Heart-Healthy is Brain-Healthy
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EmailMiddle aged people who smoke, have high blood pressure, high cholesterol or diabetes are far more likely to develop dementia in later life.
The research, published in the Journal of Neurology, Neurosurgery and Psychiatry and the Dementia & Geriatric Cognitive Disorders journal, suggests that people should consider modifying their lifestyle in mid-life to avoid developing dementia.
Watch the video above for more on Cholesterol levels and dementia.
Dementia is a growing public health problem affecting older people in developed countries. In the US, where the research took place, estimates show that one in six people older than 70 have dementia. Estimates are that the number of people with dementia will grow threefold by 2050, compared with 2000.
Previous studies have shown that the presence of cardiovascular risk factors including high blood pressure, diabetes, obesity and smoking increase the risk of developing subsequent dementia, but have often failed to show the relationship.
Researchers from the universities of Minnesota, North Carolina and John Hopkins and the University of Mississippi Medical Center studied more than 11,000 people aged 46-70 who were participants in the Atherosclerosis Risk in Communities (ARIC) study in 1990-92.
People underwent a physical examination and cognitive testing at that time and they were followed up until 2004 to see how many were hospitalised with dementia.
After following their progress, the researchers identified 203 cases of hospitalisation with dementia. Smoking, high blood pressure and diabetes were all strongly associated with dementia in white participants and African-Americans.
The results showed that rates of hospitalisation with dementia increased exponentially with age in men and women and in different ethnic backgrounds.
Overall, African-Americans had a two and a half times higher rate of hospitalisation than white people and African-American women in particular had the highest rates of all.
Current smokers were 70% more likely than those who had never smoked to develop dementia, people with high blood pressure were 60% more likely than those without high blood pressure, and people with diabetes were more than twice as likely than those without diabetes to develop it.
No association was found between people who were obese/overweight and dementia in later life. The authors say the results suggest that smoking cessation and prevention or control of high blood pressure and diabetes starting in midlife may have the added benefit of decreasing dementia hospitalisation risk.
They conclude: "Our results emphasise the importance of early lifestyle modification and risk factor treatment to prevent dementia."
In related research, elevated cholesterol levels in midlife - even levels considered only borderline elevated - significantly increase the risk of Alzheimer's disease and vascular dementia later in life. This is the conclusion of a new study by researchers at Kaiser Permanente's Division of Research and the University of Kuopio in Finland. The study appears in the journal Dementia & Geriatric Cognitive Disorders.
The four-decade study of 9,844 men and women found that having high cholesterol in midlife (240 or higher milligrams per deciliter of blood) increases, by 66 percent, the risk for Alzheimer's disease later in life. Even borderline cholesterol levels (200 - 239 mg/dL) in midlife raised risk for late-life vascular dementia by nearly the same amount: 52 percent. Vascular dementia, the second most common form of dementia after Alzheimer's disease, is a group of dementia syndromes caused by conditions affecting the blood supply to the brain. Scientists are still trying to pinpoint the genetic factors and lifestyle causes for Alzheimer's disease.
By measuring cholesterol levels in 1964 to 1973 based on the 2002 Adult Treatment Panel III guidelines (the current practice standard) when the Kaiser Permanente Northern California members were 40 to 45 years old, then following the participants for 40 years, this study is the largest long-term study with the most diverse population to examine the midlife cholesterol levels and late-life dementia. It is also the first study to look at borderline high cholesterol levels and vascular dementia, rather than just Alzheimer's disease.
"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," said the study's senior author. Rachel Whitmer, Ph.D., a research scientist and epidemiologist at the Kaiser Permanente Division of Research in Oakland, Calif. "Considering that nearly 100 million Americans have either high or borderline cholesterol levels, this is a disturbing finding. 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."
"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 the study's lead author, Alina Solomon, MD, a researcher with the Department of Neurology at the University of Kuopio, Finland. "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."
This study, funded by the National Institutes of Health, adds to other research emphasizing the importance of addressing dementia risk factors in midlife, before an underlying disease or symptoms appear, the researchers said.
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The Kaiser Permanente study tracked members of Kaiser Permanente's Northern California Medical Group from 1967 to 2007 by using the multiphasic testing records pioneered by Kaiser Permanente founding physician Morris Collen, MD, who is widely regarded worldwide as a health care informatics pioneer. Of the original 9,844 participants, 598 were diagnosed with Alzheimer's disease or vascular dementia between 1994 and 2007, when the participants were between 61 and 88 years old.
This epidemiological study did not examine the mechanism of the link between cholesterol levels and dementia.
This study is part of an ongoing body of research at Kaiser Permanente to better understand the risk and protective factors for dementia. Dr. Whitmer recently authored two dementia-related studies: one that found a larger abdomen in midlife increases risk of late-life dementia, and one that showed that low blood sugar events in elderly patients with type 2 diabetes increase their risk for dementia. Another Kaiser Permanente study, led by Valerie Crooks of Kaiser Permanente in Southern California, found that having a strong social network of friends and family appears to decrease risk for dementia.
Other authors on this study include: Miia Kivipelto, MD, Ph.D., Department of Neurology, University of Kuopio, Finland, and the Aging Research Center, Karolinska Institutet, Stockholm, Sweden; Benjamin Wolozin, MD, Ph.D., Department of Pharmacology, Boston University School of Medicine; and Jufen Zhou, MS, Kaiser Permanente Division of Research. Additional funding for the study was provided by Kaiser Permanente Community Benefit, the Academy of Finland Marie-Curie EST Program, the Gamla Tjänarinnor Foundation, and Stiftelsen Dementia, Sweden.
Source:
"Risk of dementia hospitalisation associated with cardiovascular risk factors in midlife and older age: the Atherosclerosis Risk in Communities (ARIC) study."
J Neurol Neurosurg Psychiatry2009; doi 10.1136/jnnp.2009.176818
Journal Of Neurology, Neurosurgery & Psychiatry
Emily Schwartz
Golin/Harris International
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