A number of studies have tied low blood levels of HDL to an increased risk of ischaemic heart disease. However, whether HDL cholesterol is a primary factor in the development of heart disease is unclear, in part because of other factors related to low HDL cholesterol levels, such as harmful triglycerides, which may contribute independently to increases in heart and vascular events.
Doctors from Copenhagen University Hospital, Denmark studied a group of patients with mutations in the ABCA1 gene causing reductions in HDL cholesterol levels but not increases in triglyceride levels.
The principal finding is that mutations in ABCA1 associated with "substantial, lifelong lowering of plasma levels of HDL cholesterol, but not with corresponding higher levels of plasma triglycerides or atherogenic remnant lipoproteins, did not predict an increased risk of (heart disease)."
