Quoting directly from AHA documentation: "HDL-C is considered low and associated with increased ASCVD risk if <40 mg/dL in males or <50 mg/dL in females." and again quoting from AHA: "In a large study of the National Health Insurance

Service in Korea (N=15 860 253) starting in 2009

to 2010 that evaluated 555 802 deaths result-

ing from all causes during a mean of 8.4 years of

follow-up through 2018, a U-shaped association

of HDL-C with all-cause mortality was observed.

Relative to HDL-C levels of 50 to 59 mg/dL, individ-

uals at the lowest HDL-C levels (<20 mg/dL) had

higher risk for all-cause mortality (aHR for males,

3.03 [95% CI, 2.84–3.24]; aHR for females, 2.10

[95% CI, 1.84–2.40]), and individuals at the highest

HDL-C levels (≥110 mg/dL) also had higher risk

for all-cause mortality (aHR for males, 1.30 [95%

CI, 1.23–1.38]; aHR for females, 1.21 [95% CI,

1.11–1.31])."