High Cholesterol Levels in Elderly Linked to Lower Dementia Risk

[Mikhail]

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

M. M. Mielke PhD*, P. P. Zandi PhD, M. Sjögren MD, PhD, D. Gustafson MS, PhD, S. Östling MD, PhD, B. Steen MD, PhD, and I. Skoog MD, PhD

From the Center on Aging and Health (Dr. Mielke), the Alzheimer Disease Research Center (Dr. Mielke) and the Department of Mental Health (Dr. Zandi), The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD; the Institute of Clinical Neurosciences, Neuropsychiatric Epidemiology Unit (Drs. Sjögren, Gustafson, Östling, and Skoog) and Department of Geriatric Medicine (Dr. Steen), Sahlgrenska Academy at Göteborg University, Göteborg, Sweden; the Department of Family and Community Medicine (Dr. Gustafson), Medical College of Wisconsin, Milwaukee, WI.


* To whom correspondence should be addressed. E-mail: [Ссылки доступны только зарегистрированным пользователям ].



Abstract-- Objective: To examine the longitudinal association between plasma total cholesterol and triglyceride levels and incident dementia. Methods: 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. Results: 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. Conclusions: 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.