Vascular factors and conditions that may be associated with cognitive decline and dementia include stroke, diabetes, hypertension, congestive heart failure, high fat intake, high cholesterol, smoking, alcohol misuse, atrial fibrillation, low folate, and obesity (Glymour & Manley, 2008). Although there is no definitive evidence linking cardiovascular disease and Alzheimer's disease, studies have found associations between cognitive impairment and cardiovascular disease (Purnell et al., 2009).
Most of the cardiovascular disease risk factors are more common in African Americans and Hispanics (Glymour & Manley, 2008). Geographic variation in the prevalence of cardiovascular disease risk factors may be related to differences in regional dietary patterns. More than 80% of Blacks aged 65+ in 2000 were born in the South, and Southern-born individuals have significantly higher rates of circulatory disease mortality (Glymour & Manley, 2008).
Vascular dementia accounts for a larger proportion of cases of related dementias in African Americans than in Whites (Froehlich et al., 2001). However, as with other dementia disorders, it is unclear whether differences in the prevalence of vascular dementia reflect true differences or are a result of measurement bias because of differences in education, socioeconomic status, or other cultural factors. One recent study found that reducing ethnic and racial disparities in the incidence of Type 2 diabetes could reduce the incidence of cognitive impairment and dementia by 17% (Noble et al., 2012).
A few studies suggest that differences in Alzheimer's disease prevalence cannot be attributed to differences in underlying cardiovascular disease rates. In one study, Black Alzheimer's disease patients had higher crude rates of hypertension than did Whites, but differences in other rates of cardiovascular disease (heart disease, stroke, diabetes) were not significantly different between the groups (Hargrave et al., 1998). In another study, although the cumulative incidence rate of Alzheimer's disease was twice as high among African Americans and Caribbean Hispanics, the presence of cardiovascular or cerebrovascular disease did not contribute to increased risk (Tang et al., 2001).