Heart attacks and strokes rarely occur without warning.

According to health data from more than 9 million adults in South Korea and the US, nearly everyone who develops heart disease and suffers a major cardiovascular event has one of four major risk factors in the lead-up.

These factors include high blood pressure, high cholesterol, high blood sugar levels, and tobacco smoking (past or current).

Combined as a group, they preceded 99 percent of all cardiovascular events during the long-term study, which was published in 2025.

Even in women under 60 – the demographic with the lowest risk of cardiovascular events – more than 95 percent of heart attacks or strokes were linked to one of these existing risk factors.