The NHLBI has pioneered research that helped shape the understanding of risk factors for cardiovascular disease in middle-aged Americans. The goal of the Cardiovascular Health Study (CHS) is to identify risk factors for cardiovascular disease related to the onset of coronary heart disease and stroke in adults aged 65 or older. The CHS also serves as a platform to investigate a variety of other research topics that impact older adults, such as pulmonary disorders, diabetes, kidney disease, vascular dementia, and frailty.
One of the most frequently cited papers to emerge from the CHS included the results of a study that explored the contribution of cardiovascular disease that is present without specific symptoms. Researchers found that as we age, a large amount of plaque buildup and thickening occurs in the carotid arteries, and these changes may not cause symptoms. The presence of this plaque, known as atherosclerosis, predicts a higher risk of a stroke or heart attack. This was a landmark finding, demonstrating the importance of identifying the earliest stages of a cardiovascular disease process.
Many CHS papers have evaluated measures of risk factors in early cardiovascular disease for later onset of stroke, heart failure, heart attack, and atrial fibrillation. Early, or subclinical, cardiovascular disease does not produce signs or symptoms that are detectable by physical exam or laboratory test. The CHS study characterized the importance of subclinical cardiovascular disease as a risk factor for clinical (disease with overt signs and symptoms) cardiovascular disease and mortality, as well as for reduced physical and cognitive function.
The CHS also was one of the first studies to characterize a type of heart failure not associated with reduced heart pumping. The risk of heart failure increases with age. In older adults, CHS found that the heart appears to pump well on an echocardiogram, but with age, the heart becomes stiff, which causes a different kind of heart failure than is seen, for instance, after a heart attack. The CHS also has documented the incidence of, risk factors for, and health consequences of atrial fibrillation.
In addition, the CHS helped identify other predictors of future health problems in older adults. CHS researchers identified the syndrome of frailty in participants who experienced weight loss, fatigue, slow walking, low physical activity, and muscle weakness. Those who showed signs of frailty were more likely to be hospitalized or have a fall than participants who did not experience these symptoms. This finding has led to new research questions and has affected clinical care.
The NHLBI continues to leverage CHS data and specimens to spur new scientific discovery. The NHLBI encourages researchers to utilize the valuable resources that have been collected over 25 years. Learn more about utilizing CHS resources through the study website; through NHLBI’s Biologic Specimen and Data Repositories Information Coordinating Center (BioLINCC); and through the NIH Database of Genotypes and Phenotypes (dbGaP).
The study recruited 5,888 men and women aged 65 or older in four U.S. communities—Sacramento, CA; Hagerstown, MD; Winston-Salem, NC; and Pittsburgh, PA—conducting annual clinical exams between 1989 and 1999. CHS research was conducted with an emphasis on subclinical measures, or measures of disease without signs and symptoms that are detectable by physical examination or laboratory test. Extensive initial physical and laboratory evaluations were performed to identify the presence and severity of cardiovascular risk factors, such as high blood pressure, high cholesterol, and pre-diabetes; subclinical disease, such as carotid artery atherosclerosis, left ventricular enlargement, and transient ischemia; and cardiovascular disease that has obvious signs and symptoms. These exams permitted evaluation of cardiovascular risk factors in older adults, particularly in groups previously under-represented in studies, such as women, African-Americans, and adults aged 65 or older.
Participants were seen annually in the clinic, and contacted by phone at six-month intervals to collect information about hospitalizations and potential cardiovascular events. Major exam components were repeated during annual follow-up examinations through 1999 and again in 2005. Since 1999, participants have been contacted every six months by phone, primarily to assess health status for cardiovascular events and physical and cognitive functions.
Visit the CHS website for more information on the study field sites and the coordinating and collaborating centers.
In 1948, President Truman signed legislation that created what is now the NHLBI to address America's emerging cardiovascular disease epidemic. In the decades since its founding, the NHLBI has funded research that has led to a dramatic 40 percent reduction in annual deaths from both heart disease and stroke and is now averting over 1 million deaths annually from coronary heart disease – a phenomenal return on the nation’s public investment in medical research.