What long-running cohort studies taught us
In 1948, researchers started checking the health of thousands of people in one Massachusetts town. They’re still going, and they gave us the phrase “risk factor.”
The short version
- The Framingham Heart Study began in 1948 with 5,209 adults in Framingham, Massachusetts.
- It helped show that high blood pressure, high cholesterol, and smoking lead to heart disease.
- Its main limit: it shows links, and early on most participants were white and middle-class.
Why the study started
By the 1940s, heart disease was the leading cause of death in the United States, and doctors didn’t know why. High blood pressure was often seen as a normal part of aging. The US government funded a study to follow healthy adults over time and see who got sick.
What it found
Framingham enrolled 5,209 men and women aged 30 to 62 and examined them every two years. Over the following decades it linked high blood pressure, high cholesterol, smoking, diabetes, obesity, and inactivity to heart disease. The term “risk factor” came out of this work in the early 1960s. The study later enrolled participants’ children and grandchildren.
What we know now about its limits
Cohort studies show links, not proof. Framingham’s findings on blood pressure and cholesterol were later confirmed by randomized trials of treatments. Its early participants were mostly white and from one town, so newer cohorts were needed to check whether the findings held for other groups.
Why it matters for this site
Several of our articles come from big cohort studies, like the 56,000-person Danish greens study. Framingham is why those are worth taking seriously, and why we still say “linked to” for them.
Sources
Educational information, not medical advice. Read our medical disclaimer.