Lower Bad Cholesterol to Reduce Risk of Alzheimer’s and Dementia, Experts Say

New Delhi: Lowering bad cholesterol levels may play a significant role not only in supporting heart health but also in reducing the risk of cognitive disorders such as Alzheimer’s disease and dementia, a recent study has found.

Published in the Journal of Neurology, Neurosurgery and Psychiatry, the research highlights that maintaining low levels of low-density lipoprotein cholesterol (LDL-C), commonly referred to as “bad” cholesterol, is linked to a reduced risk of cognitive decline. Specifically, LDL-C levels below 1.8 millimoles per litre (mmol/L) were associated with a 26% lower risk of all-cause dementia and a 28% lower risk of Alzheimer’s-related dementia compared to those with LDL-C levels above 3.4 mmol/L.

The large-scale observational study was conducted by researchers from Hallym University College of Medicine in South Korea. It involved data from over half a million individuals, categorizing them into groups based on LDL-C levels and using a matched-pair analysis to compare outcomes. The researchers analysed 192,213 individuals with LDL-C below 1.8 mmol/L and 379,006 with LDL-C above 3.4 mmol/L, creating 108,980 matched pairs for detailed comparison.

An additional protective benefit was observed in individuals with low LDL-C who were also taking statins, medications typically prescribed to lower cholesterol levels. Among these individuals, statin use was associated with a 13% lower risk of all-cause dementia and a 12% lower risk of Alzheimer’s disease-related dementia compared to those who were not on statin therapy.

However, the study also revealed that the cognitive benefits associated with lower LDL-C levels diminished at very low thresholds. When LDL-C levels dropped below 1.4 mmol/L, the risk reduction plateaued at 18% for both dementia and Alzheimer’s. Notably, at levels below 0.8 mmol/L, the protective effects disappeared entirely.

Researchers cautioned that this was an observational study and therefore cannot establish a direct cause-and-effect relationship. They also acknowledged limitations, including the use of baseline LDL-C levels without accounting for changes in cholesterol over time.

Despite these limitations, the findings emphasize the importance of managing LDL-C levels not only for cardiovascular health but also for potentially reducing the risk of neurodegenerative diseases. The study adds to growing evidence supporting the broader systemic benefits of cholesterol management.