Almost everyone who had their first heart attack already had at least one common risk factor like high blood pressure, high cholesterol, high blood sugar, or a history of smoking—this was true for nearly all people in big studies from Korea and the U.S.

What we've found so far is that nearly all people who experience a first heart attack already have at least one major risk factor such as high blood pressure, high cholesterol, high blood sugar, or a history of smoking [1]. Our analysis of the available research shows this pattern held true across large studies in both the U.S. and Korea [1]. The evidence we’ve reviewed leans heavily toward the idea that these common risk factors are present before a heart attack occurs. In fact, out of the data we analyzed, 49.0 supporting assertions indicate that very few first heart attacks happen in people without one of these known risks [1]. We found no studies that contradict this observation. It’s important to note that our current analysis is based on a limited number of assertions—just one distinct claim supported by multiple lines of evidence. While the direction of the evidence is clear, we remain cautious about overgeneralizing. We don’t yet know how often rare cases without traditional risk factors might occur, or what other factors could be at play in those instances. We also can’t say from this evidence alone whether having these risk factors directly leads to heart attacks—only that they are almost always present beforehand. Our analysis does not explain why this association exists, only that it appears strongly in the data we’ve reviewed so far. Practical takeaway: Most people who have a first heart attack already have known health risks like high blood pressure, high cholesterol, or a history of smoking. Keeping an eye on these factors—and working to improve them—might help lower your risk, based on what we’ve seen so far.