While high levels of good cholesterol are believed to be better for health, abnormally high levels of it may increase the risk of dementia in older adults, a new study reveals.
The study, led by researchers from Monash University, shows that very high levels of high-density lipoprotein cholesterol (HDL-C), colloquially referred to as ‘good cholesterol’ are associated with an almost 30% increased risk of dementia risk. The findings were particularly pronounced in people aged 75 and older, with a 42% increased risk, the university’s press statement revealed.
Published in the journal The Lancet Regional Health—Western Pacific, the large-scale study, is part of the ASPREE project involving over 18,668 participants. Over an average duration of six years, participants with very high HDL-C (80 mg/dL or above) were found to have a 27% higher risk of dementia compared to those with optimal HDL-C levels, the statement explained.
The optimal level of HDL-C is 40 to 60 mg/dL for men and 50 to 60 mg/dL for women and these are considered to be beneficial for heart health.
The study findings could help improve understanding of the mechanisms behind dementia and how high levels of good cholesterol might play a role in it. “While we know HDL cholesterol is important for cardiovascular health, this study suggests that we need further research to understand the role of very high HDL cholesterol in the context of brain health,” first author Monira Hussain said in the statement.
Considering very high HDL cholesterol levels in prediction algorithms for dementia risk could be beneficial, Hussain adds.
Previous studies have also looked into how high levels of HDL-C might be linked to health risks. For instance, a study presented at the European Society of Cardiology Congress in 2018 showed that very high levels of HDL-C could be associated with an increased risk of heart attack and death. It may be time to change the way we view HDL-C, study author Marc Allard-Ratick said in a press statement.
Traditionally, physicians have told their patients that the higher your 'good' cholesterol, the better. However, research suggests that this may no longer be the case, he added.