical Center between July 7, 2003 and October 30, 2006.

Researchers compared the obesity rate of this population with published national standards (Centers for Disease Control and Prevention growth curves) and with a regional healthy control group.

The healthy control group consisted of 597 subjects from the Cincinnati Children's Genomic Control Cohort initiative, a sample representative of the region in terms of race, ethnicity, sex, and socioeconomic status. Patients in the control group were growing and developing normally at the time of enrollment.

Epilepsy Type

For the epilepsy group, researchers accessed information on type of seizure/epilepsy (classed according to the International League Against Epilepsy's Classification for Seizure, Epilepsies, and Epilepsy Syndromes), epilepsy etiology, stimulant use, and insurance status.

Most epilepsy patients had partial-onset seizures (59.8%) and idiopathic epilepsy (74.5%) and were not taking medication (72.5%). Of those who took medication, 8.4% used stimulants and 19.1% were taking other drugs, mostly antiallergens.

To determine weight, researchers used age-adjusted body mass index (BMI) Z-scores (a continuous variable useful in monitoring changes in obese patients) and BMI percentiles. These percentiles were classified as obese (top 95th percentile), overweight (between the 85th and 95th percentiles), healthy weight (between the 10th and 85th percentiles), and underweight (below the 10th percentile).

Overall, in the epiliepsy group, 38.6% of the children were either obese (19.9%) or overweight (18.7%), and in the control group, 28.4% were obese (13.7%) or overweight (14.7%).

About 10% of patients taking a stimulant psychotropic were obese, as were close to 20% of patients not taking this medication.

More Adolescents Obese

Older children — especially those around 15 years of age — appeared to be especially prone to being overweight. Overall, 27.0% of adolescents and 17.6% of preadolescents were obese.

The study found that insurance status, race, and sex were not significantly associated with being overweight or obese.

Childhood obesity is increasingly recognized as an important public-health issue. National surveys show that 17.1% of children are obese. These youngsters are at increased risk for heart disease, hypertension, type 2 diabetes, and other chronic conditions that, if left untreated, can carry into adulthood.

Obesity in children with epilepsy is particularly concerning because of the weight effects and endocrine changes associated with commonly used antiepileptic medications, such as valproic acid, carbamazepine, gabapentin, and vigabatrin.

Still Many Unanswered Questions

In an accompanying editorial, Edwin Trevathan, MD, MPH, and William H. Dietz MD, PhD, from the Centers for Disease Control and Prevention in Atlanta, Georgia, point out that the higher obesity rates among children with epilepsy in the study can't be due to epilepsy drugs because these youngsters were obese before starting medication.

There are many questions still to be answered, they write: "Do some of the metabolic abnormalities associated with obesity predispose to seizures, are changes in appetite or physical activity harbingers of impending epilepsy, or is there a common pathway that fosters both obesity and seizures?"

Neurologists may be reluctant to discuss weight with patients, but raising the issue with children and parents increases the likelihood that efforts at weight control will be initiated. Such a discussion might be easier if doctors ask patients or families for permission to discuss weight problems and if they use the term "overweight" or "elevated BMI" instead of "obese," they write.

The researchers of the study have disclosed no relevant financial relationships. Dr. Trevathan and Dr. Dietz are full-time employees of the Centers for Disease Control and Prevention, and Dr. Trevathan serves on the editorial boards of Neurology, Disability and Health Journal, and the Journal of Developmental Origins of Health and Disease.

Neurology. 2009;73:654-655 and 658-664. Abstract, Abstract


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