WEDNESDAY, Aug. 9, 2017 (HealthDay News) -- Children from poor families are more likely than their richer peers to show signs of narrowing in the neck arteries -- hinting they could face a heightened risk of heart disease as adults.
That's the finding of a new study that followed children from nearly 1,500 Australian families.
The study builds on evidence that heart disease risk can start to take shape at a young age.
It also adds another layer: Social disparities in heart disease risk may begin early in life, too, said Dr. Gregg Fonarow.
Fonarow, who was not involved in the study, is co-director of preventative cardiology at the University of California, Los Angeles.
It's well-known that poor adults face a higher heart disease risk than their more-affluent counterparts, Fonarow said. But it hasn't been clear whether kids from poor families are more likely to show early warning signs of unhealthy arteries.
"These findings suggest that socioeconomic status during the first 10 years of life may impact the development of subclinical atherosclerosis," Fonarow said.
Subclinical atherosclerosis refers to an early stage of narrowing in the arteries. It's considered an indicator of an increased risk of heart disease down the road.
The new study, published online Aug. 9 in the Journal of the American Heart Association, used noninvasive imaging to look at kids' carotid arteries.
The carotid arteries run through the neck, supplying blood to the brain, and are easy to study using ultrasound. A substantial thickening in the walls of those arteries can signal subclinical atherosclerosis.
Overall, the study found, 11- and 12-year-olds from poor families showed more thickening in the carotid artery walls.
On balance, their blood vessels looked more than eight years "older" than their actual age, the researchers reported.
Does that mean they are in danger of premature heart attacks and strokes? It's not clear, said the study's senior researcher, David Burgner of Murdoch Children's Research Institute, in Parkville, Australia.
In adults, carotid artery thickening is linked to a heightened risk of future heart attack and stroke, Burgner said.
Whether that's true of kids is unknown, he added.
On the other hand, studies do show that atherosclerosis, in general, can begin at a young age and progress over a lifetime.
So it's "very plausible," Burgner said, that the carotid narrowing seen in this study could be a red flag.
Still, the study can't prove a direct cause-and-effect relationship. More research is needed to know for sure, Burgner said.
The findings are based on children from 1,477 families who were followed from infancy to age 11 or 12. Every two years, the kids underwent ultrasound to measure the thickness of the right carotid artery wall.
Kids who were in the top 25 percent for carotid wall thickness were considered "higher risk." That's because adults who fall into that category have roughly double the risk of heart disease and stroke, versus adults in the bottom 25 percent, the researchers noted.
Overall, the study found, 11- and 12-year-olds from poor families were 46 percent more likely to fall into the higher-risk group, compared with those from high-income families.
Disadvantaged kids were more likely to be overweight, have high blood pressure or be exposed to secondhand smoke. But those factors did not explain the artery findings, Burgner said.
What is the explanation?
Burgner speculated that infections might play a role.
"Disadvantaged children get more infections, and tend to do so earlier in life," he said. That matters, he explained, because frequent infections can drive low-grade inflammation in the body -- and that can contribute to atherosclerosis.
Fonarow said more research is needed to understand why low-income kids are more vulnerable to narrowing in the carotid arteries.
But for now, Burgner said, it's already clear that kids benefit from a healthy diet, regular exercise, and keeping their weight and blood pressure at normal levels.
So it's important to make nutritious food and opportunities to exercise more accessible to low-income families, he said.
"More broadly," Burgner added, "reducing social inequality is critical."
The American Heart Association has advice on keeping kids healthy.