Even moderately elevated cholesterol levels in midlife are strongly associated with later risk of Alzheimer’s disease (AD) and vascular dementia (VaD), new research suggests.
Dr. Alina Solomon, lead author (University of Kuopio, Finland), and colleagues used data from the Kaiser Permanente Northern California Medical Group to investigate the relationship between midlife cholesterol and dementia and found that even cholesterol levels of 200 to 239 mg/dL increase risk.
“Both physicians and patients need to know that elevated cholesterol increases the risk not only for heart disease, but also for dementia,” Solomon said. “The most important finding was that even moderately elevated cholesterol at midlife can increase the risk of both AD and VaD later in life.”
The study included 9,844 subjects who had undergone detailed health evaluations from 1964 to1973, when they were ages 40 to 45 years.
Data from 1994 showed that 469 had AD and 127 had VaD. The researchers adjusted for age, education, race/ethnic group, sex, midlife diabetes, hypertension, body-mass index, and late-life stroke. They used cholesterol <200mg/dL as a reference point.
The analysis showed Alzheimer’s disease hazard ratios of 1.23 for midlife borderline cholesterol (200-239 mg/dL) and 1.57 for high cholesterol (>240 mg/dL). Quartile analysis showed that hazard ratios were 1.31 for cholesterol 221-238 mg/dL and 1.58 for 249-500 mg/dL.
VaD hazard ratios were 1.50 for borderline cholesterol and 1.26 for high cholesterol.
Dr. Robert Stewart, King’s College London, UK, said that the Solomon study data are “convincing.”
“In general there is now a large body of evidence that indicates that what is bad for the heart is bad for the brain — that is, that the well-known risk factors for coronary heart disease and stroke are also risk factors for dementia (whether this is classified as Alzheimer’s disease or vascular dementia),” Stewart said.
“So the real message for clinicians is not to do anything differently, but to be aware that what they should be doing already — identifying and treating high cholesterol, high blood pressure, and diabetes and promoting healthy diet and active lifestyles — is likely to have more benefits than originally envisaged and should reduce risk of dementia as well as reducing risk of cardiovascular disease.”
Dementia and Geriatric Cognitive Disorders. August 2009