An Estimate of Attributable Cases of Alzheimer Disease and Vascular Dementia due to Modifiable Risk Factors: The Impact of Primary Prevention in Europe and in Italy

Abstract

Background: Up to 53.7% of all cases of dementia are assumed to be due to Alzheimer disease (AD), while 15.8% are considered to be due to vascular dementia (VaD). In Europe, about 3 million cases of AD could be due to 7 potentially modifiable risk factors: diabetes, midlife hypertension and/or obesity, physical inactivity, depression, smoking, and low educational level. Aims: To estimate the number of VaD cases in Europe and the number of AD and VaD cases in Italy attributable to these 7 potentially modifiable risk factors. Methods: Assuming the nonindependence of the 7 risk factors, the adjusted combined population attributable risk (PAR) was estimated for AD and VaD. Results: In Europe, adjusted combined PAR was 31.4% for AD and 37.8% for VaD. The total number of attributable cases was 3,033,000 for AD and 873,000 for VaD. In Italy, assuming a 20% reduction of the prevalence of each risk factor, adjusted combined PAR decreased from 45.2 to 38.9% for AD and from 53.1 to 46.6% for VaD, implying a 6.4 and 6.5% reduction in the prevalence of AD and VaD, respectively. Conclusion: A relevant reduction of AD and VaD cases in Europe and Italy could be obtained through primary prevention.

A new dawn of preventing dementia by preventing cerebrovascular diseases

“…21 A recent study showed that vascular risk factors (diabetes, midlife hypertension, midlife obesity, physical inactivity, and smoking) accounted for approximately 21% of Alzheimer's disease and 17% of vascular dementia. 22 Assuming a 20% reduction in the prevalence of above vascular risk factors, depression, and low educational level implied a 6.4% and 6.5% reduction in the prevalence of Alzheimer's disease and vascular dementia. 22 Considering that approximately 90% of stroke is attributable to modifiable risk factors, 23 preventing dementia by controlling vascular risk factors and cerebrovascular diseases may be promising.…”

“…22 Assuming a 20% reduction in the prevalence of above vascular risk factors, depression, and low educational level implied a 6.4% and 6.5% reduction in the prevalence of Alzheimer's disease and vascular dementia. 22 Considering that approximately 90% of stroke is attributable to modifiable risk factors, 23 preventing dementia by controlling vascular risk factors and cerebrovascular diseases may be promising. Nevertheless, a systematic review conducted by the Agency for Healthcare Research and Quality concluded that insufficient high strength evidence existed to justify a public health campaign to encourage people to adopt lifestyle interventions to prevent or slow cognitive decline and dementia.…”

Impaired Cerebral Vasomotor Reactivity in Alzheimer’s Disease

“…These changes may appear before the clinical manifestation [ 25 ]; also people with Apolipoprotein E high risk alleles may have an impaired baseline vascular function [ 26 ]. Although the pathophysiological processes of these alterations in CVMR within the context of dementia and AD are not fully understood, it is well known that CVD and traditional vascular risk factors such as age, dyslipidemia, diabetes mellitus, hypertension, smoking, and metabolic syndrome can individually lead to alterations in CVMR, fostering the vascular dysfunction in AD [ 5 ]. A population-based study published by Wolters et al revealed that subjects with higher CVMRs were less likely to develop AD (hazard ratio of 0.84) particularly those carrying APOe4 alleles (hazard ratio of 0.77) at 11.5 years of follow-up; these results give clinical usefulness to the measurement of CVMR in healthy individuals at risk [ 27 ].…”

“…On the other hand, epidemiological studies have demonstrated that cardiovascular disease (CVD) represents a risk factor for AD development and progression. Common CVD risk factors as hypertension, diabetes mellitus, and dyslipidemia are associated with increased AD frequency [ 5 ]. Particularly, participants with peripheral arterial disease (PAD) have a relative risk (RR) of 2.5 to develop AD, relative to those without PAD [ 6 ].…”

Early diagnosis and treatment of Alzheimer’s disease: new definitions and challenges

“…For almost two decades, there has been evidence that a reduction in the prevalence of risk factors has a potential impact on dementia prevalence. 140,141 One-third of cases are probably preventable by addressing nine major modifiable risk factors: midlife hypertension, midlife obesity and diabetes, late-life depression, physical inactivity, smoking, social isolation, and 11 to 12 years of formal education. Peripheral hearing loss was recognize as a significant and modifiable risk factor after the results of a meta-analysis.…”