This Study aimed to investigate the prevalence of various cognitive disorders in the older population (age 55 years and above) of Eskisehir, Turkey, by conducting a cluster sampled door-to-door survey. A total of 3100 inhabitants were screened with the Mini-Mental State Examination (MMSE) and a questionnaire concerning demographic, occupational and social data. Individuals (n = 320) with MMSE scores of <= 25 were assessed according to the 10th Revision of the International Statistical classification of Diseases and Related Health Problems (ICD-10) and were investigated in the more detailed phase 2 study. The overall prevalence of dementia was 8.4%, although it ranged from 2.2% among those aged 55-59 years to 5.3% among those aged 60-64 years, and to 30.4% among those aged 75 or above. vascular dementia was the most common type (51.1%), followed by Alzheimer's dementia (48.8%). In a very small proportion of individuals (0.1%), dementia was due to other causes such as B12 deficiency, a tumour or hydrocephalus. Significant risk factors for dementia were female sex, low education, age, living in a rural area and a family history of dementia. (C) 2009 Elsevier Ltd. All rights reserved.