High cholesterol may increase your risk for this dangerous condition

By Alistair Gardiner
Published June 16, 2021

Key Takeaways

Concerns about high cholesterol levels typically stem from efforts to prevent heart disease and stroke later in life. But recent studies indicate that there’s another reason why we should all be paying attention to our cholesterol, even from a young age: Obesity and high cholesterol in youth may lead to earlier and more significant cognitive decline later in life and may significantly increase risks of conditions like dementia.

Low levels of cholesterol, on the other hand, may significantly slow cognitive decline. 

Here’s what the most recent research says about the link between cholesterol and brain health.

New evidence

Preventive treatments are the best way to tackle cognitive decline, because subclinical cognitive deficiencies (including problems with memory, learning, or decision-making) tend to precede the condition by years or even decades. While some cognitive decline is a natural part of aging, certain behaviors and health conditions can increase a person’s risk, including hypertension, type 2 diabetes, smoking, physical inactivity, and poor diet, among others.

While past research has found that cardiovascular risk factors (CVRFs) are associated with increased risks of cognitive decline, almost all of it has focused on CVRFs in later life. But authors of a new study published in Circulation have taken a new approach, examining the association between CVRFs in youth and cognitive decline mid-to-late life. 

They examined data from a cohort of 2,026 participants aged 34 to 49 years who were followed during the previous 31 years. During that period, all participants were regularly checked for CVRFs like blood pressure, serum lipids, and BMI. They then took a computerized cognitive test that measured their abilities in areas like episodic memory, visual processing, and sustained attention.

Participants with higher than average blood pressure and total cholesterol levels performed worse in episodic and associated learning tasks. What’s more, those who had lived with obesity since childhood exhibited worse visual processing and sustained attention skills.

The authors concluded that CVRFs experienced in childhood—including total cholesterol—are inversely associated with midlife cognitive performance. They also noted that the higher the number of CVRFs, the worse the cognitive performance. 

The findings suggest that early prevention strategies for children with CVRFs should be a priority because they could stop or slow the development of cognitive decline and dementia later in life. 

Lowering LDL-C cholesterol can reduce neurodegenerative risks

The above study is one of many aiming to clarify the link between cholesterol and cognitive function. Another study, published in Science Bulletin, focused on levels of low-density lipoprotein cholesterol (LDL-C) and associations with cognitive decline. 

While previous evidence suggests that lower LDL-C levels result in a lower risk of future cardiovascular events, the relationship between LDL-C and cognitive decline has historically not been the focus of many studies. 

As such, researchers gathered data from a cohort of 7,129 participants with an average age of 69 years. After comparing their LDL-C levels and cognitive abilities, they found that those with LDL-C levels of <55 mg/dL had significantly slower 2-year decline rates in cognitive function, working memory, and episodic memory vs those with LDL-C levels of 70.0–99.9 mg/dL. They also found significantly slower rates of cognitive decline in those with LDL-C levels of 55.0–69.9 mg/dL vs participants in the highest percentile.

Given how few therapeutics for cognitive impairment are currently available, researchers concluded that working on lowering LDL-C at the earliest available time should be a focus for interventions to prevent or delay dementia. 

A complicated relationship

Despite these recent advancements, the association between cholesterol and cognition is still worthy of additional attention. That’s according to a study published in Frontiers in Aging Neuroscience, in which researchers examined the relationship between plasma total cholesterol level, gray matter volume, and cognitive performance in a group of elderly individuals. 

The 117 participants had an average age of 61.5 years and no history of dementia, and they were studied alongside 50 demographically matched controls. Interestingly, the authors not only found that high total cholesterol levels were associated with poorer cognitive performance and reduced amounts of grey matter, they also found that those with very low total cholesterol exhibited poorer cognitive abilities and had reduced amounts of grey matter.

The authors posited that while very high total cholesterol may adversely impact brain health through mechanisms relating to CVRFs, very low total cholesterol may be detrimental to cognitive functions due its impact on brain microstructure and function. As noted in the aforementioned Science Bulletin study, cholesterol is the main constituent of the brain myelin encircling neurons, and negative neurocognitive outcomes have been reported with various lipid-lowering drugs. 

While further research is necessary to fully understand this complex relationship, it may well be that maintaining a moderate level of total cholesterol and controlling levels of LDC-C is the key to protecting your future brain health. 

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