Perea-Bartolome et al. BMC Public Health 2011, 11:504 http://www.biomedcentral.com/1471-2458/11/504 healthcare costs: drugs, diagnostic studies, medical visits, etc. If the indirect costs associated with the disease are also taken into account, then the figure per patient reaches 19,000 euros per year. During the year 2004, the cost totaled over 8200 million euros in Spain alone [7]. Although cognitive impairment is the most relevant symptom, dementia is usually also associated to different behavioral, psychological and functional manifestations that affect the functional and executive capacities of the individual - interfering with normal family, social and occupational activities, and lessening the quality of life of both the patients and their caregivers. Dementia is one of the main causes of early patient institutionaliza- tion. It has been estimated that behavioral or neuropsy- chiatric symptoms can manifest in 50% of all elderly patients with dementia, and the frequency is moreover higher among institutionalized individuals [4,8]. These symptoms can show diverse presentations, in any evolu- tive stage of the disease, and typically manifest in multi- ple and oscillating forms [4]. At present, the most common cause of dementia is Alzheimer’s disease (AD), of probable multifactorial origin (genetic, environmental, toxic, etc.), followed by vascular dementia (VD). The role of cerebrovascular disease as a cause of dementia has been recognized for over a century. We are now witnessing a redefinition of the different forms of VD, with introduction of the concept of vascular cognitive impairment, designed to identify the early stages of a process hypothetically amenable to preventive intervention and treatment. Together with the classical vascular lesions (arterial and lacunar infarctions), other types of cerebrovascular lesions are becoming known such as leukoaraiosis or incomplete infarctions, which contribute to the devel- opment of intellectual impairment, and increased insight is being gained to the clinical, neuropsychologi- cal and radiological correlations involved. Behavioral and psychological manifestations are increasingly investigated and recognized as symptoms inherent to VD [9,10]. Descriptive, analytical and interventional epidemiological studies have underscored the relevance of vascular factors as causal agents in dementia [11,12]. Another important epidemiological aspect in the field of vascular cognitive impairment refers to cognitive impairment presenting in stroke patients. Up to 30% of all patients with cerebral infarction develop dementia in the three months following stroke - this representing a 9-fold greater risk versus the controls without stroke [12]. The repetition of stroke may trig- ger dementia in some but not in all cases, and many patients develop dementia without any apparent under- lying clinical event. Furthermore, in many cases the observed dementia corresponds to Alzheimer’s disease instead of vascular dementia. This point is important if Page 2 of 8 the vascular component of mixed dementia is amen- able to preventive treatment. Different strategies have been proposed for the pre- vention of dementia, though none have yielded positive results. Given the absence of quality clinical evidence supporting their use, drug treatments (statins, hormone replacement therapy or nonsteroidal antiinflammatory drugs (NSAIDs)) are not advised for the primary prevention of dementia [11]. This discouraging reality is applicable to most dementias, since these are due to Alzheimer’s disease, but it is possible to prevent the sec- ond most common cause of dementia, i.e., vascular dementia [1,3,4], which manifests as a consequence of cerebrovascular disease. Regarding the primary preven- tion of dementia, the PAPPS study [13] recommends remaining socially and mentally active, physical activity, and the observation of healthy living habits, with ade- quate control of cardiovascular risk factors - particularly correct blood pressure control. Cardiovascular diseases are the main cause of death in Spain, and are attributable particularly to cerebrovascu- lar disorders and ischemic heart disease. Arterial hypertension is a systemic condition that pre- ferentially affects three body organs: the heart, kidneys and brain. In contrast to the heart and kidneys, which are systematically evaluated in clinical practice, brain function is often neglected. Hypertension and dementia are common disorders in the population over 65 years of age. It has been estimated that 8% and 65% of these individuals suffer dementia and hypertension, respec- tively [14]. From this age onwards, the prevalence of dementia increases exponentially, doubling every 5 years and reaching 28.5% in people aged 90 years or older (EURODEM study)[15,16]. The results of epidemiological studies in reference to the association between these two disorders vary depending on the methodology employed [17]. Thus, while cross-sectional studies have reported contradictory results [18-21], longitudinal surveys point to a positive relationship between the presence of arterial hyperten- sion in middle age and mild cognitive impairment 15-20 years later [22-24]. No such association has been observed when arterial hypertension develops at an older age [25-27]. Skoog et al. [28] found arterial hyper- tension at 70 years of age to be greater in subjects who developed dementia between 79 and 85 years of age. However, during the years preceding the onset of dementia, blood pressure decreases in comparison with those subjects who do not develop dementia. Similar findings have been published by Hanon [29] and Verghese [30]. The correlation between blood pressure and mild cognitive impairment is more complex than a simple lineal relationship. Chronic hypertension predisposes to mild cognitive impairment and the