Changes in blood pressure or blood sugar level can contribute to the development of cardiovascular and metabolic diseases, and a new study reveals that cholesterol could act as a predictor of cognitive problems, as it has found that people older than experience variations in their cholesterol levels, despite not having modified the medication they take to control them, could be at greater risk of developing cognitive impairment and dementia compared to those who maintain stable cholesterol levels.
Research has revealed that the risk is greater among those who have increasingly unstable fluctuations in their cholesterol levels as they increase, compared to those who have steadily decreasing fluctuations. These findings were presented at the American Heart Association (AHA) Scientific Sessions conference in Chicago and are considered preliminary until they are published in a peer-reviewed scientific journal.
The conclusions suggest that “a significant decrease or increase in cholesterol levels in an older adult could be an early sign of possible cognitive problems and the initial stages of dementia,” highlighted Dr. Zhen Zhou, principal investigator of the study and member of the School of Public Health and Preventive Medicine at Monash University in Melbourne, Australia, in an article published by the AHA.
The expert added that “monitoring changes in cholesterol over time in older people could be useful to implement specific preventive strategies at an early stage.” He also cautions that the results should not be interpreted as an indication that those with high cholesterol levels should avoid lowering them, since “reducing cholesterol levels is a well-established practice for reducing the risk of cardiovascular disease.”
A possible blockage of blood flow to the brain
Cholesterol is a substance produced by the liver, which also comes from certain foods, mainly of animal origin such as meat, eggs, cheese and milk. It is measured as total cholesterol, but also by its components: LDL or low-density lipoprotein, known as ‘bad’ cholesterol because it can form plaques in the arteries, and HDL or high-density lipoprotein, considered ‘good’ because it helps reduce cholesterol. risk of heart disease and stroke. Triglycerides are another type of fat that can contribute to unhealthy cholesterol.
Having high cholesterol has also been shown to increase the risk of dementia. The authors of the new study wanted to find out whether unintentional variations in cholesterol levels from year to year were related to cognitive decline or more rapid progression of dementia, compared to those who maintain stable levels.
The analysis included data from 9,846 adults in the United States and Australia who participated in the ASPREE trial, which investigated whether low-dose aspirin could help prevent age-related diseases such as dementia and heart disease. The trial also measured participants’ cholesterol levels and was expanded to an observational study.
Older adults with greater variability in total cholesterol were 60% more likely to develop dementia and 23% more likely to present cognitive impairment than those with less variability
Total cholesterol, LDL, HDL, and triglyceride levels were measured at baseline and at each annual visit for the first three years. Those who started or stopped lipid-lowering medications during the trial were excluded from the analysis. Participants were at least 65 years old and had no history of cardiovascular problems, dementia or cognitive decline. They were divided into four groups based on the magnitude of fluctuations in their total and LDL cholesterol over the three years.
After a follow-up of more than five years, those with greater variability in total cholesterol were 60% more likely to develop dementia and 23% more likely to present cognitive impairment than those with less variability. People with greater variability in LDL were 48% more likely to develop dementia and 27% more at risk of cognitive decline compared to those with less variability. No relationship was found between HDL or triglycerides and the risk of dementia or cognitive decline, nor were there significant differences between those taking or not taking lipid-lowering medications.
Dr. Sudha Seshadri, founding director of the Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases at UT Health San Antonio, who was not involved in this research, clarified that since this is an observational study, it cannot be concluded that fluctuations in cholesterol cause dementia, only the two conditions are related.
In recent years, there has been growing interest among researchers in the role that fluctuations in cardiovascular risk factors could play in heart and brain health. However, most studies have focused on blood pressure, heart rate or blood glucose, according to Zhou, who adds that there is a need to investigate the causes of these fluctuations and whether dementia begins before changes in blood glucose. cholesterol, or if it is a consequence of these. There is also the question of whether other chronic conditions could play a role.
“A possible explanation is that significant fluctuations in cholesterol levels (total and LDL) can destabilize atherosclerotic plaque, which is mainly composed of LDL cholesterol,” Zhou said. This destabilization of arterial plaques can increase the risk of buildup, rupture, and obstruction of blood flow to the brain.
For his part, Seshadri stressed that those who have high cholesterol should continue with medical recommendations to reduce it, not abandon medication and maintain healthy dietary habits. “Consistency is something that doctors recommend anyway, and that could be the message that comes from this,” he concludes.
