What Actually Causes Heart Disease? (The 5 Studies That Proved It)

I'm Dr. Jeremy London, a board-certified cardiovascular surgeon in practice for over 25 years. In this episode I break down five landmark cardiovascular studies, the foundational research that did the heavy lifting to shape how we treat heart disease today.

But this isn't just a history lesson. I walk through each study the same way a physician does: how the study was designed, what it got right, what it got wrong, and whether it held up over time. That framework is the real takeaway, because in an age of overwhelming health information, knowing how to evaluate a study is more valuable than memorizing any single result.

We go from Framingham in 1948, which invented the very idea of a "risk factor," all the way to SPRINT in 2015, which changed the blood pressure number we all aim for. Along the way you'll see exactly how these studies stack on top of each other to answer the next question: Do risk factors exist? Which ones matter most? Is one of them actually causal? And how hard should we push when we treat them?

Medical science isn't stone tablets. It's guidance, and it should be pressure-tested constantly. Strong beliefs, loosely held.

Thank you to our sponsors:

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CHAPTERS

0:00 – What this episode covers & why foundational studies matter

2:10 – Study #1: The Framingham Heart Study (1948)

4:15 – What Framingham got right: risk factors compound

5:05 – Where Framingham fell short, and how it holds up today

6:05 – Study #2: The 2013 smoking study (200,000 smokers)

7:15 – Quitting before 40 drops your risk by nearly 90%

7:35 – The study's flaws, and why the numbers still hold

9:20 – Sponsor: LMNT

10:45 – Study #3: INTERHEART, 52 countries, 9 risk factors

11:20 – Ranking the risk factors: cholesterol, smoking, stress

12:15 – The weakness of a retrospective study

13:00 – Study #4: Mendelian randomization: is cholesterol causal?

13:40 – Why the "ideal" cholesterol study can't ethically be run

14:20 – Nature's controls: the genetic lottery on both ends

15:55 – Lower is better, earlier is better (the sun exposure analogy)

17:30 – Where it holds up today: apolipoprotein B

18:15 – Sponsor: Function Health

19:40 – Study #5: The SPRINT trial (2015), how low should BP go?

20:35 – Why they stopped the trial early

21:20 – The catch: how blood pressure was actually measured

22:20 – Why 120 became the standard

23:10 – Putting all five together: the decision-making chain

24:20 – How to evaluate any medical study yourself

25:45 – "Strong beliefs, loosely held"

26:15 – Closing thoughts

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