Don't Know. High hdl-c (HDL cholesterol) levels are associated with lower risk of heart disease for populations of patients. For individuals, however we cannot say this. In fact, high HDL can be cause by many things, one of which is increased cholesterol absorption, and may not protect against elevated levels of LDL cholesterol or apo b or LDL particle levels. Hdl can be high but "dysfunctional".
No. Hdl (high-density lipoprotein) isn't really a cholesterol measurement to begin with....It's a carrier protein that assists in transporting away and decreasing risk of cholesterol deposits in blood vessel walls. There are no studies indicating a "dangerously" high level, but, of course, a high HDL is a great heart protective measurement.