The Framingham Heart Study has led not only to a better understanding of cardiovascular disease and its risk factors, but has provided valuable insight into the risk factors for stroke and dementia, a renowned neurologist said Tuesday.
Philip A. Wolf, MD, FAHA, made the comments during his Distinguished Scientist Lecture. The study, which launched in 1948, has followed multiple generations of residents from Framingham, Massachusetts.
“Mortality from stroke had been declining steadily at about 1 percent a year until the late 1970s, when (the decline) accelerated to about 7 percent per year, perhaps as a reflection of the advances in detection and attention to high blood pressure and other preventive measures,” said Wolf, the first neurologist to join the Framingham research team, in 1967, and the study’s principal investigator in 1989-2014.
Wolf credits the many studies and volumes of data generated from the Framingham population for much of what we know today about the risk factors for stroke, noting that the Framingham risk profile has been used for more than 25 years to estimate the probability of stroke.
Wolf was co-author of a landmark paper published in JAMA in 1970 that was among the first to clearly establish blood pressure as a risk factor for stroke.
“We showed that, as blood pressure increases, the cumulative risk of stroke increases,” he said. “That was important because it made it clear that prevention and the mediation of risk factors was the goal. Today, we believe we have the tools to prevent up to 75 percent of strokes.”
Wolf cited statistics from the Centers for Disease Control and Prevention, which estimates the number of initial strokes per year in the United States at 610,000 — a number that could reach 1 million by 2050, according to an estimate from the National Institutes of Health. The risk of stroke or dementia is one in two for women and one in three for men, said Wolf, highlighting the need for more focused efforts on prevention and patient education.
Research has shown that many of the risk factors for stroke —hypertension, obesity, smoking, diabetes and physical inactivity — are also risk factors for cognitive decline and dementia.
“In a 1993 study, for example, we found that cognitive functioning was strikingly related to both age and level of systolic blood pressure,” Wolf said. “While early on in Framingham we focused a lot of attention on severe dementia, in more recent years that focus has shifted to detecting mild cognitive impairment and identifying people earlier in life who may be at risk and who may benefit from preventive efforts.”
In 1999, The Washington Post called the Framingham Heart Study one of the most important epidemiological studies and one of the top five medical accomplishments of the 20th century.