June 30, 2008 -- A little-known form of liver disease may be a warning sign
of impending heart disease in overweight and obese children.
A new study shows non-alcoholic fatty liver disease (NAFLD) is associated
with more serious heart disease risk factors in obese children, such as high
cholesterol, elevated fasting glucose and insulin levels, and high blood
pressure, compared with obese children without fatty liver disease.
Non-alcoholic fatty liver disease affects more than 6 million children in
the U.S. and is the most common cause of liver disease in children. The
condition is diagnosed by confirming the presence of oily droplets in liver
cells via a tissue biopsy.
This type of fatty liver disease is also associated with metabolic syndrome,
a clustering of risk factors for heart disease and type 2 diabetes.
"Our results demonstrate that obese children and adolescents with a
definitive diagnosis of NAFLD have a more severe cardiovascular risk profile
than their age, sex, and BMI-matched peers," says researcher Jeffrey
Schwimmer, MD, associate professor of pediatrics at the University of
California, San Diego, in a news release.
"Overweight children age 8 or older and especially those with symptoms
of metabolic syndrome should be screened for NAFLD," says Schwimmer. "I
think many parents have not ever heard of NAFLD, and many physicians are not
aware of its prevalence and severity in children. Identification of NAFLD in a
child should prompt counseling that addresses nutrition, physical activity and
avoidance of smoking."
Liver Disease Tied to Heart Risk
In the study, published in Circulation: Journal of the American Heart
Association, researchers compared heart disease risk factors among 150
overweight children with non-alcoholic fatty liver disease and 150 overweight
children without NAFLD.
The results showed that children with fatty liver disease had significantly
higher fasting glucose, insulin, total cholesterol, and blood pressure than
children of a similar weight and age without NAFLD.
Children with fatty liver disease also had significantly lower levels of HDL
"good" cholesterol than the others.
Researchers found NAFLD was more prevalent among Hispanic and Asian children
than white and black children, and children with metabolic syndrome were five
times more likely to have NAFLD than other overweight or obese children.
Schwimmer says the results suggest that fat accumulation in the liver may
play a more important role than obesity itself in determining the risk of
weight-related health risks. The treatment of fatty liver must focus on
preventing end-stage liver disease. However, the presence of NAFLD also appears
to identify children and adolescents at high risk of subsequent cardiovascular
disease. Treatment should also include heart disease prevention