The lifetime risk for developing coronary heart disease (CHD) has been estimated for the first time by researchers at the National Heart, Lung, and Blood Institute's Framingham Heart Study. The risk is high: one out of every two men and one out of every three women aged 40 and under will develop CHD. At age 70, the risk is still high: one out of every three men and one out of every four women will develop CHD in their remaining years of life. The paper is published in the January 9 issue of the journal Lancet.
"This study shows why it is so important for adults of all ages to take steps to prevent heart disease," says Claude Lenfant, M.D., NHLBI Director. "Even young adults should know their cholesterol and blood pressure numbers, eat in a heart-healthy way, be physically active and watch their weight to reduce their lifetime risk of the disease."
Heart disease is the number one killer of Americans. The most common form of heart disease is CHD. It affects 12 to 13 million Americans. It occurs when the coronary arteries become narrowed or clogged and cannot supply enough oxygen-rich blood to the heart. CHD can lead to chest pain, called angina, and heart attacks. People are more likely to die from heart disease than cancer, stroke, lung diseases or accidents. Each year, almost 500,000 Americans die from CHD.
The lifetime risk estimate for CHD is an average value for the general population, but individuals may have higher or lower absolute lifetime risks depending on whether or not they smoke, have high blood pressure, high blood cholesterol, or diabetes, are sedentary or overweight.
"When it comes to health, average isn't always good," says Daniel Levy, M.D., the study's principal investigator. "The fact that the average 50-year-old woman is three times more likely to get CHD than breast cancer during her lifetime has important implications for public health." Dr. Levy says the study will help policy makers assess the risks and burdens for various diseases and help the public understand why heart disease prevention is so important.
The study also has implications for older Americans, and the physicians caring for them, who may have believed that persons who survive to an older age without CHD are no longer susceptible to developing it. Since even at age 70 the average person remains at high risk, greater emphasis should be placed on control of risk factors in older men and women, says Dr. Levy.
The Framingham Heart Study began 50 years ago in Framingham, Massachusetts. To study more recent trends in the risk of coronary disease, new cases of heart disease occurring between 1970 and 1996 were identified by NHLBI researchers working in collaboration with scientists from Boston University. The 7,733 volunteers, aged 40-94, provided a well-described population with long-term follow-up and carefully documented CHD events and causes of death. The researchers calculated lifetime risks for CHD for ages 40, 50, 60, and 70. In all categories, men had a higher lifetime risk than women.
Other estimates of CHD lifetime risk have been limited by reliance on death certificate data or short-term follow up, according to Dr. Levy.
Donald M. Lloyd-Jones, M.D. and Daniel Levy, M.D. are available to comment. To schedule an interview contact the NHLBI Communications Office at (301) 496-4236.