The study focused on 1,376 American Indians ranging in age from 14 to 39 who are part of the Strong Heart Family Study, an ongoing project examining cardiovascular health among U.S. tribal populations that began in the 1980s. At the start of the current study, none of the young people had signs of cardiovascular disease. But when they had ultrasounds of the carotid artery, the main vessel supplying blood and oxygen to the brain, researchers discovered that 5.2 percent of the participants had subclinical atherosclerosis — a prevalence they described as “unexpectedly high” in their presentation. During a follow-up period of about two decades, 8.7 percent of the study participants experienced cardiovascular disease events like heart attacks and strokes. The risk for these events was 85 percent higher for people with subclinical atherosclerosis. “This is the first study to document this phenomenon,” says lead study author Jessica Reese, PhD, of the Center for American Indian Health Research at the University of Oklahoma Health Sciences Center in Oklahoma City. While the results are preliminary, and haven’t been published in a peer-reviewed medical journal, the findings suggest that screening for atherosclerosis may need to start at young ages among American Indians, Dr. Reese says. That’s because interventions that help prevent atherosclerosis and slow its progression in older individuals might also help young people. “Some modifiable risk factors that we have observed in older adults, such as sedentary lifestyle and unhealthy diet, may also contribute to the development of atherosclerotic plague among adolescents,” Reese says.
Heart Health Disparities and Barriers to Care
Atherosclerosis develops when plaque — deposits of debris and fatty substances — accumulates inside artery walls, causing them to thicken and stiffen and pump blood less effectively. Plaque deposits can also form clots that break off and travel to arteries supplying the heart or the brain, where blockages can then cause heart attacks or strokes. Risk factors for atherosclerosis among American Indians are similar to what’s seen in other racial and ethnic groups in the United States, says Timian Godfrey, DNP, an assistant clinical professor at the University of Arizona who works as an emergency medical care provider for Tribal Health based in Scottsdale. These risk factors include high blood pressure, diabetes, elevated cholesterol levels, obesity, and smoking, says Dr. Godfrey, who wasn’t involved in the study. In theory, these risk factors can be addressed by lifestyle changes like eating healthier foods, exercising more, and not smoking, Godfrey says. But in reality, American Indian adolescents and young adults face unique barriers to following a healthy lifestyle and accessing preventive care that may contribute to their increased risk of subclinical atherosclerosis, Godfrey says. “When looking at health disparities in American Indian adolescents and young adults, the influence of structural racism and social determinants of health cannot be ignored,” Godfrey says. “Longstanding systemic inequities in the environment, food systems, access to health services, and societal factors have largely contributed to poor health outcomes in American Indian populations.”
Putting the Risk in Context
Heart disease is the leading cause of death among American Indian or Alaskan Native people living in the United States, according to the Centers for Disease Control and Prevention (CDC). The study results suggest that subclinical atherosclerosis may play a bigger role in this risk than previously thought, Reese says. The proportion of young American Indians who experienced cardiovascular disease events during the study — 8.7 percent — is much higher than the prevalence for young people in the U.S. population as a whole, Reese notes. One study published in June 2019 in Circulation, for example, put the prevalence of these events among U.S. adults 20 to 39 years old at 1.1 percent for men and 1.4 percent for women. Historically, American Indians under age 65 have also been more likely to die prematurely from events like heart attacks and strokes than people from other racial and ethnic groups, Reese says. One report from the CDC dating back to 2004, for example, put premature mortality rates from cardiovascular disease events at 36 percent among American Indians, compared with 32 percent for Black Americans and 15 percent for white Americans. Earlier detection of cardiovascular risk factors, and earlier intervention, will be necessary to help turn these trends around, Godfrey says. “Prioritizing a healthy lifestyle can make a significant impact on atherosclerotic changes in American Indian adolescents and young adults,” Godfrey says. “Policies and advocacy efforts shaping social determinants of health like nutrition, physical activity, and tobacco exposure are important in strengthening the prevention of subclinical atherosclerosis in American Indian youth.”
