HDL Cholesterol and Non-Cardiovascular Disease: A Narrative Review

Area of Science:

• Cardiovascular Research
• Metabolic Health
• Aging and Disease

Background:

• High density lipoprotein (HDL) cholesterol is traditionally known as "good cholesterol".
• Decades of research focused on HDL's role in atherosclerosis and cardiovascular disease.
• Recent randomized trials targeting increased HDL cholesterol have yielded negative results.

Purpose of the Study:

• To review emerging associations between HDL cholesterol and non-cardiovascular diseases.
• To explore the implications of these findings for human health and disease.
• To synthesize evidence from observational studies, genetics, and proposed mechanisms.

Main Methods:

• Narrative review of existing literature.
• Analysis of observational studies linking HDL cholesterol to various non-cardiovascular conditions.
• Examination of human genetic data related to HDL cholesterol.
• Discussion of potential biological mechanisms.

Main Results:

• High HDL cholesterol levels are not consistently associated with positive health outcomes in non-cardiovascular diseases.
• Observed associations include age-related macular degeneration, type II diabetes, dementia, infection, and mortality.
• These findings challenge the traditional view of HDL cholesterol's universal protective role.

Conclusions:

• The role of HDL cholesterol in overall human health requires re-evaluation beyond cardiovascular disease.
• High HDL cholesterol may not always confer a health benefit and could be linked to adverse outcomes in certain conditions.
• Further research into HDL's complex functions and interactions is warranted.