Cholesterol Levels Linked to Brain Changes of Alzheimer’s Disease Sept. 12, 2011 -- High cholesterol levels are associated with changes in the brain that are characteristic of Alzheimer’s disease, a new study shows.

For the study, which is published in the journal Neurology, researchers used blood tests to measure cholesterol in 147 Japanese adults 10 to 15 years before their deaths. Fifty of them (or 34%) had been diagnosed with dementia.

Tissue samples from their brains were then examined on autopsy.

Those who had total cholesterol levels over 224 mg/dL in mid- to late life, before they had any symptoms of Alzheimer’s, were at least seven times more likely to have beta-amyloid plaques in their brains by the time they died, compared to people whose cholesterol was under 173 mg/dL. The American Heart Association considers total cholesterol levels below 200 mg/dL to be desirable.

LDL, or “bad,” cholesterol over 155 mg/dL was also strongly associated with the likelihood of developing beta-amyloid plaques, compared to people whose LDL was lower than 106 mg/dL. People with high LDL levels were at least eight times more likely to display pathologic features of Alzheimer’s disease. Ideal LDL levels are felt to fall below 100 mg/dL, according to the AHA.

The relationship to cholesterol values remained after researchers adjusted for other things that are thought to influence the risk of Alzheimer’s disease, like age, sex, body weight, aerobic exercise, blood pressure, a history of stroke, and blood sugar and insulin levels.

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