Cardiovascular risk factors in midlife strongly linked to risk of dementia

High cholesterol, hypertension, diabetes, and smoking have long been considered and treated as risk factors for cardiovascular disease. A new study has concluded that these same cardiovascular (CV) risk factors in middle age may also increase significantly the risk of dementia in old age. The study of nearly 9,000 northern Californians is published in the January 25 issue of Neurology, the scientific journal of the American Academy of Neurology.

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.