General practitioners, geriatricians, neurologists and health care professionals all over the world will be facing by 2040 the diagnostic, therapeutic and socioeconomic challenges of over 80 million people with dementia, 70% of which will be residing in the least developed world countries. There are currently 18 million people with dementia in Europe, Africa, Asia and Latin America, and nearly 29 million demented subject are predicted by 2020 [1
]. There is, however, a striking possibility of underestimation, not only in developing countries, due to inadequate diagnosis, lack of awareness and low education [4
Dementia is one of the most common diseases in the elderly, with crude prevalence rates between 5.9-9.4% for subjects aged over 65 in the European Union [5
]. The lowest age- and gender-specific prevalence of all-causes dementia reported in the literature is 61.1% among women aged 100 or greater [6
]. Dementia drastically affects daily life and everyday personal activities. It is often associated with behavioural symptoms, personality change and numerous clinical complications, it increases the risk for urinary incontinence, hip fracture, and – most markedly – increases the dependence on nursing care. The costs of care for patients with dementia are therefore immense [9
This review will focus on specific aspects of dementia prevention. Prevention appears to be particularly prominent among anti-dementia strategies because of the lack of cure for dementia [10
] and because it can be carried out within a multidimensional scheme with the highest chances of success if adopted in the early adulthood.
Primary prevention is directed against dementiaprior to its biological onset or against dementia’s risk factors, while secondary prevention refers to the early detection of asymptomatic disease with associated opportunities for intervention before symptoms are evident. However, the US Preventive Services Task Force suggests there is insufficient evidence to support instituting a universal dementia screening programme[11
]. Syndromes of cognitive impairment in non-demented older adults have been the focus of studies aiming to identify subjects at high risk to develop dementia. Mild cognitive impairment (MCI) is characterized by isolated memory deficits in non-demented persons with subjective memory problems, normal general cognitive functioning, and intact activities of daily living [12
]. In the attempt of avoiding dementia development, there are several risk factors to be taken into account, some of which are non-modifiable and include age with age-influencing early-life deleterious conditions [13
], gender, and genetic influence [14
]. In addition, there are several inborn physical attributes, factors such as illiteracy and lack of early education, environmental stress, as well as accidents and traumas that have been associated with increased risk for dementia [13
A great deal of attention is being dedicated to the identification and modulation of those factors which have a large potential to be managed before the onset or during the early asymptomatic course of the disease. These include vascular and lifestyle factors. Among vascular risk factors, considerable evidence from randomized controlled trials and longitudinal cohort studies has established the relationship between hypertension and dementia as well as between hyperlipidemia and dementia. Both systolic hypertension above 160 mmHg and serum cholesterol above 6.5 mmol/L are known to be associated with an increased RR of 1.5 and 2.1 to develop AD [reviewed in 15]. Based on the recommendations of the Third Canadian Consensus Conference on Diagnosis and Treatment of Dementia held in March 2006 [15
], statin therapy, acetylsalicylic acid and carotid artery stenosis reopening on a first level of evidence and control of type 2 diabetes mellitus, hyperlipidemia and hyperhomocysteinemia on a second level of evidence should not be recommended with the single specific purpose of reducing the risk of dementia. Similarly, a recent Cochrane review concluded that there was insufficient evidence to suggest the use of statins for the prevention of AD based on two prospective randomised, placebo-controlled studies (RCTs); the Heart Protection Study and the PROSPER study. Both studies examined the effects of statins in subjects aged over 70 years of age. However, these RCTs do not address the primary epidemiological observations and nested case-control studies, that reduction of serum cholesterol in midlife offers benefit [16
The aim of this work is to critically discuss some of the main results reported recently in the literature in this respect and to provide the patho-physiological rationale for the control of dyslipidemia in the prevention of dementia onset and progression.