Each of these four CV risk factors (diabetes, hypertension, high cholesterol, and smoking) identified at midlife (age 40 to 44) was associated with a 20 to 40 percent increased risk of dementia in later life. Compared to those with no risk factors, those with two of the risk factors were 70 percent (or .7 times) more likely to be diagnosed with dementia; those with three were more than twice as likely; while individuals unfortunate enough to have all four risk factors had a 237 percent (or 2.37 times) greater risk of being diagnosed with dementia.
Correspondingly, treating one's risk factors for heart disease may also reduce the risk for dementia. Earlier treatment may have an even greater benefit by virtue of the cumulative effect of longer exposure to protective therapies.
By risk factor, those with diabetes were 46 percent more likely to develop dementia. Participants with high total cholesterol were 42 percent more likely. Those with hypertension (high blood pressure) were 24 percent more likely. Participants who reported ever smoking at midlife were 26 percent more likely to develop dementia. The effects of CV risk factors on prevalence of dementia were not significantly different among race or gender subgroups.
While previous studies have reported an association between individual CV risk factors and dementia, whether these risk factors in midlife are prospectively associated with risk of dementia in older age had not been thoroughly investigated.
"The real strength of our study is the large, multiethnic cohort of men and women, followed up for 27 years, all with equal access to medical care," said study author Rachel Whitmer, PhD, of Kaiser Permanente Division of Research in Oakland, Calif.
This study was supported by a grant from the National Institutes of Health.
The American Academy of Neurology, an association of more than 18,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Alzheimer's disease, epilepsy, Parkinson's disease, multiple sclerosis, and stroke.
For more information about the American Academy of Neurology, visit its Website at www.aan.com .
Neurology