High cholesterol levels in late life assotiated with a reduced risk of dementia

Department of Mental Health, Johns Hopkins University, Baltimore, Maryland, United States
Neurology (Impact Factor: 8.29). 06/2005; 64(10):1689-95. DOI: 10.1212/01.WNL.0000161870.78572.A5
Source: PubMed


To examine the longitudinal association between plasma total cholesterol and triglyceride levels and incident dementia.
Neuropsychiatric, anthropometric, laboratory, and other assessments were conducted for 392 participants of a 1901 to 1902 birth cohort first examined at age 70. Follow-up examinations were at ages 75, 79, 81, 83, 85, and 88. Information on those lost to follow-up was collected from case records, hospital linkage system, and death certificates. Cox proportional hazards regression examined lipid levels at ages 70, 75, and 79 and incident dementia between ages 70 and 88.
Increasing cholesterol levels (per mmol/L) at ages 70 (hazard ratio [HR] 0.77, 95% CI: 0.61 to 0.96, p = 0.02), 75 (HR 0.70, CI: 0.52 to 0.93, p = 0.01), and 79 (HR 0.73, CI: 0.55 to 0.98, p = 0.04) were associated with a reduced risk of dementia between ages 79 and 88. Examination of cholesterol levels in quartiles showed that the risk reduction was apparent only among the highest quartile at ages 70 (8.03 to 11.44 mmol/L [311 to 442 mg/dL]; HR 0.31, CI: 0.11 to 0.85, p = 0.03), 75 (7.03 to 9.29 mmol/L [272 to 359 mg/dL]; HR 0.20, CI: 0.05 to 0.75, p = 0.02), and 79 (6.82 to 9.10 mmol/L [264 to 352 mg/dL]; HR 0.45, CI: 0.17 to 1.23, p = 0.12). Triglyceride levels were not associated with dementia.
High cholesterol in late life was associated with decreased dementia risk, which is in contrast to previous studies suggesting high cholesterol in mid-life is a risk factor for later dementia. The conflicting results may be explained by the timing of the cholesterol measurements in relationship to age and the clinical onset of dementia.

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Available from: Bertil Steen, Aug 22, 2015
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    • "Many case -control studies have also confirmed that mild hypercholesterolemia accompanies late-onset AD [49] [62] [63]. However, a 32- year long follow-up study of 1462 women has failed to find an association of mid-life hypercholesterolemia with increasing risk of AD, and even some studies have indicated that a high blood cholesterol especially in latelife is actually protective against AD [64] [65] [66]. The statin group of cholesterol lowering agents has been shown to produce beneficial effects in AD subjects in some studies [67]. "
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    • "Mielke et al. indicated that high total cholesterol level in late life is associated with a reduced risk of dementia. Taken together with our result showing higher cholesterol was associated reduction of WMLs, high cholesterol might be associated with better healthy status in late life (Mielke et al. 2005). Moreover, statin treatment may protect the vessels of the brain and increase chances of survival while also being associated with worsening WMLs (Longstreth et al. 2005). "
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