Can high cholesterol increase your chances of developing dementia? High cholesterol was always viewed as a heart-health problem. Recently, it has also been increasingly associated with a potential long-term concern for our brain health.
In an interview with HT Lifestyle, Dr Sachin explained that the strongest evidence for a correlation between high cholesterol and dementia currently comes from studies that have examined cholesterol levels in midlife and followed people over many years. To understand this correlation, first, we need to understand dementia and cholesterol. In an interview with HT Lifestyle, Dr Arun Shah, director of neurosciences, Sir HN Reliance Foundation Hospital. Dr Arun explained that dementia is not a single disease but an umbrella term for a loss of memory, language, problem-solving, and other cognitive abilities that is severe enough to interfere with daily life. “A person’s cognitive ability includes communicating with other people, executive function, performing tasks, social awareness, memory, judgment, and thinking ability. Dementia is not part of normal ageing. There are many risk factors which can lead to vascular dementia – hypertension, diabetes, obesity, sleep apnea, smoking, and multiple strokes,” he added. On the other hand, cholesterol is a waxy, fat-like substance that your body needs to function properly. The liver is the main producer of cholesterol in the body, Dr Arun added. “As it is a fat, it does not dissolve in the blood and is transported in the form of lipoproteins like LDL and HDL. Low-density lipoprotein (LDL) is known as the ‘bad’ cholesterol, and high-density lipoprotein (HDL) is called the ‘good’ cholesterol,” he explained. Cholesterol is not always bad and plays important roles in the body, Dr Arun stressed, adding, “It provides stability and flexibility to the outer layer of every single cell in our body. It serves as the primary building block for essential hormones, including estrogen, testosterone, and cortisol. The liver uses cholesterol to make bile acids, which are crucial for helping our intestines digest fats and absorb fat-soluble vitamins (A, D, E, and K). Regarding the link between dementia and cholesterol, Dr Sachin stressed that there is a plausible biological explanation for this association. He states that “persistently elevated LDL cholesterol contributes to atherosclerosis and vascular injury. “Over decades, this can affect the blood vessels supplying the brain, increase the risk of stroke and small-vessel disease, and potentially contribute to cognitive decline. Vascular injury can also interact with the pathological processes underlying Alzheimer’s disease,” Dr Sachin warned. More importantly, he explained that the relationship between cholesterol and dementia is not simply about one high cholesterol reading.
He cited a landmark 2023 research paper involving 1.2 million participants, published in the Alzheimer’s & Dementia Journal. The meta-analysis found that midlife hypercholesterolaemia was associated with a 14% higher incidence of all-cause dementia.
However, according to Dr Sachin Adukia, senior consultant, MBBS, MD (general medicine), DNB (neurology), it would be an oversimplification to say that having high cholesterol in your 30s could directly cause dementia . “The same analysis found that every 1 mmol/L (about 39 mg/dL) increase in LDL cholesterol was associated with an 8% increase in dementia incidence,” he added. “The duration of exposure, LDL levels, blood pressure, diabetes, smoking, obesity, physical inactivity and other vascular risk factors all matter,” he added, citing the research from the Kaiser Permanente cohort, which found that people with high cholesterol at 40 to 45 years had a higher risk of developing Alzheimer’s disease decades later.
For people in their 30s, Dr Sachin outlined that the message should be one of ‘prevention rather than fear’. It is an opportunity to identify lifetime cardiovascular risk early, particularly when LDL cholesterol is markedly elevated, or there is a family history, suggesting familial hypercholesterolaemia,” he explained. Because dementia seems far away, “High cholesterol at this age should not be ignored simply.
At the same time, he added that a 14% relative increase in risk does not mean that ‘14 out of every 100 people with high cholesterol will develop dementia. Therefore, “controlling cholesterol, blood pressure, diabetes, smoking, weight and physical inactivity from early adulthood is likely to be far more meaningful than waiting until cognitive symptoms appear. These are population-level associations, and they do not establish that cholesterol alone is the cause, he underlined. Lastly, Dr Sachin stated that brain health is ultimately vascular health as well. Meanwhile, Dr Arun cautioned that high cholesterol levels are detrimental to overall health, as they lead to plaque formation, vascular damage, and endothelial damage in blood vessels. “All of these lead to brain damage in the long-term, which ultimately leads to dementia. This is being seen in the young population, where overeating and eating junk food lead to high cholesterol accumulation, and repetitive habits lead to a high cumulative burden on the brain. Hence, it is advisable to have a disciplined lifestyle from a young age to prevent diseases of old age like dementia, strokes, and hypertension,” he cautioned. Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.
