Very high cholesterol levels in kids may decline over time even without intervention, researchers from the US Centres for Disease Control and Prevention (CDC) have found.
The findings add to an ongoing debate over the importance of high cholesterol in children, and whether cholesterol-lowering drugs are appropriate when changes in diet and physical activity don't cut it.
Such drugs, including statins, are used in adults to reduce the risk of heart disease, a major killer in Western countries. But it isn't clear if they also work for kids.
The new study, published in the journal Pediatrics, shows that after a few years, some youngsters with high cholesterol would no longer be considered for drug treatment according to guidelines.
While this isn't an argument to abandon drug therapy altogether, doctors shouldn't jump the gun when treating kids for cholesterol, the researchers caution.
'Bad cholesterol day'
"Both in kids and in adults there is quite a bit of variability over time," David S Freedman of the CDC told Reuters Health. "People with very, very high cholesterol are likely to be those that are having a bad cholesterol day."
"My paper emphasizes that you probably need at least two or three measurements to screen out kids who are just having a bad day," he added.
"The advice is very well taken," Dr William Neal, who wasn't involved in the study, told Reuters Health.
Last week, a research team led by Neal, of West Virginia University in Morgantown, found that among fifth-graders from West Virginia, as many as one-third with LDL cholesterol levels at or above 160 mg/dL would not be screened under current government guidelines. That led the team to recommend screening all children, although an independent expert said the evidence doesn't support that conclusion.
Neal said he uses statins in children who don't benefit from changing lifestyle, but he virtually never starts medication without doing two cholesterol tests spaced months apart.
"I don't think (the new study) is going to alter my practice or my beliefs much," he said.
Changing cholesterol levels
The CDC researchers examined how cholesterol levels changed over time in a group of more than 6 800 children from Bogalusa, Louisiana. The kids were tested five times on average, and about half of them also had measurements done as adults.
Initial levels of LDL ("bad") cholesterol turned out to be strongly linked to later levels, even after 20 years. But as time went by, the differences in cholesterol between kids tended to shrink, with very high levels slumping and low levels rising. The researchers said the changes might have had nothing to do with diet or exercise changes, although they couldn't say for sure.
The biggest drops were seen in kids who initially had very high cholesterol, landing some in a range that no longer warrants drugs, according to guidelines.
Since 2008, the American Academy of Pediatrics has recommended that drug treatment be considered in cases where LDL cholesterol in the blood is at least 190 milligrams per deciliter (mg/dL); if a parent or grandparent has heart disease or high cholesterol, the threshold is 160 mg/dL.
After four years, cholesterol levels had fallen below that threshold 60 percent of the time in kids that initially landed above it, the new report shows.
Routine screening not recommended
"Although for the most part children with extremely high LDL cholesterol levels had high levels at reexamination," the researchers write, "the changes in LDL cholesterol levels that occurred between examinations would have altered the recommended dietary or pharmacologic interventions for many children."
The fundamental question, however, is what to do with those kids who have high cholesterol.
As Dr Michael L. LeFevre, of the University of Missouri in Columbia, told Reuters Health last week, "Unfortunately, there is no evidence that starting a ten-year-old on cholesterol-lowering drugs will prevent heart disease 40 years later."
For that reason, the US Preventive Services Task Force, a federal expert panel of which LeFevre is a member, currently doesn't recommend routine cholesterol screening in any children. - (Reuters Health, July 2010)