You might want to think twice about that plate of steak and eggs.
A new study that looked at Kaiser Permanente Northern California members over a four-decade period found that even borderline to moderately high cholesterol levels in your 40s can significantly raise the chances of developing dementia later in life.
The study, published Tuesday in the journal Dementia & Geriatrics Cognitive Disorders, found the risk increased by as much as 66 percent among people with high cholesterol in midlife, a level defined as 240 or higher milligrams per deciliter (1.75 pints) of blood.
For those with just moderately high cholesterol -- between 200 and 239 milligrams per deciliter -- the risk of developing vascular dementia, the second-most-common form of dementia after Alzheimer's, increased by 52 percent.
"The thing that struck us as most surprising was that not only was high cholesterol associated with elevated risk of developing dementia later in life, but also borderline levels of cholesterol," said the study's senior author, Rachel Whitmer, a Kaiser research scientist and epidemiologist. "This is a new piece of the puzzle."
The Kaiser research, the largest and most diverse long-term study to examine the link between cholesterol at midlife and the development of dementia later on, adds to a growing body of evidence linking cholesterol and vascular health with the two most common forms of dementia.
Bill Fisher, chief executive of the Alzheimer's Association of Northern California and Northern Nevada, said Kaiser's results were consistent with many studies over the last five or six years that show a correlation between cardiovascular health and dementia.
He added that genetic components to the disease, such as an inherited type of protein, can't be changed with diet and exercise. "But we do say, what's good for the heart is good for your brain. There's a lot of data behind that."
More than 5 million Americans suffer from Alzheimer's disease, an incurable brain disorder and the sixth-leading cause of death. Vascular dementia is linked to strokes, but it lacks the abnormal brain structures known as plaques and tangles associated with an Alzheimer's diagnosis. This form of dementia is caused by blockages to the brain's blood supply.
The Kaiser study looked at 9,844 men and women who were 40 to 45 years old between 1964 and 1973 when their cholesterol levels were first collected. Of the total participants, 469 were diagnosed with Alzheimer's disease between 1994 and 2007 when the members were between 61 and 88 years old; 127 developed vascular dementia.
The tests did not break down cholesterol to examine the impact of the ratio of "good" to "bad" cholesterol on developing dementia.
Whitmer found the overall results encouraging, especially for the estimated 100 million Americans with moderately high cholesterol who may be able to reduce their levels without medications.
"This is a modifiable risk. We do know cholesterol can be lowered with exercise, diet and lifestyle changes," she said.
The study does not explain why people with high cholesterol tend to develop these diseases in greater numbers than those in the normal range.
Dr. Robert Mahley, president of the J. David Gladstone Institutes, praised Kaiser's study and said the research indicates proper cholesterol levels may need to be re-evaluated.
"Certainly, it sends a major red signal that what many people consider to be a normal cholesterol level is not normal cholesterol," he said.
Key risk factors for developing Alzheimer's disease:
Age: Most Alzheimer's patients are over 65, and risk of developing the disease increases with age.
Family history: Those who have a close relative with Alzheimer's are more likely to develop the disease.
Genetics: Scientists have identified an Alzheimer's risk gene, a protein variant.
Vascular health: Good heart health, including lowering cholesterol, is linked to lower disease rates.
Healthy aging: Keeping the brain active, being physically fit and maintaining social connections may offer some protection.
Head injuries: There appears to be a link between serious head injuries and developing Alzheimer's.
Source: Alzheimer's Association.
(E-mail Victoria Colliver at vcolliver(at)sfchronicle.com.)
(Distributed by Scripps Howard News Service, www.scrippsnews.com.)
Must credit the San Francisco Chronicle
Post new comment