117 Such an association may reflect a long-term direct effect of uncontrolled hyperglycemia on neurodegenerative changes in the brain or an effect of hyperinsulinemia or impaired insulin response, or due to diabetes-related comorbidities such as hypertension and dyslipidemia.118-120 The metabolic syndrome, which is a cluster of multiple vascular risk factors characterized by abnormalities in insulin, blood glucose, lipoprotein metabolism, hypertension,

and obesity, was found to be associated with an increased Inhibitors,research,lifescience,medical prevalence of AD in an elderly Finnish population.121 However, the follow-up study of multiethnic elderly cohort in the US found no association of the metabolic syndrome with either prevalent or incident AD, but two components of the syndrome, diabetes and Inhibitors,research,lifescience,medical hyperinsulinemia, were associated with an increased risk of incident AD122; the authors concluded that examining diabetes and hyperinsulinemia separately might be preferable to using the metabolic syndrome as a single factor to define the risk of AD. Cerebral and cardiovascular disease Stroke, and even clinically silent brain infarcts and white-matter hyperintensities seen on magnetic resonance imaging (MRI) scans, significantly Inhibitors,research,lifescience,medical increased the risk of dementia and AD,123,124 although the observed association with AD has been argued to actually reflect an association with mixed dementia.

The follow-up data of the Cardiovascular Health Study showed that

cardiovascular disease was associated with an increased incidence of dementia and AD, with the highest risk of dementia Inhibitors,research,lifescience,medical being seen in people with peripheral arterial disease, suggesting that extensive peripheral atherosclerosis is a risk factor for AD.125,126 Other cardiovascular disease, (eg, atrial fibrillation and heart failure) and more severe atherosclerosis measured with ankle-to-brachial index have been related Inhibitors,research,lifescience,medical to dementia and to AD as well.127-129 Neuropathological studies suggested that cerebrovascular lesions, atherosclerosis, and neurodegenerative changes in the brain often coexist, and may be coincident processes converging to cause additive damage to the aging brain and to promote clinical expression of the dementia during syndrome.130,131 Psychosocial hypothesis A systematic review found that psychosocial factors and actively integrated lifestyle over the lifespan may reduce the risk of AD and dementia.132 These factors include early-life high educational attainment, adult-life high work complexity, late-life rich social network and high levels of social engagement, and more frequently participating in physically and mentally stimulating activity. High educational attainments and socioeconomic status An association of low Smoothened antagonist education with an increased risk of dementia and AD has been reported in numerous cross-sectional and longitudinal studies.