Almost everyone who had their first heart attack, stroke, or heart failure already had a known risk like high blood pressure, high cholesterol, high blood sugar, or a history of smoking.

What we've found so far is that nearly all people who experience a first heart attack, stroke, or heart failure already have at least one well-known risk factor such as high blood pressure, high cholesterol, high blood sugar, or a history of smoking [1]. Our analysis of the available evidence shows this pattern is consistently reported across the studies we’ve reviewed. The evidence we’ve examined indicates that these major risk factors are almost always present before a first cardiovascular event [1]. That means, in the cases studied, very few people had a heart attack or stroke without already having one of these conditions on record. High blood pressure, high cholesterol, and high blood sugar are all linked to long-term damage to blood vessels, and smoking adds further strain on the heart and circulation. When these factors are present, they may silently increase risk over time, even if a person feels fine. We don’t yet know how many people might have a cardiovascular event without any known risk factors, because the evidence we’ve reviewed focuses on those who do have them—and in those cases, risk factors are nearly universal [1]. Still, our current analysis is based on a limited number of assertions—only one distinct claim supported by 20 studies—so we can’t say how this applies across all populations or whether other patterns might emerge with more data. What this means for you: Most people who have a first heart-related emergency already know about at least one major health risk. This suggests that paying attention to blood pressure, cholesterol, blood sugar, and smoking could make a big difference. Catching and managing these issues early—before symptoms appear—might help lower your risk, even if you feel healthy now.