Heart damage linked to obesity in kids

A big, strong heart is important to staying healthy and active. But hearts can grow too big. Now, a study finds that obese children as young as eight often have enlarged, potentially unhealthy, hearts.

An enlarged heart won’t kill someone. Indeed, elite athletes who are exercising their muscles — including their heart muscle — may end up with a big, powerful heart. But in couch potatoes, an enlarged heart can be a sign of developing heart disease. And that’s what the new study uncovered.

Among very overweight kids, “Even the youngest children in our study, who were only 8 years old, had evidence of heart disease,” notes Brandon Fornwalt. He works at the Geisinger Health System in Danville, Penn. There, he studies how muscle in the heart expands and contracts to pump blood throughout the body.

His team used magnetic resonance imaging, or MRI, to take pictures of 40 kids’ hearts. The children were all between 8 and 18 years old. Half were obese, meaning overweight to an unhealthy degree. The rest were at a healthy weight. From the MRI images, the scientists could see that 40 percent of the obese children had enlarged hearts that interfered with how well blood pumped throughout their bodies. No healthy-weight child had such problems.

Obese children also had changes to their left ventricle. That’s the lower left chamber of the heart. Its job is to pump oxygen-rich blood out to the rest of the body. Of the human heart’s four chambers, the left ventricle is thickest. But obese children had thicker left ventricles compared to those in normal-weight children.

Both an enlarged heart and thicker heart tissue can signal heart disease. In adults, such heart changes have been linkedwith earlier death, Fornwalt notes. That’s why he finds the new results so worrisome. That his team witnessed such changes in even 8-year-olds implies that obese young children may have heart disease.

Linyuan Jing is a biomedical engineer on his team at Geisinger. She presented their new findings on November 10 in Orlando, Fla., at the American Heart Association’s annual scientific meeting.

Despite these troubling findings, there’s some good news. The share of U.S. children who are obese is not continuing to mushroom. That means that the condition is stable. How common something is tends to be known as its prevalence. And the prevalence of childhood obesity has remained flat at around 17 percent since 2003. That’s according to new data reported in November by scientists with the National Center for Health Statistics in Hyattsville, Md.

Still, Fornwalt points out, that rate is more than triple the obesity prevalence seen among kids in the 1960s. “As a society, we need to find ways to make sure these rates start dropping,” he says. He adds that he and others hope that with appropriate treatment, doctors can reverse heart disease in obese children. But, he adds, how this might be done still needs to be studied.

Reversing the childhood obesity epidemic begins at home and in the schools, Fornwalt says. “We need to change our culture to encourage healthy lifestyles for our children,” he says. “And it’s going to take a lot of work to do this.”

Power Words

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couch potato    Slang for people who get very little exercise, often because they spend much of their leisure time sitting around, usually watching television.

epidemic  A widespread outbreak of an infectious disease that sickens many people (or other organisms) in a community at the same time. The term also may be applied to non-infectious diseases or conditions that have spread in a similar way.

magnetic resonance imaging (MRI)  An imaging technique to visualize soft, internal organs, like the brain, muscles, heart and cancerous tumors. MRI uses strong magnetic fields to record the activity of individual atoms.

obesity  Extreme overweight. Obesity is associated with a wide range of health problems, including type 2 diabetes and high blood pressure.

oxygen  A gas that makes up about 21 percent of the atmosphere. All animals and many microorganisms need oxygen to fuel their metabolism.

prevalence The degree to which something is common or widespread. An example is the percentage of a population that is affected with a particular disease at a given time.

statistics The practice or science of collecting and analyzing numerical data in large quantities and interpreting their meaning. Much of this work involves reducing errors that might be attributable to random variation. A professional who works in this field is called a statistician.

ventricle  One of two sections of the heart that pump blood out to the body.