RESEARCH ARTICLE Epidemiologic studies of m e A Background

Cognitive function refers to those mental processes that impairment is a major health concern affecting loss of independence in daily activities in old age. Thus, special Beydoun et al. BMC Public Health 2014, 14:643 http://www.biomedcentral.com/1471-2458/14/6439.6 % to 32 % for the 85–89 age category and from 41 % toMD 21224, USA Full list of author information is available at the end of the articleare crucial for the conduct of the activities of daily living. Such mental processes include attention, short-term and long-term memory, reasoning, coordination of movement and planning of tasks [1]. The prevalence of brain dis-orders affecting cognition (such as stroke and dementia) increases steadily in a linear fashion with age [2]. Cognitive attention should be devoted to its prevention [3]. Dementia is relatively frequent in the elderly population and was shown to affect about 6.4 % of European subjects over the age of 65 years [4]. A review of 50 original articles published between 1989 and 2002 using international data showed that prevalence of dementia for the very old group (85 years and over) varied from 16.7 % in China [5] to 43% in Germany [6]. This variability was also reflected within separate age groups among the very old, ranging fro