But new research suggests that there could be too much of a "good" thing. Very high blood levels of HDL cholesterol may actually be bad for you. The research linked it to a higher risk for heart attack, and even death, among patients who already had heart problems or who faced a higher risk of developing heart disease.
The findings are based on a roughly four-year tracking of cholesterol levels and heart disease among nearly 6,000 men and women.
another article: https://www.sciencedaily.com/releases/2018/08/180825081724.htm
Participants with HDL cholesterol levels greater than 60 mg/dl (1.5 mmol/L) had a nearly 50% increased risk of dying from a cardiovascular cause or having a heart attack compared to those with HDL cholesterol levels 41-60 mg/dl (1.1-1.5 mmol/L).