https://www.nature.com/articles/s41598-021-01738-w
"For decades, the high level of low-density lipoprotein cholesterol (LDL-C) has been considered as the main cause of the development and death of atherosclerotic cardiovascular diseases1. A large number of studies have strongly shown that the reduction of plasma LDL-C concentration by lipid-lowering drugs is related to the greater reduction of the development and mortality of cardiovascular diseases2,3,4,5,6,7,8,9.
However, many studies have found the opposite result to previous studies on cardiovascular diseases, and LDL-C level is negatively correlated with all-cause mortality of patients10,11.
Conclusion:
In a nationally representative sample of US, low LDL-C level was found to be associated with higher risk of all-cause mortality after adjusting for confounding factors, such as age, sex, race, marital status, education level, smoking status, BMI, hypertension, diabetes, cardiovascular disease, cancer. There is a U-shaped relationship between LDL-C level and all-cause mortality. Compared with the middle LDL-C level, the lower LDL-C level and the higher LDL-C level, may have higher all-cause mortality. Further studies are warranted to determine the causal relationship between LDL-C level and all-cause mortality."