MONDAY, June 30, 2008 (HealthDay News) -- More than 6 million children in the United States have a condition called nonalcoholic fatty liver disease (NAFLD), which can boost their odds for heart disease, researchers report.
NAFLD results from oily droplets of triglycerides forming in liver cells. In some children, this can lead to cirrhosis and liver failure and the need for liver transplant. In others, NAFLD can help cause diabetes, high blood pressure and high cholesterol, all of which are linked to cardiovascular trouble.
"NAFLD is now the most common chronic liver disease in children," noted lead researcher Dr. Jeffrey Schwimmer, an associate professor of pediatrics at the University of California, San Diego. "We believe that children with NAFLD are at greatest risk for heart disease and diabetes," he said.
The disease is now so common that between 9 percent and 10 percent of children in the United States have NAFLD, Schwimmer said. "About 80 percent of children with NAFLD are overweight," he said.
Approximately 5 percent of these children will develop severe advanced liver disease, Schwimmer said. The majority of children with this condition are at risk for developing cardiovascular risk factors leading to what's known as the metabolic syndrome, he added. Metabolic syndrome boosts heart risks and includes three of these symptoms: abdominal obesity, high blood triglyceride levels, lower levels of "good" HDL cholesterol, elevated blood pressure and elevated fasting blood glucose
The report is published in the July 8 issue of the journal Circulation.
In the study, Schwimmer's team looked at 150 overweight children diagnosed with NAFLD, comparing them with 150 overweight children without the condition. Children ranged from five to 17 years of age with an average age of 12.7 years.
The team found that children with NAFLD had higher levels of blood sugar, insulin, total cholesterol, LDL cholesterol (the bad cholesterol), triglycerides and higher blood pressure compared with children without NAFLD.
In addition, children with NAFLD had lower levels of HDL cholesterol (the good cholesterol), Schwimmer's group found.
"Overweight children with NAFLD were three times as likely to have metabolic syndrome as overweight children without NAFLD," Schwimmer said. "Overweight children with metabolic syndrome, compared to overweight children without metabolic syndrome, have five times the odds of having NAFLD," he said.
Schwimmer's group noted that more Hispanic and Asian children had NAFLD compared with white and black children.
NAFLD is becoming more common among overweight children and is associated with type 2 diabetes and the metabolic syndrome, which puts children at risk for cardiovascular disease and type 2 diabetes.
"Since 2002, the numbers of children we are seeing with NAFLD and the severity of the disease we are seeing have both increased a great deal," Schwimmer said.
Currently, there are no treatments for NAFLD, Schwimmer said. "Lifestyle therapy is the main method of treatment. Some people can have tremendous improvement in their disease with nutrition and physical activity, but that's not true for everybody," he said.
Overweight or obese children who should be screened for NAFLD include those with a family history of liver disease or cardiovascular disease or diabetes, Schwimmer said.
Most people with chronic liver disease will not have symptoms, Schwimmer said. "Approximately 25 percent of people with chronic liver disease have symptoms. These can be vague and include abdominal pain and fatigue," he said.
"There is a sign that some children will have," Schwimmer said. "There is a darkening and thickening of the skin around the neck called acanthosis nigricans. Many children with NAFLD will have at least some degree of acanthosis nigricans," he said.
Dr. Sarah de Ferranti, director of the Preventive Cardiology Clinic at Children's Hospital Boston, labeled NAFLD as yet another serious consequence of the obesity epidemic among children.
"The well-publicized pandemic of pediatric obesity has many consequences," de Ferranti said. "Nonalcoholic fatty liver disease is a less well known, but increasingly appreciated, late complication of severe obesity that can lead to cirrhosis and liver failure," she said.
"Pediatric practitioners should be aware of the need to look for a broad range of obesity complications, and families will need to understand that obesity is not purely a cosmetic issue but has important health consequences," de Ferranti said. "Unless we address this pediatric obesity aggressively, we will be facing high rates in young adults of not only diabetes and heart attack, but also liver disease and the demand for liver transplant."
For more about NAFLD, visit the American Academy of Family Physicians.