By GINA KOLATA New York Times
Has anyone investigated about the consequences of low cholesterol levels? Cholesterol is the precursor of adrenal hormones, a constituent of membrane caveolae important for signal transduction, and it is the precursor of biliary salts.
It depends on what you mean by “low.” Clinical trials of statins showed that reducing LDL levels protects against cardiovascular disease and found that the lower the LDL levels, the better. That is why guidelines call for people at high risk to aim for LDL levels of 70. But statins are not as powerful as the new drugs that inhibit PCSK9. The clinical trials getting started now should show if there are adverse effects to driving LDL levels very low, far below 70.
Those with low cholesterol levels may die less from heart attacks, but does low cholesterol raise death rates from other diseases, such as cancer? Reports several years ago said that the elderly, put on statins, had a one-third chance of being diagnosed with cancer the next year.
There was a concern years ago that low cholesterol levels increased cancer risk but that has not been borne out. However, it is not clear whether there is a threshold for cholesterol lowering. It might be that beyond a certain point there are no further benefits or even that there are more health problems. That is what the current very large studies of the new PCSK9 inhibitors are hoping to find out.
I realize that statins decrease cholesterol. But is there any good evidence that lower cholesterol leads to less heart disease in healthy patients?
Yes. Large clinical trials of statins asked exactly that question and found that those who lowered their cholesterol levels had fewer heart attacks and less angina, and a lower cardiovascular death rate.