SAN ANTONIO, March 1 - In the first study to examine nationwide trends in sudden cardiac death (SCD) among the young, researchers have found that the number of adolescents and young adults who die from sudden cardiac arrest has gone up in the past decade.
Today's report comes from the American Heart Association's 41st Annual Conference on Cardiovascular Disease Epidemiology and Prevention. The yearly death totals from sudden cardiac death for teens and young adults climbed from 2,719 in 1989 to 3,000 in 1996 - a jump of about 10 percent.
"Explaining these trends will require more scientific studies. But we can speculate that some of the increase may be related to the increased prevalence of cardiovascular risk factors, such as obesity among adolescents. It may also be due to a poor rate of recognizing SCD in younger patients and applying cardiopulmonary resuscitation," says Zhi-Jie Zheng, M.D., Ph.D., lead author of the study and an epidemiologist in the Cardiovascular Health Branch of the National Center for Chronic Disease Prevention and Health Promotion, at the Centers for Disease Control and Prevention (CDC) in Atlanta.
In analyzing national death certificate data for people aged 15-34, researchers found that of the 23,320 individuals who died suddenly of cardiac arrest between 1989 and 1996, 71 percent were men, and 29 percent women. Though the rate of SCD was twice as high among men than in women, the new numbers represent a 30 percent increase in SCD over the eight-year period among adolescent and young adult females. SCD among males increased by 10 percent.
"Unfortunately, we can't explain why there is a large increase in SCD among this age group of young women," says Zheng. "However, combined with the findings of our previous study in an older group of women, we think this trend is real."
In a study presented at the American Heart Association's Scientific Sessions 2000 meeting last November, Zheng reported that women aged 35-44 had a 15 percent increase in SCD during the same period.
A breakdown of the figures shows that 21 percent of the deaths were among persons aged 15-24, and 79 percent were among persons aged 25-34, says Zheng. The death rates in people aged 15-34 appear to increase proportionately with each year of advancing age. Death certificates examined in the study showed that 36 percent of young SCD victims suffered from ischemic heart disease, the major cause of heart attacks, in which blood supply to the heart is restricted. Another 34 percent of the victims had arrhythmia (irregular heartbeat) or cardiomyopathy (deterioration of the heart muscle).
"The presence of any symptoms of a heart attack increases the likelihood of sudden death," Zheng says. "But it must be emphasized that, for many people, sudden death is the first manifestation of heart disease."
Zheng emphasizes that SCD is relatively rare in the young, and is often preventable. Young people at high risk of SCD can often be identified by a family history of sudden cardiac death, one of the most important predictors of SCD in younger people, he notes. Other ways to predict SCD risk include EKG indications of enlarged heart size, increased thickness of the heart wall, previous "silent" heart attack or an abnormal stress test.
"In the United States as a whole, the death rate from heart disease has declined during the past 50 years, but due to an aging population, the total number of heart disease deaths actually increased from 1900 to 1980, then leveled off from 1980 to 2000," Zheng notes. "With that in mind, the most striking aspect of our report is that this specific young age group had both an increase in the total number of SCD deaths and in the death rate for SCD between 1989 and 1996," he says.
This study accentuates the need for younger people to adopt lifestyle choices - such as adequate physical activity and healthy eating habits - that reduce their risk for heart attacks, adds George A. Mensah, M.D., chief of the Cardiovascular Health Branch of the National Center for Chronic Disease Prevention and Health Promotion at the CDC, who contributed to the report.
"It's not just old folks and men who fall prey to heart attacks and sudden cardiac death. Women and young adults in general should be aware of the risks, too," Mensah says.
Other researchers participating in the study include Janet B. Croft, Ph.D., and Wayne H. Giles, M.D.
CONTACT: Carole Bullock or Darcy Spitz, AHA News Media Relations, San Antonio Marriott Rivercenter, Ph. (210) 554-6255