EU-funded study: elevated cholesterol in 40s raises late-life dementia risk
The risk of developing Alzheimer's disease and vascular dementia is greater for people who had elevated blood cholesterol when they were in their 40s compared with those whose cholesterol levels were at optimal levels, an EU-funded study has found. The research results, funded in part by the EU's Marie Curie Early Stage Training (EST) Programme, are published in the journal Dementia & Geriatric Cognitive Disorders.
Researchers at the Kaiser Permanente Division of Research in the US and the University of Kuopio in Finland assessed data taken from 9,844 men and women over a 40-year period. According to their calculations, the risk for developing Alzheimer's disease later in life increased by 66% when people had cholesterol of at least 240 milligrams per decilitre (mg/dL) of blood in mid-life.
But the researchers also found that even levels that were between 200 to 239 mg/dL in mid-life raised late-life vascular dementia risk by 52%. Vascular dementia is the second leading form of dementia after Alzheimer's disease and is associated with problems affecting the circulation of blood to the brain.
Cholesterol levels were grouped into 3 categories based on the 2002 Adult Treatment Panel (ATP) III guidelines: 200 mg/dL (desirable); 200-239 mg/dL and (borderline), and 240 mg/dL (high).
"Our study shows that even moderately high cholesterol levels in your 40s puts people at greater risk for Alzheimer's disease and vascular dementia decades later," explained Dr Rachel Whitmer of the Kaiser Permanente Division of Research. "Considering that nearly 100 million Americans have either high or borderline cholesterol levels, this is a disturbing finding," explained the researcher, who was senior author of the study.
"The good news here is that what is good for the heart is also good for the mind, and this is an early risk factor for dementia that can be modified and managed by lowering cholesterol through healthy lifestyle changes," she added.
The study's subjects, all members of the Kaiser Permanente Northern California Medical Group, had had their blood tested between 1964 and 1973, when they were 40 to 45 years old; they were also members of the group's health plan in 1994. Alzheimer's disease and vascular dementia were determined by medical records between 1994 and 2007.
The results showed that of the 9,844-strong sample, 598 were diagnosed with Alzheimer's disease or vascular disease when they were between 61 and 88 years old.
"Our findings add to the existing body of evidence on a degree of overlap between two dementia types in terms of risk factors, symptoms and neuropathology," said lead author Dr Alina Solomon of the Department of Neurology at the University of Kuopio.
"Dementia and cardiovascular disease are common major health problems, share several risk factors and often occur simultaneously, interacting with one another. A holistic approach that addresses multiple major health problems simultaneously is needed to effectively manage these disorders."
While this was the first study to assess borderline high cholesterol levels and vascular dementia, it did not investigate the mechanisms of the link between cholesterol levels and dementia.
Other researchers participating in the study were from Karolinska Institutet in Sweden and the Boston University School of Medicine in the US.
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