In the 1950s, total cholesterol was the only measurable cholesterol metric and was loosely correlated with cardiovascular disease outcomes only at the extreme ends of the spectrum.

“in the 1950s when it became clear that cholesterol was playing a role in cardiovascular disease the first observation was people with very very very high total cholesterol because at the time that was all that could be measured was total cholesterol by the way what that meant was the total amount of cholesterol in all of your lipoproteins in your hdls in your ldls and in your vldls those three lipoproteins constitute the amount of total cholesterol you have in the lipoproteins we can come back to this idea because it's important that represents about 10% of the total cholesterol in your body the total cholesterol concentration was Loosely correlated with cardiovascular outcomes but only at extremes meaning if you you took people whose total cholesterol was in the top 5% and compared them to people whose total cholesterol was in the bottom 5% there was a clear association with cardiovascular disease”