The results may help doctors identify high-risk children and prevent further cardiovascular damage before it is too late, say UK researchers.

“This is the stage of life where changes to a person’s body are potentially reversible,” says lead researcher Faisal Khan at the University of Dundee, UK. “If you leave it until their 30s or 40s, it is much harder.”

Khan and his colleagues studied the lining of tiny blood vessels, or endothelium, in 158 Scottish children, aged 11 to 14. Within this group, 20% of children showed impaired endothelial activity.

Though poor lining health was associated with elevated amounts of abdominal fat and diabetic-like blood sugar levels, almost none of the children fell outside the normal range for either trait.