A 30-year study of thousands of healthy women found that having "very high" levels of a genetically determined cholesterol-like particle significantly elevates the long-term risk of heart attack, stroke and death from cardiovascular disease. According to the study of 28,000 women published Wednesday in the Journal of the American Medical Association, the particle called lipoprotein(a) or Lp(a) is different from the cholesterol typically talked about.

The LP(a) level is set by genes and is not significantly affected by diet or exercise. This means a person can lead a very healthy lifestyle and still have dangerously high levels without knowing it.

"Lipoprotein(a) is a particularly dangerous form of cholesterol that can lead to cardiovascular disease by promoting atherosclerosis, which is plaque in the arteries of the heart and other blood vessels, such as the brain," said Dr. Nisha Parikh, system director for the Women's Heart Program at Northwell Health.

Parikh, who did not author the study, said women can go for testing after speaking with their physicians about their concerns. In addition, a doctor can choose to be more aggressive in modifying the risk by putting patients on cholesterol lowering medicine or discussing more intense lifestyle changes.