Author Affiliations: Clinical Trial Service Unit and Epidemiological Studies Unit, University of Oxford, Oxford, England.
Stroke and dementia are among the most common diseases affecting the brain in older persons and account for most cases of disability requiring nursing care in this age group.1 The incidence of these diseases increases exponentially with age. Consequently, improvements in life expectancy have resulted in a substantial increase in the absolute number of individuals with dementia and cognitive impairment in recent decades. Dementia is characterized by an insidious, slowly progressive memory loss with alteration of higher intellectual function and cognitive abilities. Among the subtypes of dementia, Alzheimer disease and vascular dementia have distinct clinical and pathological features, but these 2 disorders frequently coexist and the combination is associated with a greater severity of cognitive impairment.2
Clarke RJ, Bennett DA. B Vitamins for Prevention of Cognitive DeclineInsufficient Evidence to Justify Treatment. JAMA. 2008;300(15):1819-1821. doi:10.1001/jama.300.15.1819