Sometimes new research makes us reconsider what we know. One example this year was cholesterol, which has long been divided into black-and-white simplicity — good and bad, HDL and LDL. Because people with higher HDL tend to have fewer heart attacks (and those with high LDL have more of them), it has been a fair distinction.
Or has it? An international team looked at medical data from thousands of people with and without a history of heart attacks, a collection that included some who had genetic variants resulting in higher-than-average HDL.
Surprisingly, the researchers found that having naturally higher HDL imparted no added protection against heart attacks (SN: 6/16/12, p. 14).
The very activities that can increase HDL — exercising, losing weight and stopping smoking — also do their part to protect against heart attacks, which has made it hard to discern how much protection HDL actually provides on its own. The new findings, reported in August, question whether HDL delivers much benefit at all and raise the possibility that having high HDL might simply be a sign of something else that is going right in the body.