“Good” cholesterol may not be so good after all.
Having either high or low levels of high-density lipoprotein, or HDL, cholesterol may raise the risk of dementia in older persons, according to a recent study published on Wednesday in Neurology. The research is additional proof that maintaining HDL cholesterol within a particular range is crucial for the health of the heart and the brain.
More than 184,000 individuals, with an average age of 70, participated in the study, which was funded by the National Institute on Aging and the National Institutes of Health. Researchers monitored cholesterol levels, health habits, and the occurrence of dementia during a period of nearly 13 years using a mix of questionnaires and computerized information from the Kaiser Permanente Northern California health plan.
In the research, the average HDL cholesterol level was 53.7 mg/dL, which is within the acceptable limit of 40 mg/dL for males and 50 mg/dL for women. Over the course of the trial, dementia was more likely to develop in people whose cholesterol levels deviated too far from these targets. The highest of the three groups, those with levels at least 65 mg/dL, had a 15% higher risk of dementia. The risk was 7% higher for those with the lowest levels—11 to 41 mg/dL—than for the intermediate group.
The findings suggest a link between low or high levels of HDL cholesterol and dementia, but they do not conclusively demonstrate that either level caused the disease.
Exercise and healthy lifestyle choices enable HDL cholesterol to transform into HDL particles. According to Dr. Hussein Yassine, an endocrinologist at the Keck Medicine of USC who specializes in how changes in lipid metabolism impact a person’s risk of developing Alzheimer’s disease, this enables HDL to carry out some of the crucial tasks for which it is lauded, including removing LDL cholesterol from the arteries and transporting it to the liver, where the body gets rid of it.