Jan. 11, 2001-- It's been known for some time that obese adults have high levels of C-reactive protein (CRP), a substance that tips off doctors to the presence of inflammation inside the body. CRP levels -- like cholesterol levels or blood pressure -- are a sensitive predictor of future heart disease. A new study shows that overweight kids also have unusually high levels of this risk-related protein. Researchers say heavy kids are anywhere from three to five times more likely to have it than children of normal weight.
CRP is normally released into the bloodstream as a in response to infection, injury, or disease. In obese adults, it's thought that the presence of CRP is a marker of inflammation occurring in the lining of their arteries, inflammation that may one lead to heart disease.
Researcher Marjolein Visser, PhD, of Amsterdam's Vrije University, says she focused on children in her study because they are less likely than adults to have other things going on that could be causing a rise in CRP levels.
"We know that lifestyle factors like smoking, and diseases like rheumatoid arthritis and heart disease, are associated with increased CRP levels, and, obviously, children rarely have these," Visser tells WebMD. "What our study found is that even in children as young as 8, obesity is associated with this ... chronic inflammation" -- and with the health risks that come along with it.
"Whether you have pneumonia or are in an auto accident, there is this inflammatory response, which is how the body deals with injury," explains Bruce R. Bistrian, MD, chief of clinical nutrition at Beth Israel Deaconess Medical Center and a professor of medicine at Harvard Medical School, both in Boston. "This is beneficial for someone who is only sick for a short period of time. But if the injury response occurs continuously for years and years, there probably will be adverse consequences. And we now know that there is something about obesity that seems to turn on the inflammatory response."
In the Dutch study, published in the January issue of the journal Pediatrics, Visser and colleagues examined CRP levels in a group of just over 3,500 children living in the U.S. They found more cases of elevated CRP in overweight children than in kids of normal weight, and they also determined that being overweight is associated with a higher white blood cell count, confirming the presence of low-grade inflammation.
"We don't know what the health risks of low-grade systemic inflammation are in children, but we know that in adults it has been shown to increase the risk for [heart] disease and diabetes," Visser says. "This inflammation could represent an additional risk factor for future diseases. More study is needed to determine the future health risks are for kids having elevated CRP levels at a young age."
Whatever the long-term health risks turn out to be, Visser says, the findings give overweight children and adults one more reason to try to lose weight.
Bistrian agrees, noting that the inflammatory effects of obesity seem to be reversible with weight loss.
"We have seen in adults that when some weight is lost the inflammatory response diminishes, and if they reach normal weight it goes away altogether," Bistrian says. " Obesity does seem to be turning on this inflammation, and losing weight turns it off."