Most of us who’ve visited a doctor in the last couple of decades, or who’ve watched drug commercials wrapped around the evening news, are familiar with the myriad threats to our hearts. Cigarette smoking is one. Obesity and high blood pressure are others. Never mind bad cholesterol, or the positive effects associated with “good” cholesterol.

Much of this basic health knowledge, so widely shared in the U.S. and developed world, draws upon a study launched here in Massachusetts a few years after World War II. The Framingham Heart Study, rolling along for 71 years now, is a monument to the efforts of researchers to identify and contain the risk of heart disease.

Now following a third generation of subjects, the study turned another corner Tuesday when Boston University, which has overseen it since 1971, announced $38 million in funding to monitor the blood pressure, platelets, liver fat and arterial health of older participants. The research funded by the National Heart, Lung and Blood Institute ensures the study continues for at least six more years.

A focus on the population over 65 comes at an important time, said Dr. Vasan Ramachandran, a BU professor and director of the study. “With the rapidly increasing number of Americans over the age of 65 years, comprehensive studies of older individuals are invaluable,” he tells BU Today. “The opportunity to perform comprehensive analysis of … abnormalities in older individuals, using state-of-the-art scientific technology, is unparalleled.”

Indeed, the Framingham Heart Study itself is unparalleled. Its origins lie in a law signed June 16, 1948 by President Harry Truman, setting aside a half million dollars for a 20-year heart study. According to a history of the research prepared for the National Institutes of Health, the hypertension and stroke that afflicted President Franklin D. Roosevelt, leading to his death on April 12, 1945, gave momentum to the investigation.

“Like countless other Americans, he had succumbed to the national epidemic of cardiovascular disease,” wrote the medical historians, who noted that heart disease then accounted for one in two deaths in the U.S.

According to the U.S. Centers for Disease Control, it remains the country’s leading cause of death even today.

That we know as much as we do about it today is credit to the Framingham researchers, who signed up 5,209 men and women, ages 30 to 62, as their subjects. They chose Framingham for several reasons, including the common European ancestry of much of its population, and the town’s proximity to many of the doctors involved in the project. Ironically, according to the history of the project, an early annual budget of $94,350 included money for ashtrays for the staff.

The study’s subjects submitted to routine tests and physicals, and after 23 years their pool grew to include 5,124 children and spouses. A third generation — grandchildren of the first subjects — signed on in 2002.

The study has also twice expanded, in 1994 and again in 2003, to include a more diverse panel of subjects.

The work of researchers monitoring the health of this community — in many cases well after their subjects packed up and left Framingham — has made an indelible mark on what we understand about health. A dozen years after the study started, researchers connected cigarette smoking and heart disease. A decade after that, they tied high blood pressure to the risk of stroke. Scientific findings drawn from countless surveys and checkups have piled up through the years. (You can find them listed online at www.framinghamheartstudy.org.)

The study, as an early director noted, was a key effort toward bending the perception of medicine in the mid-20th century from being an exercise in treating illness to one of avoiding it. Along the way, it also disproved some widely held beliefs, such as the notion that systolic blood pressure wasn’t very important. Now, we know it to be a key warning sign of heart disease.

Given such a rich history, one can only wonder about the future discoveries that will come as researchers and their subjects aim to contain and prevent the dangerous diseases of the heart. And it is a comfort to know that the Framingham Heart Study beats on.