Severely obese children have lipoprotein profiles that signal early risk of cardiovascular disease and the metabolic syndrome, according to a study presented at the American Heart Association's Sixth Annual Scientific Conference on Arteriosclerosis, Thrombosis and Vascular Biology.
"The message is urgent about the importance of prevention of cardiovascular disease in childhood. Lifestyle modification with appropriate diet and exercise can reduce cardiovascular risk in children," said lead author Daniel L. Preud'Homme, M.D., associate professor of medicine at the Wright State University School of Medicine and director of the lipid clinic at The Children's Medical Center, both in Dayton, Ohio.
Lipoproteins transport cholesterol throughout the body. Lipoprotein subclasses and the size of lipoprotein particles can be measured by a test that uses nuclear magnetic resonance (NMR) spectroscopy to provide a more detailed lipid profile than standard lipid panels.
High-density lipoprotein (HDL) is sometimes called "good" cholesterol because it returns cholesterol to the liver where it can be eliminated. Low-density lipoprotein (LDL) is often called "bad" cholesterol because of its association with clogged arteries and increased cardiovascular risk. In addition, studies have linked smaller LDL particle size with higher risk.
The study focused on 160 children, average age 12.6 years, who were evaluated at Wright State University's pediatric lipid clinic. Severe (morbid) obesity was defined as body mass index (BMI) of 36 and above, which is higher than that of 99 percent of children the same age and gender (the 99th percentile on BMI growth charts).
Of the children, 53 percent were boys and 47 percent were girls. Seventy percent were categorized as white/other, including four children who were Hispanic, Native American or Asian, while 30 percent were black.
They found differences between black and white children in the sizes and subclasses of the lipoproteins.
"The obese white children have significantly higher early risk of cardiovascular disease than the obese black children according to this test," Preud'Homme said.
This was an unexpected finding because other studies have found the opposite to be true in the general population for a variety of risk factors including high blood pressure and type 2 diabetes, he said.
In this study, differences between the two groups include:
- Low levels of "good" large HDL particles were found in 46 percent of white children compared to 29 percent of black children, representing significantly increased cardiovascular risk.
- High levels of large very low-density lipoprotein (VLDL) were identified in 62 percent of white children compared to 31 percent of black children, also a significant increase in risk.
- LDL pattern B – a lipid profile with an unusually high number of small, dense LDL particles that is thought to confer higher cardiovascular risk – was found in 45 percent of white children compared to 19 percent of black children.
- Obese white children were shown to have a higher risk of experiencing the dyslipidemia associated with metabolic syndrome than obese black children. Fifty-three percent of white children were identified with two or more blood lipoprotein levels associated with metabolic syndrome (small LDL, low numbers of large HDL and increased VLDL) compared to 21 percent of black children.
Lipid abnormalities are part of a cluster of conditions comprising the metabolic syndrome. Metabolic syndrome is also closely associated with a generalized metabolic disorder called insulin resistance, in which the body cannot efficiently use insulin. People with the metabolic syndrome are at increased risk of coronary heart disease, stroke, peripheral vascular disease and type 2 diabetes.
The study found no gender differences for lipoprotein variables.