The size of a child's wrist may offer clues to future heart health.
A study in this week's Circulation found that overweight children with larger wrist bone measurements had higher insulin resistance, a risk factor for developing heart disease. It occurs when the body makes insulin but can't use it efficiently to break down blood sugar.
"Wrist circumference mirrors insulin resistance levels," says senior study author Raffaella Buzzetti, a professor in clinical sciences at Sapienza University of Rome.
"One of the major priorities of clinical practice today is the identification of young people at increased risk for insulin resistance. This is a very, very strong link," Buzzetti says.
In the study, the wrist circumferences of 477 overweight and obese kids and teens (average age 10) were measured with a tape measure; 51 also had nuclear magnetic resonance imaging. This allowed researchers to measure the wrist bone alone. All of the children also had blood tests to measure insulin levels.
There was a much stronger relationship between wrist bone circumference and the level of insulin in the blood than the relationship between body mass index (BMI) and insulin levels, the researchers report. BMI is a number based on weight and height that doctors use to estimate whether a person is normal weight, underweight or overweight. BMI is also an indicator of diabetes and heart risk.
Although excess body fat is linked to heart disease risk, this is the first evidence that suggests a larger wrist circumference flags it, too, says Suzanne Steinbaum, director of women and heart disease at Lenox Hill Hospital in New York City.
Steinbaum says it makes sense because it's known that an increased amount of insulin in the system acts as a growth factor on bone.
"We talk about the concept of being big-boned, but does that imply anything? What this is saying is that there might be some correlation between wrist circumference and insulin resistance," she says.
More studies are needed before doctors can use wrist measurements to predict heart disease in youngsters, Steinbaum says.
She says inactivity and poor diet are at the root of a dismaying increase in the number of overweight and obese children.
"What's very sad is that we have to do this at all -- that we have to do more studies to figure out heart disease risk in our children," she says.
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