“Being young” is not a typical risk factor that comes to mind when thinking about potentially dangerous heart conditions, nor do we expect the pediatrician to test for signs of such problems at an annual checkup. But in August, the American Academy of Pediatrics revised its guidelines for the screening, diagnosis and treatment of high blood pressure in youth, the first time these standards have been updated since 2004. The new recommendations simplified the diagnostic procedures for pediatric and adolescent high blood pressure, made the definition for hypertension more similar to adult guidelines and changed the term “prehypertension” to “elevated blood pressure.”
The changes make it easier for doctors to spot a growing health threat that has remained hidden because it seems unbelievable: Children and adolescents are increasingly at risk for a heart condition that has always been tied to aging. “We think of someone with hypertension as being that 50-year-old man down the street, but it’s becoming more and more common even in young children,” says Dr. David Kaelber, a pediatric and internal medicine physician at Case Western Reserve University.
The shift hints at problems to come. Hypertension now affects 3.5 percent of children in the United States, or more than 2.5 million people under age 18. That number may seem puny compared with the one-third of American adults with high blood pressure, but Kaelber says it is still worrisome. Rates of high blood pressure in children and adolescents have risen in line with higher rates of childhood obesity, according to epidemiological studies. Without intervention, children with high blood pressure are likely to become adults with high blood pressure, a risk factor for potentially fatal heart disease.
Thousands of studies have linked hypertension in adults to heart attack, stroke, angina and peripheral artery disease. This threat is why adequate screening in young people is so important, says Janet de Jesus, a program officer at the National Heart, Lung, and Blood Institute. “Kids definitely aren’t as healthy as they used to be, and these guidelines are going to be a huge asset to the field.”
For children—and adults—high blood pressure has a variety of causes. Elevated blood lipids can form plaque deposits on arteries, making them narrower and stiffer, which can increase blood pressure. People with higher body weights have more blood, raising the amount of pressure on the walls of arteries. Smoking damages the arteries and leads to inflammation. Kidney problems, obstructive sleep apnea and even medications and thyroid issues can all lead to hypertension.
But high blood pressure isn’t just a sign that something is wrong in the body—it’s a problem in and of itself. Hypertension further damages arteries, and the excess strain on the heart can cause that muscle to grow thicker, which can interfere with its ability to deliver blood, oxygen and nutrients to the body. This cascade of maladies makes hypertension one of the major risk factors for heart disease, according to the American Heart Association, along with obesity, high cholesterol, smoking, physical inactivity and diabetes.
The problem, according to Dr. Carissa Baker-Smith, an epidemiologist at the University of Maryland and the lead data scientist on the new American Academy of Pediatrics guidelines, is that many of these issues go undetected until disaster strikes, at which point it’s far too late to reverse the damage. Baker-Smith pointed to several studies that provided the definitive evidence that although heart disease often may not become apparent until adulthood, its seeds are planted in childhood.
A study called Pathobiological Determinants of Atherosclerosis in Youth in the 1990s and the ongoing Bogalusa Heart Study that began in 1973 have measured the prevalence of narrowed and hardened arteries (atherosclerosis) in adolescents and young adults who died accidentally. Both of these studies revealed strong associations between atherosclerosis—a leading predictor of heart disease in adults—and smoking, cholesterol levels and hypertension. “I really want people, especially parents, to understand that high blood pressure does occur in kids. We’re seeing adult disease in children,” Baker-Smith says.
These results challenge the now-outdated notion that hypertension in kids was primarily the result of congenital conditions that affected the kidney and heart. Although inheritance still accounts for one-fifth of all high blood pressure cases in kids under 18, the remainder are “adult-style” hypertension issues, caused by a convergence of biological and environmental factors. Large epidemiological studies by the Centers for Disease Control and Prevention have documented a rise in systolic blood pressure and in diastolic blood pressure in children between 1988 and 2000, which suggests that the increase in pediatric hypertension isn’t just the result of heightened awareness.
Although adults have a single cutoff for potential blood pressure problems, determining that borderline is more complex for pediatric populations because blood pressure in growing children varies by age, height and sex. Even when doctors were vigilant about screening for blood pressure issues in children, they struggled to interpret those results. “A lot of doctors were very confused,” says Dr. Suzanne Lazorick, a pediatrician and preventive medicine physician at Eastern Carolina University.
Kaelber puts it more starkly. “If you reviewed electronic medical records [for children], you could see blood pressures recorded, but the pediatrician never diagnosed hypertension,” he says. Physicians were unclear about what blood pressure level was too high, so the condition in children went unnoticed.