Yearly lipid fluctuations linked to dementia, cognitive decline in older adults
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Key takeaways:
- Year-to-year variability in LDL and total cholesterol was tied to risk for dementia and cognitive decline in older adults.
- Variability in triglycerides and HDL was not linked to risk for cognitive decline.
CHICAGO — High year-to-year cholesterol variability was linked to increased risk for cognitive decline and dementia among older adults, a speaker reported.
However, fluctuations in triglycerides and HDL levels were not associated with dementia or cognitive decline in this population, according to data presented at the American Heart Association Scientific Sessions.
“Cholesterol levels tend to fluctuate more in older adults due to changes in metabolism and the effects of aging. As a result, a single measurement in this age group may only capture cholesterol levels during a specific time of period, making it less predictive of long-term cardiovascular risk,” Zhen Zhou, PhD, postdoctoral research fellow in the School of Public Health and Preventive Medicine at Monash University in Melbourne, Australia, told Healio. “Monitoring cholesterol changes over time may provide additional risk information for predicting an older adult’s risk for heart disease, stroke, and conditions like dementia, which are closely linked to vascular health.”
Zhou and colleagues used data from the randomized ASPREE trial and the extended follow-up ASPREE-XT study to evaluate the impact of year-to-year lipid variability on risk for cognitive decline and dementia in older adults.
For the ASPREE trial, researchers enrolled 19,114 patients in the U.S. and Australia aged at least 70 years without CVD, dementia and disability at baseline, who were randomly assigned to either aspirin 100 mg per day or placebo (44% men).
As Healio previously reported, low-dose aspirin did not reduce CVD risk compared with placebo among older adults and was associated with an increased risk for major hemorrhage among ASPREE participants. For ASPREE-XT, the maximum follow-up was 11 years.
For the present study, the researchers included 9,846 ASPREE and ASPREE-XT participants with cholesterol measured at baseline and first 3-year annual visits, and year-to-year variability was based on variability independent of mean measures of total cholesterol, LDL, HDL and triglycerides. Median follow-up was 5.8 years for dementia and 5.4 years for cognitive impairment without dementia.
The mean age was 74 years, more than half were women and nearly 80% had diabetes. One-quarter of participants had a family history of dementia, average systolic BP was 139 mm Hg and nearly three-quarters had overweight or obesity.
Compared with participants with the lowest year-to-year variability, the researchers reported that individuals with the highest total cholesterol variability (HR = 1.6; 95% CI, 1.23-2.08) and LDL variability (HR = 1.48; 95% CI, 1.15-1.91) had higher risk for dementia.
Similarly, they observed that individuals with the highest total cholesterol variability (HR = 1.23; 95% CI, 1.08-1.41) and LDL variability (HR = 1.27; 95% CI, 1.11-1.46) had increased risk for cognitive impairment without dementia compared with those with the lowest variability of either.
“Older individuals with fluctuating cholesterol levels unrelated to use of lipid-lowering medications, particularly those experiencing significant year-to-year variations, may be at a higher risk of dementia and cognitive impairment compared to those with relatively stable cholesterol levels. This group may warrant closer monitoring and proactive preventive interventions,” Zhou told Healio. “It is important to note that we excluded participants who initiated or discontinued lipid-lowering medications during the lipid variability measurement period. This approach was intended to isolate changes in lipid levels that were independent of any alterations in lipid-lowering treatment.”
In other findings, elevated year-to-year total cholesterol and LDL variability were associated faster decline in global cognition, episodic memory, psychomotor speed and the composite score (P for all < .001), but no strong evidence was found between HDL and triglyceride variability and dementia and cognitive decline, according to the study.
Zhou stated the study was limited by its observational design, and therefore prone to residual confounding bias. He also said the design does not allow for a causal relationship between lipid variability and dementia and/or cognitive impairment to be established.
“Before these findings can inform clinical practice, they need validation through additional studies, particularly in older populations with diverse characteristics,” Zhou said. “Future research should also focus on elucidating the mechanisms behind the link between cholesterol variability and dementia risk to determine whether it serves as a genuine risk factor, a precursor, or merely a biomarker of dementia.”
Reference:
- Unexplained changes in cholesterol may help identify older adults at risk for dementia. https://newsroom.heart.org/news/unexplained-changes-in-cholesterol-may-help-identify-older-adults-at-risk-for-dementia. Published Nov. 11, 2024. Accessed Nov. 26, 2024.
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Zhou Z, et al. Abstract 4142561. Presented at: American Heart Association Scientific Sessions; Nov. 16-18, 2024; Chicago.
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