Lowering Bad Cholesterol Linked to Reduced Alzheimer's Risk

Recent research from the University of Texas Health Science Center at San Antonio has established significant correlations between blood lipid levels and the risk of developing Alzheimer's disease, the most prevalent form of dementia worldwide. The study suggests that monitoring lipid profiles in the blood could enhance our understanding and potential prevention strategies for this debilitating condition.

In a detailed analysis involving over 800 older adults from the long-standing Framingham Heart Study, researchers identified that elevated levels of small dense cholesterol particles, recognized for their role in increasing the risk of atherosclerosis and coronary heart disease, correlated with a heightened risk of Alzheimer's disease. Conversely, the study found that higher levels of a marker associated with small fat-carrying particles, which transport dietary fats from the digestive system to various tissues in the body, were linked to a lower risk of developing dementia.

Interestingly, the researchers also noted that individuals with minimal amounts of high-density lipoprotein (HDL), often referred to as "good cholesterol"--which is typically seen as protective against heart disease--exhibited a reduced risk of Alzheimer's compared to those with higher HDL levels.

Dr. Sokratis Charisis, a researcher at the Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases at UT Health San Antonio, emphasized the intricate relationship between blood lipids and both cardiovascular and brain health. The findings imply that certain lipids may play divergent roles in the biological processes linked to heart disease and dementia.

The study, published on May 30 in the journal Neurology, titled "Association of Blood Lipoprotein Levels With Incident Alzheimer's Disease in Community-Dwelling Individuals: The Framingham Heart Study," involved contributions from various institutions, including Boston University School of Public Health and the University of Texas Rio Grande Valley.

Dementia remains a significant cause of illness and mortality among the aging populace, with approximately 57.4 million individuals living with the condition globally in 2019--a figure projected to rise to 152.8 million by 2050. Notably, there has been a general decline in the incidence of Alzheimer's and other dementias in the U.S. and other high-income nations, attributed partly to improved management of cardiovascular risk factors.

The Framingham Heart Study, an ongoing community-based cohort initiative initiated in 1948, has continuously tracked health metrics of participants, including lipid levels and cognitive health. The latest analysis focused on participants aged 60 and older, who were free of dementia during the examination period spanning from 1985 to 1988, and had available data on cognitive follow-up and lipoprotein markers.

Researchers measured levels of HDL cholesterol, low-density lipoprotein cholesterol (LDL), and small dense LDL, among other types of lipoproteins linked to heart disease, utilizing blood samples collected during the mid to late 1980s. Participants were monitored for new cases of Alzheimer's disease until 2020, with 128 out of 822 participants developing the condition.

The data indicated that a one standard deviation increase in small dense LDL concentration was associated with a 21% greater likelihood of developing Alzheimer's. In contrast, a similar increase in ApoB48 concentration, a lipoprotein responsible for transporting dietary fat, correlated with a 22% reduction in Alzheimer's risk.

Additionally, participants with lower HDL cholesterol levels were found to be 44% less likely to develop Alzheimer's compared to those with higher levels. Those with small dense LDL concentrations below the median were also 38% less likely to develop the disease compared to individuals with higher levels.

These findings highlight the potential for specific blood lipoprotein markers to play a significant role in assessing Alzheimer's risk and underscore the importance of lipid management strategies in the prevention of dementia.