HDL cholesterol (high-density lipoprotein), popularly known as ‘good cholesterol’, can be harmful to health if its levels are excessively high, since a study led by Monash University has found a relationship between very high levels HDL cholesterol and an increased risk of dementia in older adults.
The researchers also explained that the high levels of HDL associated with the risk of dementia that they detected in their study were rare and were not related to the type of diet, but were more likely to be a sign indicating presence of a metabolic disorder. The results have been published in The Lancet Regional Health-Western Pacific and could help identify people with this symptom and potentially at risk of dementia, especially those aged 75 years or older.
A high level of HDL cholesterol as a predictor of dementia
This research constitutes one of the largest studies on elevated HDL cholesterol levels and dementia in initially healthy older people, most over 70 years of age, enrolled in the ASPREE study. Over an average of 6.3 years, participants with very high HDL cholesterol (>80 mg/dL or >2.07 mmol/L) at baseline were found to have a 27% increased risk of dementia compared to participants with those with optimal levels, while those aged 75 years and older also showed a 42% higher risk compared to those with optimal levels.
Participants with very high HDL cholesterol (>80 mg/dL or >2.07 mmol/L) at baseline had a 27% increased risk of dementia
Very high HDL cholesterol levels were classified as 80 mg/dL (>2.07 mmol/L) or more. The optimal HDL-C level of 40 to 50 mg/dL (1.03 to 1.55 mmol/L) for men and 50 to 60 mg/dL (1.55 to 2.07 mmol/L) for women generally found it beneficial for heart health.
Among the 18,668 participants included in this analysis, 2,709 had very high HDL cholesterol levels when they enrolled in the study, with 38 cases of dementia in people under 75 years of age with very high levels, and 101 in people 75 years of age or older with very high levels.
Dr Monira Hussain, first author and senior researcher at Monash University’s School of Public Health and Preventive Medicine, said further research is needed to find out why very high HDL cholesterol appears to influence the risk of dementia, although he adds that the study’s findings could help improve our understanding of the mechanisms that trigger dementia.
“While we know that HDL cholesterol is important for cardiovascular health, this study suggests that we need more research to understand the role of very high HDL cholesterol in the context of brain health,” he said. “It may be beneficial to consider very high HDL cholesterol levels in dementia risk prediction algorithms,” she concludes.
